Dry to Wet exhaust

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Jim and Becky - 23 Dec 2005 02:23 GMT

I'm considering the purchase of a 32 foot lobster boat. It has a Cat
straight 6 diesel with a dry exhaust.
Does anyone have experience in changing this set up over to a through
transom wet exhaust?
I'm concerned about the height of the pipe relative to the waterline and
possible intrusion into the engine.

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Lew Hodgett - 23 Dec 2005 02:50 GMT

> I'm considering the purchase of a 32 foot lobster boat. It has a Cat
> straight 6 diesel with a dry exhaust.
> Does anyone have experience in changing this set up over to a through
> transom wet exhaust?
> I'm concerned about the height of the pipe relative to the waterline and
> possible intrusion into the engine.

Heck of a troll.

Lew

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Jim and Becky - 23 Dec 2005 23:13 GMT

I admit I'm new to diesels and won't wilt at surprises.
What are you talking about?

> > I'm considering the purchase of a 32 foot lobster boat. It has a Cat
> > straight 6 diesel with a dry exhaust.
[quoted text clipped - 6 lines]
>
> Lew

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Lew Hodgett - 24 Dec 2005 19:33 GMT

> I admit I'm new to diesels and won't wilt at surprises.
> What are you talking about?

As Dave W has already responded, a dry stack exhaust is the best you can
have.

Boat probably is also equipped with a keel cooler.

If it is, another real plus.

Lew

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Dave W - 24 Dec 2005 14:31 GMT

This can certainly be done, but why? Dry exhaust has some real advantages,
especially in winter operation; exhaust system cannot freeze. Additionally,
you eliminate the water injection elbow which is an achillies heel of
diesels. With a suitable muffler the sound of a dry exhaust is sweet. Just
stay away from the hot pipe!
To replace, you will need a water lift muffler, injection elbow and
associated piping, rubber hose, vacuum breaker and through transom fittings.
Have a look at the waterlift muffler manufacturers pages to learn about
height requirements. The height of the wet elbow above the muffler and the
height of the wet loop above the waterline are critical requirements. These
are not easily met in lots of lobster boats because of the need for a level
working deck.

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Jim and Becky - 25 Dec 2005 04:02 GMT

Thanks for your help.
I'm turning it into a picnic boat in New England so no off season use.
Moving it to wet exhuast as the women in spaghetti strap cocktail dresses
don't want cinders in their Cosmopolitans as they lounge in the aft deck.

I've seen some water lift mufflers at www.marineexhaust.com. , but this is a
420 hp engine.
Can you give a brief explanation of Injection Elbow, Vacum Breaker, and wet
loop?

This is alow slung engine.
Mounted 3 cylinders in the cabin, 3 in the wheelhouse.

> This can certainly be done, but why? Dry exhaust has some real advantages,
> especially in winter operation; exhaust system cannot freeze. Additionally,
[quoted text clipped - 14 lines]
> > I'm concerned about the height of the pipe relative to the waterline and
> > possible intrusion into the engine.

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derbyrm - 25 Dec 2005 12:14 GMT

Get a copy of "Boatowner's Mechanical & Electrical Manual: How to Maintain,
Repair, and Improve Your Boat's Essential Systems" by Nigel Calder. He does
a great job of explaining with illustrations and alternatives; e.g. instead
of a vacuum breaker he likes a small tubing venting into the cockpit. If it
isn't wet, shut off the engine.

Roger
derbyrm@NOSPAMinsightbbNOSPAM.com
http://home.insightbb.com/~derbyrm

> I've seen some water lift mufflers at www.marineexhaust.com. , but this is
> a 420 hp engine.
> Can you give a brief explanation of Injection Elbow, Vacum Breaker, and
> wet
> loop?

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Boat Forum / Building / December 2005

Dry to Wet exhaust