Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

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Old March 22nd 20, 07:05 PM posted to rec.crafts.metalworking
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Default Diesel 500HP marine - straight-6 vs V12

Hello all

You are a group with a lot of technical interests and knowledge.

Boats - for a vessel with a single screw and about 500HP, or a
twin-screw vessel with about 1000HP (500HP each engine and gearbox
drive)...

Some have a/two straight-6cylinder engine(s) like the Cummins K19(M?)

Some have a/two Caterpillar 3412 V12 engine(s)

Why?

The straight-6 would be - cheaper? simpler?
The V12 would be - ... ?

Thanks in advance is you can help take this curiousity to its
end-point.

Regards,
Rich S

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Old March 23rd 20, 03:57 AM posted to rec.crafts.metalworking
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Default Diesel 500HP marine - straight-6 vs V12

On Sun, 22 Mar 2020 19:05:58 +0000, Richard Smith
wrote:

Hello all

You are a group with a lot of technical interests and knowledge.

Boats - for a vessel with a single screw and about 500HP, or a
twin-screw vessel with about 1000HP (500HP each engine and gearbox
drive)...

Some have a/two straight-6cylinder engine(s) like the Cummins K19(M?)

Some have a/two Caterpillar 3412 V12 engine(s)

Why?

The straight-6 would be - cheaper? simpler?
The V12 would be - ... ?

Thanks in advance is you can help take this curiousity to its
end-point.

Regards,
Rich S


You want to be many miles out at sea and have your only engine pack
up?

Thats one of the main reasons to have 2 or more engines.
Secondly..each engine turns its own prop. 2 props push mass far far
better than one..so it can be more efficient and much faster
underweigh.

The advantages of 2 props that are independantly reversable for boat
handling is also a very BIG advantage. (along with an engine for a bow
thruster)

Gunner
__

"Journalists are extremely rare and shouldnít be harmed, but propagandists are everywhere and should be hunted for sport"

Yeah..with no bag limit.




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Old March 23rd 20, 06:43 AM posted to rec.crafts.metalworking
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Default Diesel 500HP marine - straight-6 vs V12

Gunner Asch writes:

On Sun, 22 Mar 2020 19:05:58 +0000, Richard Smith
wrote:

Hello all

You are a group with a lot of technical interests and knowledge.

Boats - for a vessel with a single screw and about 500HP, or a
twin-screw vessel with about 1000HP (500HP each engine and gearbox
drive)...

Some have a/two straight-6cylinder engine(s) like the Cummins K19(M?)

Some have a/two Caterpillar 3412 V12 engine(s)

Why?

The straight-6 would be - cheaper? simpler?
The V12 would be - ... ?

Thanks in advance is you can help take this curiousity to its
end-point.

Regards,
Rich S


You want to be many miles out at sea and have your only engine pack
up?

Thats one of the main reasons to have 2 or more engines.
Secondly..each engine turns its own prop. 2 props push mass far far
better than one..so it can be more efficient and much faster
underweigh.

The advantages of 2 props that are independantly reversable for boat
handling is also a very BIG advantage. (along with an engine for a bow
thruster)

Gunner


That's about having two engines, regardless of what type.

For sure, the twin-screw boats are in a much higher class and
capability. I as a welder with minimal boating skills can see that.
The way they can rotate barges they are tethered to - very desirable.
One engine forward and one engine astern.
Our area is very tidal, with two nearly identical tides per day
(12hr50min apart) (the Pacific has, in the main, just one tide per
day??).
So the ability to manoevre in big tidal ebbs and flows is especially
needed. Plus - propellers do get damaged in estuary work, and having
two engines it leaves you with one to get finished and get to a yard.

That I have observed - both manouvrability and surviving damage.

Then there is the question - what causes the choice between a
straight-6 and a V12?
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Old March 23rd 20, 11:35 AM posted to rec.crafts.metalworking
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Default Diesel 500HP marine - straight-6 vs V12

On Sun, 22 Mar 2020 19:05:58 +0000, Richard Smith
wrote:

Hello all

You are a group with a lot of technical interests and knowledge.

Boats - for a vessel with a single screw and about 500HP, or a
twin-screw vessel with about 1000HP (500HP each engine and gearbox
drive)...

Some have a/two straight-6cylinder engine(s) like the Cummins K19(M?)

Some have a/two Caterpillar 3412 V12 engine(s)

Why?

The straight-6 would be - cheaper? simpler?
The V12 would be - ... ?

Thanks in advance is you can help take this curiousity to its
end-point.

Regards,
Rich S


I'm no naval architect, and only have outboards. Nothing near that
size. I would guess the V-12's advantage would be more compact size
for boat design, as well as possibly higher rpm, different vibration
qualities for easier soundproofing in high end applications. The
sixes would probably be easier to maintain, not just because of less
parts, but because the package shape would lend itself to better
access in the engine room.

Just thinking on the keyboard here.

Pete Keillor
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Old March 23rd 20, 01:05 PM posted to rec.crafts.metalworking
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Default Diesel 500HP marine - straight-6 vs V12

Pete Keillor writes:

On Sun, 22 Mar 2020 19:05:58 +0000, Richard Smith
wrote:

Hello all

You are a group with a lot of technical interests and knowledge.

Boats - for a vessel with a single screw and about 500HP, or a
twin-screw vessel with about 1000HP (500HP each engine and gearbox
drive)...

Some have a/two straight-6cylinder engine(s) like the Cummins K19(M?)

Some have a/two Caterpillar 3412 V12 engine(s)

Why?

The straight-6 would be - cheaper? simpler?
The V12 would be - ... ?

Thanks in advance is you can help take this curiousity to its
end-point.

Regards,
Rich S


I'm no naval architect, and only have outboards. Nothing near that
size. I would guess the V-12's advantage would be more compact size
for boat design, as well as possibly higher rpm, different vibration
qualities for easier soundproofing in high end applications. The
sixes would probably be easier to maintain, not just because of less
parts, but because the package shape would lend itself to better
access in the engine room.

Just thinking on the keyboard here.

Pete Keillor


Let's see if anyone with commercial marine experience responds.
Your surmises are the sort of thing I would wonder.
Regards, Rich Smith


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Old March 23rd 20, 02:02 PM posted to rec.crafts.metalworking
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Default Diesel 500HP marine - straight-6 vs V12

Peter - when surmising, you'd only have to miss / be oblivious to just
one significant factor and the entire balance and therefore optimum
solution is missed.
Reason I asked the open-ended question.
Regards,
Rich
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Old March 24th 20, 12:29 AM posted to rec.crafts.metalworking
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Default Diesel 500HP marine - straight-6 vs V12

On 23/3/20 5:43 pm, Richard Smith wrote:
(the Pacific has, in the main, just one tide per
day??).


No. Everywhere on earth, there are (almost) two tides per day, because
the high tides circulate (roughly following the moon) on *opposite*
sides of the globe.

It's like two dancers spinning around each other - both are flung
outwards away from the centre.

On average, the moon contributes about 1 metre of tidal flow, and the
sun about 0.5 metres. When these line up, you get 1.5m, and when they're
at right angles, you get 0.5m.

Up to here, all this can be calculated from the gravitational equation,
with knowledge of the orbits, masses and distances of the earth, moon
and sun.

Places with very high tides are like the slosh in the corner of a square
bucket - they're at "corners" of the oceans.

Clifford Heath.
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Old March 24th 20, 11:08 AM posted to rec.crafts.metalworking
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Default Diesel 500HP marine - straight-6 vs V12

"Clifford Heath" wrote in message
...
On 23/3/20 5:43 pm, Richard Smith wrote:
(the Pacific has, in the main, just one tide per
day??).


No. Everywhere on earth, there are (almost) two tides per day,
because the high tides circulate (roughly following the moon) on
*opposite* sides of the globe.

It's like two dancers spinning around each other - both are flung
outwards away from the centre.

On average, the moon contributes about 1 metre of tidal flow, and
the sun about 0.5 metres. When these line up, you get 1.5m, and when
they're at right angles, you get 0.5m.

Up to here, all this can be calculated from the gravitational
equation, with knowledge of the orbits, masses and distances of the
earth, moon and sun.

Places with very high tides are like the slosh in the corner of a
square bucket - they're at "corners" of the oceans.

Clifford Heath.


You are both right, depending on where you look.
https://www.britannica.com/place/Pacific-Ocean/Tides


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Old March 24th 20, 06:05 PM posted to rec.crafts.metalworking
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Default Diesel 500HP marine - straight-6 vs V12

Hi Jim, all

I've simply heard about this big difference of our Atlantic tides with
the Pacific. Cannot make informed comment.

Here in South Devon - the "English Channel" side of Devon on the West
Country peninsula - tide ranges are something like 4.3m on "spring"
tides and 1.7m on "neaps (I easily found 4.5m range "spring" and 1.5m
range "neap").
Working on marine tubular piles with a 4+m tide range has its
interesting aspects ;-)


On the original question of engines:
Wikipedia proved very useful
https://en.wikipedia.org/wiki/Straight-six_engine
https://en.wikipedia.org/wiki/V12_engine
Other Web searches seeking to know the comparative advantages of
I6-vs-V12 produced some more comment, like optimum bore/stroke ratio
being different between the two types, etc.
I don't have the ability to even collate the impressions gained and
summarise.

Just one comment - the inherent excellent balance characteristics of a
six-throw crankshaft means the V12 can have a 60degree angle - not
90degree as needed for most other "V"'s - so the engine can be notably
compact - it's narrower for a "V" than it otherwise would be -
advantageous for a boat where likely can accomodate length no penalty
but width is strongly undesirable.

I do note that the "500HP" (commercial) Caterpillar V12 is offered in
a leisure-craft-only variant giving 1300HP - which surely a 500HP
straight-6 cannot morph to - I assume it sticks at 500HP and that's
it?

Is there the case that Caterpillar saw a vast market for the V12,
across many in-house earthmoving eqt. plus "external" industrial and
marine applications, so took a deep breath and invested the cash
building a high-volume production-line, much flattening the cost
differential between their V12 and and anyone else's I6???


Best wishes,
Rich S.
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Old March 24th 20, 07:23 PM posted to rec.crafts.metalworking
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Default Diesel 500HP marine - straight-6 vs V12

On 24/03/2020 18:05, Richard Smith wrote:
Hi Jim, all

I've simply heard about this big difference of our Atlantic tides with
the Pacific. Cannot make informed comment.

Here in South Devon - the "English Channel" side of Devon on the West
Country peninsula - tide ranges are something like 4.3m on "spring"
tides and 1.7m on "neaps (I easily found 4.5m range "spring" and 1.5m
range "neap").
Working on marine tubular piles with a 4+m tide range has its
interesting aspects ;-)


On the original question of engines:
Wikipedia proved very useful
https://en.wikipedia.org/wiki/Straight-six_engine
https://en.wikipedia.org/wiki/V12_engine
Other Web searches seeking to know the comparative advantages of
I6-vs-V12 produced some more comment, like optimum bore/stroke ratio
being different between the two types, etc.
I don't have the ability to even collate the impressions gained and
summarise.

Just one comment - the inherent excellent balance characteristics of a
six-throw crankshaft means the V12 can have a 60degree angle - not
90degree as needed for most other "V"'s - so the engine can be notably
compact - it's narrower for a "V" than it otherwise would be -
advantageous for a boat where likely can accomodate length no penalty
but width is strongly undesirable.

I do note that the "500HP" (commercial) Caterpillar V12 is offered in
a leisure-craft-only variant giving 1300HP - which surely a 500HP
straight-6 cannot morph to - I assume it sticks at 500HP and that's
it?

Is there the case that Caterpillar saw a vast market for the V12,
across many in-house earthmoving eqt. plus "external" industrial and
marine applications, so took a deep breath and invested the cash
building a high-volume production-line, much flattening the cost
differential between their V12 and and anyone else's I6???


Best wishes,
Rich S.


Richard,

¬*¬*¬* Have a look at the Cox marine diesel outboard
https://www.coxmarine.com/ as it's a 60 degree V8 for compactness which
means it uses a flying web crank design for even firing. I know a bit
about it as a friend was involved in some of the design.



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