Hi all,

I'm looking for a 'tank' to test the performance of a small electric
outboard, (PWM speed controllers, batteries, hydrodynamic
slipstreaming mods etc) so am thinking of a circular tank, possibly
about 3' / 90cm in diameter so that I can set the outboard off to one
side and get the water circulating around the tank, rather than just
turbulating in it (as when in a dustbin etc). It would also need at
least around 18" deep sides to stop the water climbing / splashing
out.

So, after a bit of Googling I came across the IBC water containers and
1) wondered if anyone knows where there might be one that still holds
water (at least over the lower half) near Nth London that someone
might like to see the back of and 2) if you think it might be suitable
for my needs please (or if not, why not etc). If not there seem to be
plenty on eBay cheap enough.

Would it being nearly square (all be it with round corners) with maybe
something in the middle to ensure water actually flows 'round' the
container be free moving enough or do you think I'd need to fit a
round liner inside it?

If the bottom (inside) isn't flat or couldn't easily be made flattish
(from a water flow POV) could I use the top half upturned instead (I
could fit my own drain cock etc).

Any other ideas around the above welcome of course. ;-)

Cheers, T i m

T i m wrote:
Hi all,

I'm looking for a 'tank' to test the performance of a small electric
outboard, (PWM speed controllers, batteries, hydrodynamic
slipstreaming mods etc) so am thinking of a circular tank, possibly
about 3' / 90cm in diameter so that I can set the outboard off to one
side and get the water circulating around the tank, rather than just
turbulating in it (as when in a dustbin etc). It would also need at
least around 18" deep sides to stop the water climbing / splashing
out.

So, after a bit of Googling I came across the IBC water containers and
1) wondered if anyone knows where there might be one that still holds
water (at least over the lower half) near Nth London that someone
might like to see the back of and 2) if you think it might be suitable
for my needs please (or if not, why not etc). If not there seem to be
plenty on eBay cheap enough.

Would it being nearly square (all be it with round corners) with maybe
something in the middle to ensure water actually flows 'round' the
container be free moving enough or do you think I'd need to fit a
round liner inside it?

If the bottom (inside) isn't flat or couldn't easily be made flattish
(from a water flow POV) could I use the top half upturned instead (I
could fit my own drain cock etc).

Any other ideas around the above welcome of course. ;-)

Not sure about a round tank, but it would be fairly straightforward to form
a rectangular trough from sheet material (OSB?), drape a thickish sheet of
polythene inside and fill with water?

--
Nige Danton - Replace the obvious with g.m.a.i.l

On Wed, 23 Aug 2017 17:19:05 -0000 (UTC), Nige Danton
wrote:

snip

Any other ideas around the above welcome of course. ;-)

Not sure about a round tank, but it would be fairly straightforward to form
a rectangular trough from sheet material (OSB?), drape a thickish sheet of
polythene inside and fill with water?

Nice 'outside of the box' thinking Nige, thanks. ;-)

An octagonal or even hexagonal box would probably be close enough for
my water-flow needs and could be screwed or (cable-tie?) hinged
together if it had a waterproof lining (I don't think there would be
that much pressure at 18" deep and if there were, nothing a couple of
ratchet straps wouldn't hold)?

It might be easier to make something rectangular (and if I was making
it myself I could of course) with angled inner corners and a central
baffle to create a 'circular' water path?

Cheers, T i m

"T i m" wrote in message
...
Hi all,

I'm looking for a 'tank' to test the performance of a small electric
outboard, (PWM speed controllers, batteries, hydrodynamic
slipstreaming mods etc) so am thinking of a circular tank, possibly
about 3' / 90cm in diameter so that I can set the outboard off to one
side and get the water circulating around the tank, rather than just
turbulating in it (as when in a dustbin etc). It would also need at
least around 18" deep sides to stop the water climbing / splashing
out.

So, after a bit of Googling I came across the IBC water containers and
1) wondered if anyone knows where there might be one that still holds
water (at least over the lower half) near Nth London that someone
might like to see the back of and 2) if you think it might be suitable
for my needs please (or if not, why not etc). If not there seem to be
plenty on eBay cheap enough.

Would it being nearly square (all be it with round corners) with maybe
something in the middle to ensure water actually flows 'round' the
container be free moving enough

Yep.

or do you think I'd need to fit a round liner inside it?

Nope.

If the bottom (inside) isn't flat

It is.

or couldn't easily be made flattish (from a water
flow POV) could I use the top half upturned
instead (I could fit my own drain cock etc).

No need.

Any other ideas around the above welcome of course. ;-)

We use a 44 gal drum with the top cut off

On Wed, 23 Aug 2017 18:11:21 +0100, T i m wrote:

Hi all,

I'm looking for a 'tank' to test the performance of a small electric
outboard, (PWM speed controllers, batteries, hydrodynamic
slipstreaming mods etc) so am thinking of a circular tank,

So, after a bit of Googling I came across the IBC water containers and
1) wondered if anyone knows where there might be one that still holds
water (at least over the lower half) near Nth London that someone
might like to see the back of and 2) if you think it might be suitable
for my needs please (or if not, why not etc). If not there seem to be
plenty on eBay cheap enough.

A concern may how much strength there will be left once to top is cut
off though the one I have seems fairly heavy gauge material and you
still have the reinforcing cage to help with that, but you may have to
cut that down as well.


Would it being nearly square (all be it with round corners) with maybe
something in the middle to ensure water actually flows 'round' the
container be free moving enough or do you think I'd need to fit a
round liner inside it?

If the bottom (inside) isn't flat or couldn't easily be made flattish
(from a water flow POV) could I use the top half upturned instead (I
could fit my own drain cock etc).

The bottom is fairly flat apart from a section a bit lower for the
tap.

To satisfy the above concerns it would seem like a lot of kerfuffle to
do rather than but a round tank in the first place from a suppler like
an agricultural merchant.


How much depth do you need? I've seen an instant garden water feature
made by using a section of concrete pipe lined with an off cut of pond
liner , the latter can often be found as remnants at water garden
supplies but for intermittent use a bit of DPC membrane should
suffice. As would doing the same with a large truck or tractor tyre
but that could lead to disposal problems later.


Any other ideas around the above welcome of course. ;-)


If you go down the IBC route what it originally had in it may have a
bearing, mine had contained a detergent that was for washing
supermarket food crates so rinsed clean easily, some that tend be at
the cheaper end of prices asked have had things like fibre glass resin
in which is harder to deal with for some applications.

You can also get half size 500l ones but being rarer and sough after
tend to actually cost more.


G.Harman

"Rod Speed" wrote in message
...


"T i m" wrote in message
...
Hi all,

I'm looking for a 'tank' to test the performance of a small electric
outboard, (PWM speed controllers, batteries, hydrodynamic
slipstreaming mods etc) so am thinking of a circular tank, possibly
about 3' / 90cm in diameter so that I can set the outboard off to one
side and get the water circulating around the tank, rather than just
turbulating in it (as when in a dustbin etc). It would also need at
least around 18" deep sides to stop the water climbing / splashing
out.

So, after a bit of Googling I came across the IBC water containers and
1) wondered if anyone knows where there might be one that still holds
water (at least over the lower half) near Nth London that someone
might like to see the back of and 2) if you think it might be suitable
for my needs please (or if not, why not etc). If not there seem to be
plenty on eBay cheap enough.

Would it being nearly square (all be it with round corners) with maybe
something in the middle to ensure water actually flows 'round' the
container be free moving enough

Yep.

or do you think I'd need to fit a round liner inside it?

Nope.

If the bottom (inside) isn't flat

It is.

or couldn't easily be made flattish (from a water
flow POV) could I use the top half upturned
instead (I could fit my own drain cock etc).

No need.

Any other ideas around the above welcome of course. ;-)

We use a 44 gal drum with the top cut off

Much simpler for attaching the outboard too, just
clamp it on the same way you do with the boat.

On 8/23/2017 9:22 PM, wrote:
On Wed, 23 Aug 2017 18:11:21 +0100, T i m wrote:

Hi all,

I'm looking for a 'tank' to test the performance of a small electric
outboard, (PWM speed controllers, batteries, hydrodynamic
slipstreaming mods etc) so am thinking of a circular tank,

So, after a bit of Googling I came across the IBC water containers and
1) wondered if anyone knows where there might be one that still holds
water (at least over the lower half) near Nth London that someone
might like to see the back of and 2) if you think it might be suitable
for my needs please (or if not, why not etc). If not there seem to be
plenty on eBay cheap enough.

A concern may how much strength there will be left once to top is cut
off though the one I have seems fairly heavy gauge material and you
still have the reinforcing cage to help with that, but you may have to
cut that down as well.


If you leave it in the metal frame, that will still support the
container adequately. I have a couple which I use to store spring water
and/or harvest rainwater at a stables and these have large (600 mm
square) holes in the top to allow for periodic cleaning with a pressure
washer. (As an aside, standard paddling pool / swimming pool floats
containing a chlorine tablet more or less eliminate algae).

My question is what sort of power are you talking about here? Unless it
is pretty small, it could get exciting. Even a small one will need a
pretty strong and secure support.

On Wed, 23 Aug 2017 21:22:17 +0100, wrote:

snip

A concern may how much strength there will be left once to top is cut
off though the one I have seems fairly heavy gauge material and you
still have the reinforcing cage to help with that, but you may have to
cut that down as well.

Understood.

snip

The bottom is fairly flat apart from a section a bit lower for the
tap.

Ok, thanks. Do you think it would impact the flow of water round the
tank, assuming it's going at about 5mph and I'm not looking for lab
standard of water flow? ;-)

To satisfy the above concerns it would seem like a lot of kerfuffle to
do rather than but a round tank in the first place from a suppler like
an agricultural merchant.

From what I have found so far, such sized tanks are about 250 quid?
;-(

You can get a loft tank for ~£150:

https://www.tanks-direct.co.uk/water-tanks/cold-water-loft-tanks/round-loft-tanks/100-gallon-455-litre-cold-water-loft-tank-b100c.html

Underground tanks are even mo

https://www.tanks-direct.co.uk/water-tanks/water-storage-tanks/1000-litre-water-tanks/1000-litre-underground-water-tank.html

How much depth do you need?

I've not measured accurately yet but something like 18 inches (of
water) should cover it easily. Basically my best hope would be the
space either side of the prop (between the outside of the tank and the
inside barrier (imagine a doughnut)) is about the same as the depth of
water. Eg, if the tank is 4' diameter with a 2' diameter 'centre that
only leaves a 12" width 'channel' for the water (the prop is only
about 9" diameter). So, the centre of the prop could be 6" off the
bottom of the tank and as long as the top of the prop is sufficiently
covered to prevent cavitation, that should work.

http://moto-nautika.com/wp-content/uploads/2015/12/2015-Yamaha-M12-M18-M20-M26-EU-NA-Studio-001.jpg

I've seen an instant garden water feature
made by using a section of concrete pipe lined with an off cut of pond
liner , the latter can often be found as remnants at water garden
supplies but for intermittent use a bit of DPC membrane should
suffice. As would doing the same with a large truck or tractor tyre
but that could lead to disposal problems later.

That's a good idea (half a truck tyre, cut like you would a bagel) but
I don't think it would be deep enough without some additional material
(nice one though).


Any other ideas around the above welcome of course. ;-)


If you go down the IBC route what it originally had in it may have a
bearing, mine had contained a detergent that was for washing
supermarket food crates so rinsed clean easily, some that tend be at
the cheaper end of prices asked have had things like fibre glass resin
in which is harder to deal with for some applications.

Understood. I'll try to get one that has previously contained
something pretty innocuous or has been fully cleaned out.

You can also get half size 500l ones but being rarer and sough after
tend to actually cost more.

I'd need the size the 1000l tanks give I think.

If I go that way I then just need to find something suitable as a
centre (a length of reasonable diameter plastic pie or water container
etc that can have hole in (to stop it trying to float) and some gravel
or summat to hold it in place. Or, if it was an upside-down bucket
shape I could joint it to (underneath) the cross member (4 x 2) that
will also act as the outboard mount.

If I want to make the inside wall of an IBC tank 'rounder' I might be
able to find an 8x4' sheet of some of that thin foam filled plastic,
cut in half down it's length, joined lengthwise (overlap) formed into
a circle and just dropped inside should be sufficient. I might have to
trim it to fit round the tap mount etc? I'll try it without first of
course. ;-)

The idea is to get as clean a flow of water around the circuit as
reasonable so that I can get some reasonable linear flow related
measurements (simulating being on a small dinghy).

I might even try to measure the water speed (Arduino project) as that
and the current drawn are the two main criteria.

Cheers, T i m

On Wed, 23 Aug 2017 21:53:15 +0100, newshound
wrote:

snip

If you leave it in the metal frame, that will still support the
container adequately. I have a couple which I use to store spring water
and/or harvest rainwater at a stables and these have large (600 mm
square) holes in the top to allow for periodic cleaning with a pressure
washer. (As an aside, standard paddling pool / swimming pool floats
containing a chlorine tablet more or less eliminate algae).

Good tip, thanks.

My question is what sort of power are you talking about here? Unless it
is pretty small, it could get exciting. Even a small one will need a
pretty strong and secure support.

It is very small. ;-)

It is a Yamaha M12 (re badged Minn Kota) electric outboard or
'trolling motor' as they call them in The States and gives about 30lb
thrust on full.

'Full' is about 30A and at 12V that would make 360 watts (~0.5 hp).

However, on speed 3 (of 5) pushes our 3m folding dinghy along (3 +
dog) at the rivers speed limit of around 5 mph but silently. ;-)

However, these smaller outboards often use what they call 'speed
coils' (load resistors) to lower the current for the speeds 1-4 and so
I've got a PWM speed controller from China that I can plug in series
and see what speed increases (hopefully) I get for the speeds 1-4. It
may be slightly less efficient on speed 5 as that would normally be
the battery connected directly to the motor. However, whilst it's nice
to have that extra 'oomph (relatively speaking etc), the current draw
is disproportionately high for the increase in hull speed so we
generally don't both and just enjoy the range instead. ;-)

I also recently picked up 6 x 16000 mAh LiPo packs with the though of
making a lighter and higher power replacement for the 60Ah traction
lead acid battery we currently use but the complexity (charging,
storage charging and transporting), cost and risks outweighed the
short term (it's only an issue when carrying the batteries from the
car to the boat) advantages. So I'm probably going to get two (or more
[1]) new lighter traction batteries, mainly to make it easier for the
Mrs to handle.

So the goal is to try to get a days cruising with a combination of
individually weight manageable LA batteries and efficiency
improvements on the outboard (PWM power control, hydrodynamic fairing
on the tubular shaft and a spinner on the prop).

That's why I need a suitable test tank to be able to reasonably
accurately measure or at least compare pre / post 'improvement'
values. ;-) [2]

Cheers, T i m

[1] Basically we are only limited to the weight of battery we would
want to carry in the car as the boat is rated for '4 Persons' and
there would typically be only 2 of us. ;-)

[2] Whilst some of it is academic on the folding boat(s) we intend to
mainly use, I also have a 16' Canadian canoe that would probably give
a higher speed through the water for a given battery load, plus I like
the saying, 'You can manage what you can measure'. ;-)

On Wed, 23 Aug 2017 23:24:54 +0100, T i m wrote:

It is a Yamaha M12 (re badged Minn Kota) electric outboard or
'trolling motor' as they call them in The States and gives about 30lb
thrust on full.

Please let me know how you get on.

I have an electric outboard ("John Azur"), and a PWM controller from China,
presently awaiting tuits...

I've also looked at this and its brothers:
"Digital LCD DC combo Meter Watt Power Volt Amp RC Battery dis charging
Analyzer" http://r.ebay.com/RQX0Go

which does current times voltage over time, and could work as a "fuel gauge"...

If you want to see what's possible -- look for "Torqueedo" outboards. They have
an accurate range estimate in miles in their system, using a GPS. (Note: for the
price, you will be ble to hire someone to paddle you upstream for a week).

As to the tank -- Dunno about round, and the water moving in a circle: the
watter current would speed up, dropping the electric current, and the water
would start to climb up the sides of a circular container, and the outboard
might start to move to the side and the propeller hit the container wall.
Turbulent flow would provide a more constant load.

Other than that: rainwater butt? Inflatable pool? a "Fast set pool", 8 ft diam
for 30 quid (which would required external support for the motor)?

Or, here, I'd be looking at mortar pans, like he bit small, but very cheap
http://www.hornbach.de/shop/Moertelkuebel-PE-rund-90-Liter/274271/artikel.html


Thomas Prufer

On Thu, 24 Aug 2017 08:37:54 +0200, Thomas Prufer
wrote:

On Wed, 23 Aug 2017 23:24:54 +0100, T i m wrote:

It is a Yamaha M12 (re badged Minn Kota) electric outboard or
'trolling motor' as they call them in The States and gives about 30lb
thrust on full.

Please let me know how you get on.

Will do.

I have an electric outboard ("John Azur"), and a PWM controller from China,
presently awaiting tuits...

;-)

I've also looked at this and its brothers:
"Digital LCD DC combo Meter Watt Power Volt Amp RC Battery dis charging
Analyzer" http://r.ebay.com/RQX0Go

I bought something similar recently (supposedly 130A rated) and as it
was from China, probably the same inside. ;-)

which does current times voltage over time, and could work as a "fuel gauge"...

Yup. I was going to use mine for both the testing / modification and
general running stage, at least to start with.

If you want to see what's possible -- look for "Torqueedo" outboards. They have
an accurate range estimate in miles in their system, using a GPS. (Note: for the
price, you will be ble to hire someone to paddle you upstream for a week).

Yup, already looked at those but are way outside my price range and
comfort zone (if something goes wrong outside warranty etc). They also
seem to be a bit noisier than the typical trolling motors?

As to the tank -- Dunno about round, and the water moving in a circle: the
watter current would speed up, dropping the electric current, and the water
would start to climb up the sides of a circular container,

Whilst I'm sure you are right to a degree, this is why the container
needed to be reasonably big to increase the water volume and reduce
the speed. That plus I'm only talking about ~5mph so that shouldn't
become an issue (but I'll keep the thought in my mind of course).

and the outboard
might start to move to the side and the propeller hit the container wall.

Not if I've fitted it it won't weg, plus if the container is
plastic, that won't be as bad as the prop hitting some rocks on the
bottom of the river. ;-(

Turbulent flow would provide a more constant load.

But wouldn't help with my hydrodynamic fairing and prop spinner tests?

Other than that: rainwater butt? Inflatable pool? a "Fast set pool", 8 ft diam
for 30 quid (which would required external support for the motor)?

Yes, I've considered all those as well but don't feel they would be
robust enough to last if left out etc. That said, it's possible that
once I have done my initial tests I won't need it so something I can
fold away might be a good idea. The '4 ring' inflatable paddling pools
look cheap / deep / large enough. I already had a 3 legged design for
a frame that would stand over the pool, support the outboard and any
cylinder that was going to create the 'core' in the middle (an
upturned cylindrical water container or large diameter drain pipe
etc). It would have to be suspended from such a frame if used on an
inflatable pool as it won't be so easy to hold such in place on the
bottom without risk of damaging it etc (but not impossible with care
etc).

Or, here, I'd be looking at mortar pans, like he bit small, but very cheap
http://www.hornbach.de/shop/Moertelkuebel-PE-rund-90-Liter/274271/artikel.html

Yeah, that was the sort of style but as you say, probably a bit small.

Nige's idea about making something from say OSB and lining it with
some DPM or pond liner could be a good compromise as it could be made
fairly cheaply and fairly easily (it could be stitched together using
cable ties) and then flat-packed or reused for other roles if / when
the project was over.

Square (or rectangular) would be the easiest and possibly the most
self supporting (square corners), the top edges could be stiffened
with a bit of batten (and / or the outboard supporting frame) and a
circular inner wall could be formed inside the liner, to manage the
water flow if required.

1 x 11 x 1220 x 2440mm (£15) for the base and two sides and another
for the remaining two sides and maybe some inner corners to make an
octagon plus 20 quid for 3 x m of DPM? A bag of cable ties to stitch
it all together or some lightish line?

I was thinking on that if I wanted to slow the water circulation speed
/ apply some (more) load to the motor I could just build a weir under
the water (engineering bricks?) maybe 90 degrees behind the position
of the outboard around the tank?

Cheers, T i m

In message , T i m
writes

The idea is to get as clean a flow of water around the circuit as
reasonable so that I can get some reasonable linear flow related
measurements (simulating being on a small dinghy).

I might even try to measure the water speed (Arduino project) as that
and the current drawn are the two main criteria.

I have an acrylic bath and a large domestic header tank going in the
next scrap skip. Alternatively, I can lend you a stretch of the river
Lea:-)

--
Tim Lamb

On Thu, 24 Aug 2017 09:19:33 +0100, T i m wrote:

Yup, already looked at those but are way outside my price range and
comfort zone (if something goes wrong outside warranty etc). They also
seem to be a bit noisier than the typical trolling motors?

They have a system I'd love to have: flexible roughly folding-boat-shaped solar
panels, Li-ion batteries and a small motor. If going slowly enough in enough
sun, the panels give enough power to keep on going all day, and end up with full
batteries...

Several (many) thousands, though.

Turbulent flow would provide a more constant load.

But wouldn't help with my hydrodynamic fairing and prop spinner tests?

not at all...

Nige's idea about making something from say OSB and lining it with
some DPM or pond liner could be a good compromise as it could be made
fairly cheaply and fairly easily (it could be stitched together using
cable ties) and then flat-packed or reused for other roles if / when
the project was over.

Square (or rectangular) would be the easiest and possibly the most
self supporting (square corners), the top edges could be stiffened
with a bit of batten (and / or the outboard supporting frame) and a
circular inner wall could be formed inside the liner, to manage the
water flow if required.

Or truly round, using cooper techniques: tongue-and-groove boards, i.e. decking,
cheap paneling? Plain boards, and ratchet straps around the outside?


1 x 11 x 1220 x 2440mm (£15) for the base and two sides and another
for the remaining two sides and maybe some inner corners to make an
octagon plus 20 quid for 3 x m of DPM? A bag of cable ties to stitch
it all together or some lightish line?

Ratchet straps, which are also useful in other ways, afterwards.

I was thinking on that if I wanted to slow the water circulation speed
/ apply some (more) load to the motor I could just build a weir under
the water (engineering bricks?) maybe 90 degrees behind the position
of the outboard around the tank?

Or just stand in the tank!


Thomas Prufer

On Thu, 24 Aug 2017 09:28:49 +0100, Tim Lamb
wrote:

In message , T i m
writes

The idea is to get as clean a flow of water around the circuit as
reasonable so that I can get some reasonable linear flow related
measurements (simulating being on a small dinghy).

I might even try to measure the water speed (Arduino project) as that
and the current drawn are the two main criteria.

I have an acrylic bath

Hmmm, I just read that out to our daughter (she sends her regards btw)
and she asked why I couldn't use our existing corner bath g. Easy to
fill and empty and I can still do my experiments when it's raining.
;-) I just need a lift out frame to mount the outboard on ... ;-)

and a large domestic header tank going in the
next scrap skip.

Thanks for the thoughts and offer Tim. Are we talking a traditional
rectangular water (rather than CH header) galv tank here ... (as you
mentioned the scrap skip) or plastic? If it's plastic and one of the
larger sizes I'd like to consider the dimensions and see if I can do
something with it please?

Alternatively, I can lend you a stretch of the river
Lea:-)

Hehe ... luckily I can get to our bit of the Lea easier than getting
to yours and whilst some of these tests can be conducted 'live', I'd
prefer to do them on the bench (so to speak) and leave the real
boating to being just 'fun'. ;-)

Cheers, T i m

On Thu, 24 Aug 2017 10:45:46 +0200, Thomas Prufer
wrote:

On Thu, 24 Aug 2017 09:19:33 +0100, T i m wrote:

Yup, already looked at those but are way outside my price range and
comfort zone (if something goes wrong outside warranty etc). They also
seem to be a bit noisier than the typical trolling motors?

They have a system I'd love to have: flexible roughly folding-boat-shaped solar
panels, Li-ion batteries and a small motor. If going slowly enough in enough
sun, the panels give enough power to keep on going all day, and end up with full
batteries...

Maybe in California Thomas g, but I agree, they seem to be a very
clever and well thought out package.

Several (many) thousands, though.

Quite. My point was I can buy several Minn Kota outboards and traction
batteries for the same money *and* could use easily use a car battery
if I had to or try LiPo or LiIon if I wanted to. The Torquedo is a bit
too propitiatory for my wallet and needs.

Turbulent flow would provide a more constant load.

But wouldn't help with my hydrodynamic fairing and prop spinner tests?

not at all...

;-)

Nige's idea about making something from say OSB and lining it with
some DPM or pond liner could be a good compromise as it could be made
fairly cheaply and fairly easily (it could be stitched together using
cable ties) and then flat-packed or reused for other roles if / when
the project was over.

Square (or rectangular) would be the easiest and possibly the most
self supporting (square corners), the top edges could be stiffened
with a bit of batten (and / or the outboard supporting frame) and a
circular inner wall could be formed inside the liner, to manage the
water flow if required.

Or truly round, using cooper techniques: tongue-and-groove boards, i.e. decking,
cheap paneling? Plain boards, and ratchet straps around the outside?

Wow, that would be a project and probably require more patience than
I've got! When you say that a hot tub comes to mind ...


1 x 11 x 1220 x 2440mm (£15) for the base and two sides and another
for the remaining two sides and maybe some inner corners to make an
octagon plus 20 quid for 3 x m of DPM? A bag of cable ties to stitch
it all together or some lightish line?

Ratchet straps, which are also useful in other ways, afterwards.

True and I already have plenty of them. I still think the corners
might appreciate being held together, at least initially, along with
the sides being held to the bottom, till it's filled with water? Easy
to do with some cord stitching. Just lay each section against it's
partner and drill though both with say a 10mm bit. Then you just run a
line (or releasable cable ties) though each hole to 'stitch it
together into the basic shape. Add liner and water and you are away
and nothing is going anywhere. Add the 45 degree corner sections to
make the octagon and you wouldn't need the liner to make it circular
and it would brace the sides so you don't need the straps. ;-)

I was thinking on that if I wanted to slow the water circulation speed
/ apply some (more) load to the motor I could just build a weir under
the water (engineering bricks?) maybe 90 degrees behind the position
of the outboard around the tank?

Or just stand in the tank!

Hehe! ;-)

Cheers, T i m

p.s. I Googled your 'John Azur' outboard and they look like they might
be quite old? I do like the design of the underwater unit though,
especially how they return the diameter of the motor housing down to
that of the prop and then get close to the diameter of the prop (so
not having a central hub etc).

I note it also has the tubular pole connecting the underwater head to
the rest and I think I understand that a tubular section has 5 times
the drag of an aero/hydro-foil of the same diameter. Now, I know these
outboards don't go though the water at the same speed as many IC
outboard but at the same time we would be looking to maximise the
efficiency of what little power we have available. The lower leg of
most IC outboards are have a hydro dynamically efficient shape.

So, because I have a 3 printer and like to play, I was going to design
and print some clamshell type 'trims' to add to the lower leg to both
help with the hydrodynamics and with the steering (it acting like a
small rudder when the motor is off).

"Thomas Prufer" wrote in message
news
On Wed, 23 Aug 2017 23:24:54 +0100, T i m wrote:

It is a Yamaha M12 (re badged Minn Kota) electric outboard or
'trolling motor' as they call them in The States and gives about 30lb
thrust on full.

Please let me know how you get on.

I have an electric outboard ("John Azur"), and a PWM controller from
China,
presently awaiting tuits...

I've also looked at this and its brothers:
"Digital LCD DC combo Meter Watt Power Volt Amp RC Battery dis charging
Analyzer" http://r.ebay.com/RQX0Go

which does current times voltage over time, and could work as a "fuel
gauge"...

If you want to see what's possible -- look for "Torqueedo" outboards. They
have
an accurate range estimate in miles in their system, using a GPS. (Note:
for the
price, you will be ble to hire someone to paddle you upstream for a week).

As to the tank -- Dunno about round, and the water moving in a circle: the
watter current would speed up, dropping the electric current, and the
water
would start to climb up the sides of a circular container, and the
outboard
might start to move to the side and the propeller hit the container wall.

44gal drum works fine with much bigger outboards than that.

Turbulent flow would provide a more constant load.

Other than that: rainwater butt? Inflatable pool? a "Fast set pool", 8 ft
diam
for 30 quid (which would required external support for the motor)?

Or, here, I'd be looking at mortar pans, like he bit small, but very
cheap
http://www.hornbach.de/shop/Moertelkuebel-PE-rund-90-Liter/274271/artikel.html


Thomas Prufer

On Thu, 24 Aug 2017 10:42:23 +0100, T i m wrote:



Nige's idea about making something from say OSB and lining it with
some DPM or pond liner could be a good compromise as it could be made
fairly cheaply and fairly easily (it could be stitched together using
cable ties) and then flat-packed or reused for other roles if / when
the project was over.

Square (or rectangular) would be the easiest and possibly the most
self supporting (square corners), the top edges could be stiffened
with a bit of batten (and / or the outboard supporting frame) and a
circular inner wall could be formed inside the liner, to manage the
water flow if required.

Coming back in again , if you are going to line it with pond liner
would a collapsible compost bin make a good start and save a lot of
work?

something like this
https://i.ebayimg.com/00/s/NTMzWDQxNg==/z/bxoAAOSwepZXTFv8/$_86.JPG

I've seen square ones as well.

G.Harman

In message , T i m
writes
On Thu, 24 Aug 2017 09:28:49 +0100, Tim Lamb
wrote:
and a large domestic header tank going in the
next scrap skip.

Thanks for the thoughts and offer Tim. Are we talking a traditional
rectangular water (rather than CH header) galv tank here ... (as you
mentioned the scrap skip) or plastic? If it's plastic and one of the
larger sizes I'd like to consider the dimensions and see if I can do
something with it please?

Huh! Farms have waste plastic issues.

It's big!. 1.1mL x 500mmW x 800mmD

--
Tim Lamb

On Thu, 24 Aug 2017 10:59:48 +0100, wrote:

On Thu, 24 Aug 2017 10:42:23 +0100, T i m wrote:



Nige's idea about making something from say OSB and lining it with
some DPM or pond liner could be a good compromise as it could be made
fairly cheaply and fairly easily (it could be stitched together using
cable ties) and then flat-packed or reused for other roles if / when
the project was over.

Square (or rectangular) would be the easiest and possibly the most
self supporting (square corners), the top edges could be stiffened
with a bit of batten (and / or the outboard supporting frame) and a
circular inner wall could be formed inside the liner, to manage the
water flow if required.

Coming back in again ,

Welcome back. ;-)

if you are going to line it with pond liner

Well, I can, if the structure isn't waterproof etc ...

would a collapsible compost bin make a good start and save a lot of
work?

something like this
https://i.ebayimg.com/00/s/NTMzWDQxNg==/z/bxoAAOSwepZXTFv8/$_86.JPG

Oooh, now that looks interesting, unless I could find a second hand
one they don't look cheap though:

http://www.gardeningdelights.com/the...-komp-700.html

I've seen square ones as well.

I think the hex one would be the best option but after Googling around
I saw a round composter made from a wire mesh. Given that I could line
something with DPM to make it waterproof, maybe a wire ring with a
semi rigid sheet and then the liner might be ok?

Cheers, T i m

On Thu, 24 Aug 2017 13:06:04 +0100, Tim Lamb
wrote:

In message , T i m
writes
On Thu, 24 Aug 2017 09:28:49 +0100, Tim Lamb
wrote:
and a large domestic header tank going in the
next scrap skip.

Thanks for the thoughts and offer Tim. Are we talking a traditional
rectangular water (rather than CH header) galv tank here ... (as you
mentioned the scrap skip) or plastic? If it's plastic and one of the
larger sizes I'd like to consider the dimensions and see if I can do
something with it please?

Huh! Farms have waste plastic issues.

Ah. ;-(

It's big!. 1.1mL x 500mmW x 800mmD

Thanks for that. I'm not sure I can get the water path (up and back
etc) in the 500mm so I think I'll pass for now if that's ok.

I would have thought you would have been littered with those IBC
tanks, for your wine deliveries if nothing else ducks ;-)

Cheers, T i m

In message , T i m
writes
On Thu, 24 Aug 2017 13:06:04 +0100, Tim Lamb
wrote:
It's big!. 1.1mL x 500mmW x 800mmD

Thanks for that. I'm not sure I can get the water path (up and back
etc) in the 500mm so I think I'll pass for now if that's ok.

I would have thought you would have been littered with those IBC
tanks, for your wine deliveries if nothing else ducks ;-)

They used to be worth £60.00. The only one I have left is half full of
waste oil!

The garden grape vines are yielding nicely this year:-) Usually
converted to grape jelly.

--
Tim Lamb

On Thu, 24 Aug 2017 17:51:00 +0100, Tim Lamb
wrote:

In message , T i m
writes
On Thu, 24 Aug 2017 13:06:04 +0100, Tim Lamb
wrote:
It's big!. 1.1mL x 500mmW x 800mmD

Thanks for that. I'm not sure I can get the water path (up and back
etc) in the 500mm so I think I'll pass for now if that's ok.

I would have thought you would have been littered with those IBC
tanks, for your wine deliveries if nothing else ducks ;-)

They used to be worth £60.00.

Good cleaned ones can still be found at those prices and the smaller
ones (500L) are more so.

When you buy whatever normally comes in them (I know of PVA glue, car
polish, something to do with printing, jam?) do you normally have to
pay 'on top' for the IBC or is it incorporated in the price of the
product?

Are any re-cycled by the suppliers (by default)?

The only one I have left is half full of
waste oil!

All types?

The garden grape vines are yielding nicely this year:-)

Excellent ... and from memory there were quite a few!

Usually
converted to grape jelly.

Is that what you call it hic!. ;-)

Cheers, T i m

On Thu, 24 Aug 2017 19:11:11 +0100, T i m wrote:

On Thu, 24 Aug 2017 17:51:00 +0100, Tim Lamb
wrote:
r now if that's ok.

I would have thought you would have been littered with those IBC
tanks, for your wine deliveries if nothing else ducks ;-)

They used to be worth £60.00.

Good cleaned ones can still be found at those prices

£35 for a good clean one that had held a detergent/disinfectent bought
this spring.

seller is still listing them at that price
http://www.ebay.co.uk/itm/Ibc-Contai...AOSwTM5YxRn Y

only thing to watch for is mine came with the finer thread rather than
the more common coarse one but that would only matter if you wanted
to put a pipe connection or different tap on the outlet. Both sizes
are easily obtained but pays to wait until you know what you have.

G.Harman

On Thu, 24 Aug 2017 10:42:23 +0100, T i m wrote:

p.s. I Googled your 'John Azur' outboard and they look like they might
be quite old? I do like the design of the underwater unit though,
especially how they return the diameter of the motor housing down to
that of the prop and then get close to the diameter of the prop (so
not having a central hub etc).


Yes, old. Cheap used:-) Goes with the "Faltboot", a used one cheap from the
early 70's. The motor is mostly metal, the switch bakelite, and pretty basic and
robust.


I note it also has the tubular pole connecting the underwater head to
the rest and I think I understand that a tubular section has 5 times
the drag of an aero/hydro-foil of the same diameter. Now, I know these
outboards don't go though the water at the same speed as many IC
outboard but at the same time we would be looking to maximise the
efficiency of what little power we have available. The lower leg of
most IC outboards are have a hydro dynamically efficient shape.

There's only about 3" or so of the pole in the water. The motor in mounted on a
wooden bar across the transom, off to the side of the boat. This is similar to
the sail and leeboard holder, only sticks out more on one side.

Have look at http://www.faltbootbasteln.de/fbb-tuemmler.html, which describes
an East German sideboard two-stroke motor, popular back then.

And on ebay there was a wonderful sideboard motor from 1920 or so, more than
complete, original box, original tools, extra spares. Same model some guy had
used in Arctic waters in a folding fabric boat. And I would have bought it, damn
the expense, but combustion engines on water a heavily regualted here, and
two-strokes a nono...

Or this, another diy/East German thing:

http://pf31.pappenforum.de/thread/22...141#post272141

Combined rudder and motor...


So, because I have a 3 printer and like to play, I was going to design
and print some clamshell type 'trims' to add to the lower leg to both
help with the hydrodynamics and with the steering (it acting like a
small rudder when the motor is off).

Have a look at this propeller guard for the John Azur:

https://www.ebay-kleinanzeigen.de/s-...69773-211-1811


Thomas Prufer

In message , T i m
writes
On Thu, 24 Aug 2017 17:51:00 +0100, Tim Lamb
wrote:

In message , T i m
writes
On Thu, 24 Aug 2017 13:06:04 +0100, Tim Lamb
wrote:
It's big!. 1.1mL x 500mmW x 800mmD

Thanks for that. I'm not sure I can get the water path (up and back
etc) in the 500mm so I think I'll pass for now if that's ok.

I would have thought you would have been littered with those IBC
tanks, for your wine deliveries if nothing else ducks ;-)

They used to be worth £60.00.

Good cleaned ones can still be found at those prices and the smaller
ones (500L) are more so.

When you buy whatever normally comes in them (I know of PVA glue, car
polish, something to do with printing, jam?) do you normally have to
pay 'on top' for the IBC or is it incorporated in the price of the
product?

They used to come here full of mashed up barley. A by-product of the
brewing/distillery industry. Poured on to barley straw to encourage
housed cattle to eat an otherwise unpalatable feed.

Are any re-cycled by the suppliers (by default)?

The empty would be exchanged for a full one. Left overs occur when the
cattle are turned out to graze or sold off the farm. The deposit can
then only be recovered by sale.


The only one I have left is half full of
waste oil!

All types?

Umm... agricultural? Mix of engine oil and hydraulic fluid plus a fair
bit of water at the bottom.

The garden grape vines are yielding nicely this year:-)

Excellent ... and from memory there were quite a few!

Usually
converted to grape jelly.

Is that what you call it hic!. ;-)

Cheers, T i m




--
Tim Lamb

On Thu, 24 Aug 2017 21:35:15 +0200, Thomas Prufer
wrote:

On Thu, 24 Aug 2017 10:42:23 +0100, T i m wrote:

p.s. I Googled your 'John Azur' outboard and they look like they might
be quite old? I do like the design of the underwater unit though,
especially how they return the diameter of the motor housing down to
that of the prop and then get close to the diameter of the prop (so
not having a central hub etc).


Yes, old. Cheap used:-)

As long as it was also 'loved', old and used can be fine. ;-)

Goes with the "Faltboot", a used one cheap from the
early 70's.

Do you have a link to what you have as there may be different
versions?

The motor is mostly metal, the switch bakelite, and pretty basic and
robust.

It looks it. ;-)


I note it also has the tubular pole connecting the underwater head to
the rest and I think I understand that a tubular section has 5 times
the drag of an aero/hydro-foil of the same diameter. Now, I know these
outboards don't go though the water at the same speed as many IC
outboard but at the same time we would be looking to maximise the
efficiency of what little power we have available. The lower leg of
most IC outboards are have a hydro dynamically efficient shape.

There's only about 3" or so of the pole in the water.

Understood, however, I understand that if you were to put foil section
over it would reduce the effective diameter to 1/5th.

On my Seahopper Kondor I think there is more of the pole in the water
but some of it may be masked by the square transom.

The motor in mounted on a
wooden bar across the transom, off to the side of the boat.

I have an ally version of the same thing.

This is similar to
the sail and leeboard holder, only sticks out more on one side.

Understood.

Have look at http://www.faltbootbasteln.de/fbb-tuemmler.html, which describes
an East German sideboard two-stroke motor, popular back then.

Neat. It reminds me of the ex car engined powered longboats you see in
the Far East and Africa etc.

And on ebay there was a wonderful sideboard motor from 1920 or so, more than
complete, original box, original tools, extra spares. Same model some guy had
used in Arctic waters in a folding fabric boat.

I love the whole 'folding' concept (we also have a 12' Porta-Bote
(American) and a Rapido Confortmatic folding caravan (French)). ;-)

And I would have bought it, damn
the expense, but combustion engines on water a heavily regualted here, and
two-strokes a nono...

We are seeing some of that here.

Or this, another diy/East German thing:

http://pf31.pappenforum.de/thread/22...141#post272141

Combined rudder and motor...

That was the sort of side effect I was envisaging when adding a foil
section to the bottom of the Minn Kota. That one looks like the
steering might be quite 'heavy' with the pivot so far away from the
prop?


So, because I have a 3 printer and like to play, I was going to design
and print some clamshell type 'trims' to add to the lower leg to both
help with the hydrodynamics and with the steering (it acting like a
small rudder when the motor is off).

Have a look at this propeller guard for the John Azur:

https://www.ebay-kleinanzeigen.de/s-...69773-211-1811

Yeah, I saw those on some motors when I first Googled for the 'John
Azur'. I assume it might not only protect the prop but make the
steering more direct and possibly the drive more efficient (less water
spilled off the side of the prop)?

I ran my 40A PWM controller against a 60W headlamp for a while this
afternoon, just to check that it worked and see how warm the
controller got. It did warm up a bit so I might need to consider some
form of fan cooling if I'm running it at 15-30A for prolonged periods.

This one was a reversing model and I assumed (incorrectly) it would
use an output bridge. So I also bought a pair of HD C/U relays to make
my own reversing solution on a straight Fwd only controller (that
would only pull in when reverse was selected). However, I found the
one I bought also used relays for the reverse but it seems one pulls
in when Fwd is selected and then the other when in Rev?

Because the amount of time it would be in reverse would be tiny, I
would have thought only pulling the relays in when required would be
more efficient? Have I overlooked something with this one for each
direction solution?

I was also wondering if simple prop revs (in the same water tank)
would be sufficient to measure the straight / PWM comparison (no good
for the prop / leg mods etc).

Cheers, T i m

On Thu, 24 Aug 2017 20:08:56 +0100, wrote:

On Thu, 24 Aug 2017 19:11:11 +0100, T i m wrote:

On Thu, 24 Aug 2017 17:51:00 +0100, Tim Lamb
wrote:
r now if that's ok.

I would have thought you would have been littered with those IBC
tanks, for your wine deliveries if nothing else ducks ;-)

They used to be worth £60.00.

Good cleaned ones can still be found at those prices

£35 for a good clean one that had held a detergent/disinfectent bought
this spring.

Yeah, I saw a lot at that price but was suggesting to Tim there were
still some being sold for double that. ;-)

seller is still listing them at that price
http://www.ebay.co.uk/itm/Ibc-Contai...AOSwTM5YxRn Y

That looks ideal (at that price) but would cost more in petrol (for
me) than something local but more expensive. ;-)

only thing to watch for is mine came with the finer thread rather than
the more common coarse one but that would only matter if you wanted
to put a pipe connection or different tap on the outlet. Both sizes
are easily obtained but pays to wait until you know what you have.

Thanks for the heads up.

I was thinking of getting one where I could roughly cut it down whilst
I was there (battery electric jigsaw with metal cutting blade for the
cage and a panel saw for the tank) and then I should be able to get it
all in the back of the Meriva?

Do you think a jigsaw would be ok on the frame or would a hand saw be
better?

Cheers, T i m

On Thu, 24 Aug 2017 20:48:15 +0100, Tim Lamb
wrote:

snip

When you buy whatever normally comes in them (I know of PVA glue, car
polish, something to do with printing, jam?) do you normally have to
pay 'on top' for the IBC or is it incorporated in the price of the
product?

They used to come here full of mashed up barley. A by-product of the
brewing/distillery industry.

Would one have to pay for that or are they simply getting rid of what
they see as waste?

Poured on to barley straw to encourage
housed cattle to eat an otherwise unpalatable feed.

Yum. ;-)

Are any re-cycled by the suppliers (by default)?

The empty would be exchanged for a full one.

Ah, so as long as you keep that cycle going etc ...

Left overs occur when the
cattle are turned out to graze or sold off the farm.

Ok.

The deposit can
then only be recovered by sale.

Ah.


The only one I have left is half full of
waste oil!

All types?

Umm... agricultural? Mix of engine oil and hydraulic fluid plus a fair
bit of water at the bottom.

Ok, thanks (wasn't sure if you could also add cooking oil etc).

Cheers, T i m

On Thu, 24 Aug 2017 21:24:47 +0100, T i m wrote:

Do you have a link to what you have as there may be different
versions?

Possibly hundreds of versions. It was a big thing in Germany, starting about
1920.

http://www.faltbootbasteln.de/fbb-me...hammer-fb.html

Understood, however, I understand that if you were to put foil section
over it would reduce the effective diameter to 1/5th.

On my Seahopper Kondor I think there is more of the pole in the water
but some of it may be masked by the square transom.

That's why I would guess that reducing the drag of the pole is irrelevant --
because it is a small part of the total.

But two-three airfoil-shaped plates, and a bit of flexible plastic to wrap it
around, and a large tank to test it would put some facts up against my guess!


That was the sort of side effect I was envisaging when adding a foil
section to the bottom of the Minn Kota. That one looks like the
steering might be quite 'heavy' with the pivot so far away from the
prop?

Possibly. I think I saw a DIY version with the motor closer to the rudder shaft,
on ebay, but it went for lot more than I was prepared to pay for it.

And these rudders are at the back, and moved by two cables and foot pedals, so
it's easy to put a lot of force on the rudder.


Yeah, I saw those on some motors when I first Googled for the 'John
Azur'. I assume it might not only protect the prop but make the
steering more direct and possibly the drive more efficient (less water
spilled off the side of the prop)?

It should, but it would also increase the drag. OTOH, weeds wrapped around the
prop increase the drag, too!

I ran my 40A PWM controller against a 60W headlamp for a while this
afternoon, just to check that it worked and see how warm the
controller got. It did warm up a bit so I might need to consider some
form of fan cooling if I'm running it at 15-30A for prolonged periods.

Avoid fans if you can, and just use large heatsinks instead. Plenty for free if
you can get at skipped computers. Or unsolder the hot components, and wire them
to the inside of a metal housing. Fans clog, make noise, and provide hole for
water to get in.

This one was a reversing model and I assumed (incorrectly) it would
use an output bridge. So I also bought a pair of HD C/U relays to make
my own reversing solution on a straight Fwd only controller (that
would only pull in when reverse was selected). However, I found the
one I bought also used relays for the reverse but it seems one pulls
in when Fwd is selected and then the other when in Rev?

Because the amount of time it would be in reverse would be tiny, I
would have thought only pulling the relays in when required would be
more efficient? Have I overlooked something with this one for each
direction solution?

The relay won't use much power, not compared to the draw of the motor.

Maybe use the spare relay to disconnect the PWM when off, and to connect the
motor directly to the battery for "full speed ahead". My PWM says it draws power
even when off, and while the few mA are irrelevant during use, they will
needlessly drain the battery during storage -- some sort of "true off" that
can't be forgotten is nice. Though I was planning to use fat clips attached to
the battery terminals, and unclipping would happen when lifting the battery out.

I was also wondering if simple prop revs (in the same water tank)
would be sufficient to measure the straight / PWM comparison (no good
for the prop / leg mods etc).

You'll probably end up with some sort of force measuring arrangement anyway.

Scale, or measuring the torsion of some sort of mounting bar...

Thomas Prufer

On Fri, 25 Aug 2017 08:41:40 +0200, Thomas Prufer
wrote:

On Thu, 24 Aug 2017 21:24:47 +0100, T i m wrote:

Do you have a link to what you have as there may be different
versions?

Possibly hundreds of versions. It was a big thing in Germany, starting about
1920.

http://www.faltbootbasteln.de/fbb-me...hammer-fb.html

Thanks for that.

Understood, however, I understand that if you were to put foil section
over it would reduce the effective diameter to 1/5th.

On my Seahopper Kondor I think there is more of the pole in the water
but some of it may be masked by the square transom.

That's why I would guess that reducing the drag of the pole is irrelevant --
because it is a small part of the total.

But still part of the total and may be a more relevant improvement if
I use it with say my 16' Canadian canoe?

But two-three airfoil-shaped plates, and a bit of flexible plastic to wrap it
around, and a large tank to test it would put some facts up against my guess!

Easier for me to 3D print it Thomas g and as I said, may give me a
better rudder effect when the motor is off (especially).


That was the sort of side effect I was envisaging when adding a foil
section to the bottom of the Minn Kota. That one looks like the
steering might be quite 'heavy' with the pivot so far away from the
prop?

Possibly. I think I saw a DIY version with the motor closer to the rudder shaft,
on ebay, but it went for lot more than I was prepared to pay for it.

And these rudders are at the back, and moved by two cables and foot pedals, so
it's easy to put a lot of force on the rudder.

Understood. However, I still think it looks like it would try to
'flop' to one side or the other, rather than being balances around the
centre of effort?


Yeah, I saw those on some motors when I first Googled for the 'John
Azur'. I assume it might not only protect the prop but make the
steering more direct and possibly the drive more efficient (less water
spilled off the side of the prop)?

It should, but it would also increase the drag.

True.

OTOH, weeds wrapped around the
prop increase the drag, too!

As do plastic bags etc. ;-(

I ran my 40A PWM controller against a 60W headlamp for a while this
afternoon, just to check that it worked and see how warm the
controller got. It did warm up a bit so I might need to consider some
form of fan cooling if I'm running it at 15-30A for prolonged periods.

Avoid fans if you can, and just use large heatsinks instead. Plenty for free if
you can get at skipped computers.

I already have plenty of salvaged heatsinks. ;-)

Or unsolder the hot components, and wire them
to the inside of a metal housing.

The only problem with that is checking that the tags are either
isolated or making sure they are isolated from any heatsink and the
resistance of the cables joining the output devices back to the PCB.
Where you see output devices heatsinked away from the PCB they are
normally soldered to the edge of the board so they can just be bent
over without adding extra cables. That's not to say 'remoting' the
output devices wouldn't be worth doing, just that we are back down to
compromises.

Fans clog, make noise, and provide hole for
water to get in.

Agreed, but less so when used in a dinghy (clog), it would be a larger
fan speed controlled to be quiet and I would make it rain proof. If it
ever got immersed I would probably have more pressing issues than an
£8 PWM controller getting wet! ;-(

This one was a reversing model and I assumed (incorrectly) it would
use an output bridge. So I also bought a pair of HD C/U relays to make
my own reversing solution on a straight Fwd only controller (that
would only pull in when reverse was selected). However, I found the
one I bought also used relays for the reverse but it seems one pulls
in when Fwd is selected and then the other when in Rev?

Because the amount of time it would be in reverse would be tiny, I
would have thought only pulling the relays in when required would be
more efficient? Have I overlooked something with this one for each
direction solution?

The relay won't use much power, not compared to the draw of the motor.

Agreed, I think I measured it (on my Wattmeter) as 50ma.

Maybe use the spare relay to disconnect the PWM when off, and to connect the
motor directly to the battery for "full speed ahead".

Funnily enough, that's what we did on the electronic 'speedo' we
designed for electric RC car racing some 40+ years ago. The supplied
speed controller used 5 micro switches on a cam, 3 to progressively
short out series resistors (in series with the motor) and the last two
to give reverse (plus the others still). Our electro-mechanical one
used a 2N3055 as the output transistor and a relay to short it out at
full speed. ;-)

My PWM says it draws power
even when off, and while the few mA are irrelevant during use, they will
needlessly drain the battery during storage -- some sort of "true off" that
can't be forgotten is nice.

Understood.

Though I was planning to use fat clips attached to
the battery terminals, and unclipping would happen when lifting the battery out.

I get similar results on my existing (60Ah) battery. I have a couple
of m of *very* heavy (but flexible) cable merging into some thinner
(16^2mm) at the end going into an Anderson SB50 connector. I cut the
end of the lead with the terminals off the outboard when I first got
it and fitted an SB50 to that, and to the original end as a backup. I
have a 50A resettable fuse on the +12 at the battery end. Now I'm
going to replace (or supplement) the single 60Ah battery with 2 or 3
smaller (~40Ah) batteries I will probably just fit the new batteries
with a resettable fuse and a short 16^2mm 'tail' to a SB50 and have a
~2m extension lead of a similar size so I can keep the batteries in
the bow. The PWM controller / Wattmeter can then be inserted in the
SB50 connection at the outboard end.

I was also wondering if simple prop revs (in the same water tank)
would be sufficient to measure the straight / PWM comparison (no good
for the prop / leg mods etc).

You'll probably end up with some sort of force measuring arrangement anyway.

Hmmmm ...

Scale, or measuring the torsion of some sort of mounting bar...

I wasn't sure if there was enough of a direct relationship between
outboard force versus hull speed but it might be an easier way of
taking an output effort measurement so I can compare pre / post PWM
control (at least). Thanks. ;-)

Cheers, T i m

On Fri, 25 Aug 2017 09:05:58 +0100, T i m wrote:

Understood. However, I still think it looks like it would try to
'flop' to one side or the other, rather than being balances around the
centre of effort?

I doubt it... The East Germans couldn't travel much (at least to places they
wanted to go) and did a lot of diy and furtling and making-do, and some of that
was amazingly ingenious. (Some of it was complete crap, often reinventing the
wheel poorly, mostly because something wasn't available, i.e. electronic
circuits...) And something like that is easily furtled.

Have a look at these, both East German, both still available on ebay:

http://www.faltbootbasteln.de/fbb-tuemmler.html
http://www.faltbootbasteln.de/fbb-zu...tenborder.html

Thomas Prufer

wrote:
On Wed, 23 Aug 2017 18:11:21 +0100, T i m wrote:

Hi all,

I'm looking for a 'tank' to test the performance of a small electric
outboard, (PWM speed controllers, batteries, hydrodynamic
slipstreaming mods etc) so am thinking of a circular tank,

So, after a bit of Googling I came across the IBC water containers and
1) wondered if anyone knows where there might be one that still holds
water (at least over the lower half) near Nth London that someone
might like to see the back of and 2) if you think it might be suitable
for my needs please (or if not, why not etc). If not there seem to be
plenty on eBay cheap enough.

A concern may how much strength there will be left once to top is cut
off though the one I have seems fairly heavy gauge material and you
still have the reinforcing cage to help with that, but you may have to
cut that down as well.


Would it being nearly square (all be it with round corners) with maybe
something in the middle to ensure water actually flows 'round' the
container be free moving enough or do you think I'd need to fit a
round liner inside it?

If the bottom (inside) isn't flat or couldn't easily be made flattish
(from a water flow POV) could I use the top half upturned instead (I
could fit my own drain cock etc).

The bottom is fairly flat apart from a section a bit lower for the
tap.

To satisfy the above concerns it would seem like a lot of kerfuffle to
do rather than but a round tank in the first place from a suppler like
an agricultural merchant.


How much depth do you need? I've seen an instant garden water feature
made by using a section of concrete pipe lined with an off cut of pond
liner , the latter can often be found as remnants at water garden
supplies but for intermittent use a bit of DPC membrane should
suffice. As would doing the same with a large truck or tractor tyre
but that could lead to disposal problems later.


Any other ideas around the above welcome of course. ;-)


If you go down the IBC route what it originally had in it may have a
bearing, mine had contained a detergent that was for washing
supermarket food crates so rinsed clean easily, some that tend be at
the cheaper end of prices asked have had things like fibre glass resin
in which is harder to deal with for some applications.

You can also get half size 500l ones but being rarer and sough after
tend to actually cost more.


G.Harman


Why not use the local canal?

On Fri, 25 Aug 2017 17:20:34 +0100, Capitol wrote:

snip

Why not use the local canal?

We can / will (as well), but it's much easier (considering) and
probably cheaper all round, to be able to do it at home, at least
first.

e.g. To book a day ticket on the Lea for a small motorboat is about 16
quid on the day (it might be cheaper if done in advance) and if it all
goes wrong within the first 10 seconds then that, along with getting
the boat and other gear out, in / on the car, down to the river and
launched makes for a bit of waste of time, effort and money. ;-(

Then you have the weather ... open electronics and DMM's don't
generally like the rain (and nor do we). ;-)

Lastly there is the opportunity. It is much easier to grab some time
here and there than it is to take the boat to the river.

However, once I have done whatever tests I can do at home (and some
may take some time, like real-world battery run-time tests on the
outboard in the test tank) and have suitably packaged any electronics
etc, I will be able to continue monitoring and fine tuning on the
river. ;-)

Cheers, T i m

On Thu, 24 Aug 2017 13:06:04 +0100, Tim Lamb
wrote:

In message , T i m
writes
On Thu, 24 Aug 2017 09:28:49 +0100, Tim Lamb
wrote:
and a large domestic header tank going in the
next scrap skip.

Thanks for the thoughts and offer Tim. Are we talking a traditional
rectangular water (rather than CH header) galv tank here ... (as you
mentioned the scrap skip) or plastic? If it's plastic and one of the
larger sizes I'd like to consider the dimensions and see if I can do
something with it please?

Huh! Farms have waste plastic issues.

It's big!. 1.1mL x 500mmW x 800mmD

Hi Tim, you know how things come to you in your sleep ...has the skip
been collected yet please? ;-(

Thinking that at least for some initial load / PWM V resistor speed
control tests and potentially the hydrodynamic improvements to the leg
and prop ... that for the outboard to be running under similar
conditions to it being on the back of a boat ... eg, with water
flowing past the prop rather than just turbulating around it in a
dustbin etc?

.... What if rather than the water flowing round a circular pool with
something in the middle to ensure there was a flow, the shape of a
doughnut ... what if the flow was horizontal, along a top layer in the
tank, down the end, back underneath and up and along again. ;-)

e.g. If I took something like your tank that is fairly narrow,
reasonably long and fairly deep and put say a (600x600) concrete slab
(trimmed to 600 x 500) just off the bottom on some ledges or short
legs, as long as there was roughly the same size gap at each end of
the slab as it was from the bottom (say 200mm) and the outboard in
sufficient depth of water above it, I should be good to go! If I
wanted to make the water flow slightly more laminar, half a cylinder
across either end (water butt?) would help deflect the water down and
round etc. ;-)

And being the size the tank is it should fit easier in the Meriva than
an IBC tank and take up less room when in action.

Because it's not too wide I should also have room either side to
fabricate a wooden frame that would allow the outboard to pivot and a
bar extended upwards the same distance from the centre of the prop to
the pivot should give me somewhere to fit a scale to measure the
thrust. ;-)

Assuming you still have the tank and are happy for me to have it, want
to swap it for some fish and chips (or summat. I'll p.m you the
timescales etc)?

Cheers, T i m

On 24/08/2017 21:24, T i m wrote:
On my Seahopper Kondor I think there is more of the pole in the water
but some of it may be masked by the square transom.

Then you need to sit further forward.

Immersed transoms are bad news. They're only good when you get towards
planing speed (I could explain, but it's complicated). Ask any racing
sailor.

Andy

On Mon, 28 Aug 2017 21:52:28 +0100, Vir Campestris
wrote:

On 24/08/2017 21:24, T i m wrote:
On my Seahopper Kondor I think there is more of the pole in the water
but some of it may be masked by the square transom.

Then you need to sit further forward.

The dual purpose transom carries both the gudgeons for the rudder and
allows the outboard to be offset slightly (avoiding the gudgeons).
This means the prop is also out of the turbulence of the skeg but
still has to be set low enough to ensure the prop can't hit the skeg
on full lock (as the prop is a fair way back from the 'leg / tube').
This is good in that the prop is away from floating weeds and less
chance of the prop breaking the surface during waves / wash and puts
it in a fairly clean flow of water from under the hull. The head of
the outboard still sticks up over the transom quite a bit, even though
it's the short shaft model.

Anyroadup, being the son of a Master Mariner and so spending most of
my life in boats, I believe I have a reasonable idea how to trim a
boat (but thanks for the heads up). ;-)

For example ... in the 3m Kondor, the 17kg battery was just behind the
bow seat, the Mrs was on the centre thwart on the Port side and I
would nearly be on the centre thwart on the Starboard side bench. The
only thing behind me would be the (very light) outboard. ;-)

Immersed transoms are bad news.

Quite ... and luckily the Seahopper Kondor has reasonable rocker so
not that much of the transom would be submerged, under those
conditions.

They're only good when you get towards
planing speed (I could explain, but it's complicated). Ask any racing
sailor.

Like me you mean (well, a sailor who has raced and really enjoys
sailing his 14' dinghy single handed in a breeze for the fun of
planing everywhere)? ;-)

Dad entered a non sailor mate who was on holiday with us and I in an
open handicap race on Oulton Broad when I was about 16. We just had
time to get my 14' Leader rigged, launched and up to the start line,
along with about 60 other boats. gulp

One race later and it turns out we came 3rd! The guys in the Merlin
Rocket we sailed past asked if we had an electric motor or something.
;-)

I'd not been sailing for about 10 years (and then 60 years old) when
we took the Seahopper Kontender to a local sailing club for our first
time / shakedown sail and as 'guests'. We were only allowed on the
water (as guests) when the rescue boat was out and that was only out
when the racing was on. So, we went out during the first race,
generally went the same way round as them but kept out of their way.
When the race was finished the guys in the rescue boat (who had
attended about 50% of the fleet when they capsized) suggested we
looked like 'the most stable boat out there' and 'would we like to
enter the race in the afternoon?' blush

Apart from not really being interested in racing but (it's been
suggested I am a reasonable sailor), I don't think there is a
yardstick rating for a Kontender / Kondor, not am I insured for racing
in any case.

When rowing two up and even with all the gear, the 17.5 Kg battery,
electric outboard dismounted and as far forward as possible, it's
trimmed slightly bow up. Being I row for exercise and fun and the
Seahoppers having a pram bow, depending on the load it's a balancing
act to just keep the bottom of the pram bow out of the water and not
have the turbulence from the submerged transom. One up with an
otherwise empty boat she skitters about easily (considering she's a
folding boat etc).

Now, if I really wanted to row something nice I have a 14' clinker
pattern, GRP Thames rowing skiff in my lockup and that has a proper
displacement hull (fine stem at the bow with 'S' bottom at the stern),
ideally setup for rowing. Unfortunately it won't fold flat to be
carried on the roof of the car nor hang in the roof of the garage at
home. ;-(

Cheers, T i m

https://www.seahopperfoldingboats.co...r9-400x400.jpg
https://www.seahopperfoldingboats.co...opper-row7.jpg

On 28/08/2017 23:34, T i m wrote:
Like me you mean (well, a sailor who has raced and really enjoys
sailing his 14' dinghy single handed in a breeze for the fun of
planing everywhere)?;-)

My apologies. I assumed you were purely a stink boat man...

I have a Solo.

Andy

On Tue, 29 Aug 2017 21:57:19 +0100, Vir Campestris
wrote:

On 28/08/2017 23:34, T i m wrote:
Like me you mean (well, a sailor who has raced and really enjoys
sailing his 14' dinghy single handed in a breeze for the fun of
planing everywhere)?;-)

My apologies.

None needed Andy. ;-)

I assumed you were purely a stink boat man...

Whilst I have done some hours in front of a British Seagull and a
little Yamaha 2hp 2/ outboard motors, I'm mainly a rowing / sailing /
cruising guy. ;-)


I have a Solo.

Nice. Very similar hull shape (hard chine) and could be the single
handed / sports version of the Leader (Solo PN:1140, Leader PN:1116,
so not miles apart). ;-)

The Leader (ours is composite) doesn't have side decks like the Solo
but the advantage of that (for cruising) is that it's very rowable and
very roomy. Also a tabernacle mast means it can easily be lowered from
inside the boat (handy for bridges) and having a solid transom means
it can also take a small outboard.

Only a tiny class compared with the Solo though so not very good for
single class racing (if that's your bag).

However, the battery / outboard question was for the little Seahopper
Kondor that I bought primarily because they row *much* better than the
Porta-Bote (I also have a 12' Gen IV) and can be sailed fairly well
(dagger board rather than lee boards etc) and sailing is my love.

When we can't get to The Broads (and I'm not really into the sea or
sailing round a small club lake), we can still row or electric
outboard up the Lea or similar.

Whilst the Kondor isn't the Leader when it comes to sailing, I can
store and transport it much easier and as a compromise solution, it
works very well. ;-)

Cheers, T i m

On 29/08/2017 23:17, T i m wrote:
Only a tiny class compared with the Solo though so not very good for
single class racing (if that's your bag).

That's it. I've done a little bit of cruising, but my wife always gets
frozen because I'm doing all the work... but I can go out on a Sunday
morning and have a good thrash around the pond with some like minded
guys, and still be home for tea.

We've considered a Broads cruiser. We've been in this part of the world
for 3 years now, and haven't got around to even renting one. Too much
time fixing the house. (We have evidence of bodges going back over 100
years, and it was only a peasant's cottage to start with.)

Though today the local uni reports 20kt gusts and a 6kt average. It was
a bit variable. I'll hurt tomorrow. I ache a bit now.

Andy

Huge wrote:
On 2017-09-03, Vir Campestris wrote:

[snippage]

We've considered a Broads cruiser.

The holiday we had on the Broads was the worst we ever had. After 3 days we took the boat back and went home. It was very like holidaying on the central reservation of the M1; noisy, dirty, crowded and almost entirely unpleasant.



WE used to go at Whitsun, it was very pleasant.