On Mon, 28 Aug 2017 19:47:55 +0100, T i m wrote:

On Mon, 28 Aug 2017 19:33:01 +0100, wrote:

snip

They tended to be too big for use on most UK canals. When Horses were
used as motive power they tended be something smaller both to fit
under the many low bridges and pass each other on the towpaths,


Didn't some bridges across rivers and canals gave a gap in the middle
Yes , some canals. Don't know of a river navigation . the Canals were
smaller ones so the bridge sections which were only supported at one
end need not be too large.
The canal to Stratford upon Avon was one and some bridges remain
though the gap has often been removed in recent decades so they can
stay up.
This one still has it.
http://racundra.puffinrock.co.uk/wp-...tford-1-17.jpg


so the horse drawn tow-rope could pass though as the horses crossed
sides?

But the gap wasn't solely for that reason, it was because there was
no towpath through the bridge at all so the horse would pass by the
bridge past the ends, sometimes they crossed other times they went
back down to the same side.
The better method for crossing from a towpath on one bank to another
was to use a what is called a roving bridge where the towpath crosses
the bridge and spirals back so the crossing is completed before the
horse passed through the arch. some of the more elaborate ones had a
seperate bridge on a bridge as seen here.
https://c2.staticflickr.com/4/3500/3...475c7d47_b.jpg



G.Harman

On Mon, 28 Aug 2017 23:00:17 +0100, wrote:

snip

Didn't some bridges across rivers and canals gave a gap in the middle
Yes , some canals. Don't know of a river navigation .

What about the River Lea (Navigation) (as opposed to the one that runs
parallel to it that isn't navigable)?

the Canals were
smaller ones so the bridge sections which were only supported at one
end need not be too large.

Ok.

The canal to Stratford upon Avon was one and some bridges remain
though the gap has often been removed in recent decades so they can
stay up.
This one still has it.
http://racundra.puffinrock.co.uk/wp-...tford-1-17.jpg

Nice pic, thanks. ;-)


so the horse drawn tow-rope could pass though as the horses crossed
sides?

But the gap wasn't solely for that reason, it was because there was
no towpath through the bridge at all so the horse would pass by the
bridge past the ends, sometimes they crossed other times they went
back down to the same side.

Ok, makes sense.

The better method for crossing from a towpath on one bank to another
was to use a what is called a roving bridge where the towpath crosses
the bridge and spirals back so the crossing is completed before the
horse passed through the arch. some of the more elaborate ones had a
seperate bridge on a bridge as seen here.
https://c2.staticflickr.com/4/3500/3...475c7d47_b.jpg

Wow, that is cool, thanks. ;-)

I'll show the daughter that and see if she can work out what it's for.

Cheers, T i m

On Mon, 28 Aug 2017 23:40:30 +0100, T i m wrote:

Didn't some bridges across rivers and canals gave a gap in the middle
Yes , some canals. Don't know of a river navigation .

What about the River Lea (Navigation) (as opposed to the one that runs
parallel to it that isn't navigable)?

What I meant was that I did not know of any fixed split bridge on a
River Navigation as opposed to a narrow canal, not that I did not know
of any river navigation's of which there are quite a few.
The Lea( Shouldn't it be Lee which differentiates it from the other?)
is quite wide and I don't think such a construction would suit.

Some commentators mention that the Stratford was unique in having them
but there is one about 15 miles away from me as I type and I'm sitting
in North Devon.
picture 25 on this gallery
http://www.bude-canal-trust.co.uk/main-gallery/
That has been strengthened in the 130 or so years since a the canal
closed but photo 9 in the same set shows recovered sections of
metalwork from another bridge nearby that no longer exists.

G.Harman

On Tue, 29 Aug 2017 01:04:57 +0100, wrote:

On Mon, 28 Aug 2017 23:40:30 +0100, T i m wrote:

Didn't some bridges across rivers and canals gave a gap in the middle
Yes , some canals. Don't know of a river navigation .

What about the River Lea (Navigation) (as opposed to the one that runs
parallel to it that isn't navigable)?

What I meant was that I did not know of any fixed split bridge on a
River Navigation as opposed to a narrow canal, not that I did not know
of any river navigation's of which there are quite a few.

Ok.

The Lea( Shouldn't it be Lee which differentiates it from the other?)

Yeah, I thought I read how they were spelled differently for such a
reason but again, have since forgotten. ;-(

checks No wonder this mild dyslexic gets confused: ;-)

https://en.wikipedia.org/wiki/River_Lea#Etymology

is quite wide and I don't think such a construction would suit.

Ok. I thought I remembered seeing one but it might have just been a
picture somewhere.

Some commentators mention that the Stratford was unique in having them
but there is one about 15 miles away from me as I type and I'm sitting
in North Devon.

There is often 'the exception that breaks the rule'. ;-)

picture 25 on this gallery
http://www.bude-canal-trust.co.uk/main-gallery/
That has been strengthened in the 130 or so years since a the canal
closed

I can't see what was the gap with my eyes from that pic. ;-(

but photo 9 in the same set shows recovered sections of
metalwork from another bridge nearby that no longer exists.

That's a neat use of it to keep the design in peoples minds (a gap in
the 'table' might have kept that clearer though). ;-)

Cheers, T i m

In message , T i m
writes
On Tue, 29 Aug 2017 01:04:57 +0100, wrote:

On Mon, 28 Aug 2017 23:40:30 +0100, T i m wrote:

Didn't some bridges across rivers and canals gave a gap in the middle
Yes , some canals. Don't know of a river navigation .

What about the River Lea (Navigation) (as opposed to the one that runs
parallel to it that isn't navigable)?

What I meant was that I did not know of any fixed split bridge on a
River Navigation as opposed to a narrow canal, not that I did not know
of any river navigation's of which there are quite a few.

Ok.

The Lea( Shouldn't it be Lee which differentiates it from the other?)

Yeah, I thought I read how they were spelled differently for such a
reason but again, have since forgotten. ;-(

checks No wonder this mild dyslexic gets confused: ;-)

https://en.wikipedia.org/wiki/River_Lea#Etymology

It has been Lea here all my life but there was a pre-war cast iron
notice board threatening poachers with dire consequences if they dared
to fish the *Lee Conservancy*:-)
--
Tim Lamb

On Tue, 29 Aug 2017 10:29:00 +0100, Tim Lamb
wrote:

snip

https://en.wikipedia.org/wiki/River_Lea#Etymology

It has been Lea here all my life but there was a pre-war cast iron
notice board threatening poachers with dire consequences if they dared
to fish the *Lee Conservancy*:-)

I remember that term but wasn't sure where it was from (era / usage).

Cheers, T i m

On Mon, 28 Aug 2017 14:05:37 +0100, wrote:

There are often complaints from the horsey community that this is so
and they frequently wail that the Towpath was built for horses.
Ignoring the fact that the horses were not being ridden and proceeded


A barrister I used to work for insisted that up till the 1947 town and
country planning act bridle ways were just roads along which horses
had to be led by the bridle.

Also as most navigable rivers were established by act of parliament
the rights granted for their towpaths were strictly for the conveyance
of goods, as time went by and powered boats took over the towpaths
fell into disuse and the original landowners took them back in hand,
often developing them such that a continuous pathway no longer exists
at all. OTOH the towpaths on canals were established as the canal was
built on land acquired through an act of parliament and as the canal
companies passed away and the canals were acquired by the current
trusts so the towpaths became permitted footpaths and a great resource
they are too.

G.Harman

A famous name on the bit of canal I frequent (on foot, bike and
"Isabella" when she over winters).

AJH

On Monday, 28 August 2017 00:50:17 UTC+1, T i m wrote:
On Sun, 27 Aug 2017 15:53:15 -0700 (PDT), tabbypurr wrote:

Lead acids can set fire to things with their huge output current,

As can Li, but not generally on their own simply because you have
over-discharged them.

Poor connections.

Sue, but I'll be wiring it all up so there won't be any of those. ;-)

I hope you're kidding there

But they don't need fire to kill you, a battery producing boiling sulphuric acid fumes is no laugh.

Whilst I'm not saying there are *no* risks, I'm saying there are much
fewer risks than say with Li.

of course

DAMHIKT.

I don't think I need to weg.

I see no sense in your plans, the downsides surely outweigh the upsides.

Such as? I thought I made the pros and cons pretty clear and were
no-brainers for our needs?

Cheers, T i m

Each to their own.


NT

On Monday, 28 August 2017 13:34:24 UTC+1, T i m wrote:

charging RC cars and camping etc) and whilst my observations are just
a sample of one, I don't know personally of anyone who has had a LA
battery do them any harm

I had one try, but once I couldn't breathe I got out very fast.


NT

On 31/08/17 13:02, wrote:
On Monday, 28 August 2017 13:34:24 UTC+1, T i m wrote:

charging RC cars and camping etc) and whilst my observations are just
a sample of one, I don't know personally of anyone who has had a LA
battery do them any harm

I had one try, but once I couldn't breathe I got out very fast.


NT

I was narrowly missed by the shrapnel.

Fork lift with failing battery left on charge overnight, chargehand
(sic) takes off battery clip without shutting down charger, spark,
massive hydrogen explosion and the battery splits into several large
heavy pieces.
And a lot of plastic shards.
And sulphuric acid
We washed down the fizzing floor and the chargehand, and scraped the
old battry bits into a plastic bag, and bought a new battery.


Lithium polymer may catch fire, but they don't explode...


--
"The great thing about Glasgow is that if there's a nuclear attack it'll
look exactly the same afterwards."

Billy Connolly

On Thu, 31 Aug 2017 04:57:30 -0700 (PDT), wrote:

On Monday, 28 August 2017 00:50:17 UTC+1, T i m wrote:
On Sun, 27 Aug 2017 15:53:15 -0700 (PDT), tabbypurr wrote:

Lead acids can set fire to things with their huge output current,

As can Li, but not generally on their own simply because you have
over-discharged them.

Poor connections.

Sue, but I'll be wiring it all up so there won't be any of those. ;-)

I hope you're kidding there

Assuming you are talking about the only bit I don't have control of,
eg, inside the battery itself then yes, you are right.

Outside of the battery, nope, there will be no poor connections
because I will be making them.

snip

I see no sense in your plans, the downsides surely outweigh the upsides.

Such as? I thought I made the pros and cons pretty clear and were
no-brainers for our needs?


Each to their own.

Well, a part of it is that of course but the underlying reason is the
poor fit of anything other than Lead Acid for me and this roll.

Cons for anything other than Lead Acid (and ignoring Nicad, NiMh or
anything exotic here), eg, mainly LiPo / Li-Ion.

1) Highly intermittent use (where LA can be left on trickle charge
24/7).

2) A higher chance of spontaneous combustion if overcharged or
damaged.

3) Massive investment in the batteries (and Li technology is still
changing fast).

4) Massive investment in the charging equipment (because) ...

5) Batteries need to be stored at a storage charge level requiring
fast top-up when required at short notice.

6) Batteries need to be discharged to a storage charge level if
charged and not used.

7) Batteries cannot be left unsupervised on charge.

8) Batteries ideally need to be charged, stored and transported in a
fireproof enclosure.


On the pro side for Li-xx, they would be lighter (for the same kWh).
;-)

Cheers, T i m

On Thursday, 31 August 2017 15:05:30 UTC+1, T i m wrote:
On Thu, 31 Aug 2017 04:57:30 -0700 (PDT), tabbypurr wrote:
On Monday, 28 August 2017 00:50:17 UTC+1, T i m wrote:
On Sun, 27 Aug 2017 15:53:15 -0700 (PDT), tabbypurr wrote:

Lead acids can set fire to things with their huge output current,

As can Li, but not generally on their own simply because you have
over-discharged them.

Poor connections.

Sue, but I'll be wiring it all up so there won't be any of those. ;-)

I hope you're kidding there

Assuming you are talking about the only bit I don't have control of,
eg, inside the battery itself then yes, you are right.

Outside of the battery, nope, there will be no poor connections
because I will be making them.

So you weren't joking.

On Thu, 31 Aug 2017 13:11:58 +0100, The Natural Philosopher
wrote:

snip

I was narrowly missed by the shrapnel.

Are you sure none was left stuck in your head? ;-)

Fork lift with failing battery left on charge overnight,

Poor maintenance.

chargehand
(sic) takes off battery clip without shutting down charger,

Poor usage / training.

spark,
massive hydrogen explosion and the battery splits into several large
heavy pieces.

But no fire?

And a lot of plastic shards.
And sulphuric acid
We washed down the fizzing floor and the chargehand, and scraped the
old battry bits into a plastic bag, and bought a new battery.

But you didn't have to call the fire brigade to try to extinguish the
burning building?


Lithium polymer may catch fire,

And do: https://www.youtube.com/watch?v=fF9fhlr9S5s
https://www.youtube.com/watch?v=CnNId0mDnBo

but they don't explode...

But the container they are being stored in then could?

Li-Ion can explode though, and gel LA rarely do, nor leak acid if
damaged.

https://www.youtube.com/watch?v=ZTzEHsJVZhA

(worth watching at the end just for the slo-mo). ;-)

Cheers, T i m

On Thu, 31 Aug 2017 07:21:04 -0700 (PDT), wrote:

On Thursday, 31 August 2017 15:05:30 UTC+1, T i m wrote:
On Thu, 31 Aug 2017 04:57:30 -0700 (PDT), tabbypurr wrote:
On Monday, 28 August 2017 00:50:17 UTC+1, T i m wrote:
On Sun, 27 Aug 2017 15:53:15 -0700 (PDT), tabbypurr wrote:

Lead acids can set fire to things with their huge output current,

As can Li, but not generally on their own simply because you have
over-discharged them.

Poor connections.

Sue, but I'll be wiring it all up so there won't be any of those. ;-)

I hope you're kidding there

Assuming you are talking about the only bit I don't have control of,
eg, inside the battery itself then yes, you are right.

Outside of the battery, nope, there will be no poor connections
because I will be making them.

So you weren't joking.

Correct. Why should I have been (and please don't judge others by your
own (in)abilities). ;-)

Cheers, T i m