VOLVO Inboard exhaust

brailediver

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Mar 18, 2005
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29
I have a 25' Kencraft with a TAMD41 diesel. I am converting this boat to use as a dive boat & would like to get the exhaust overhead instead of through the transom. Anyone here have any info on this procedure? I know shrimp boats do it.<br /> Thanks,<br /> Gene
 

f_inscreenname

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Aug 23, 2001
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2,591
Re: VOLVO Inboard exhaust

A lot of lobster men in New England use a dry exhaust stack (all it is, is a straight pipe with a muffler in the middle). The only issue is the heat that comes off it. In N.E. even the summer mornings are cold so most don't mind it but on a dive boat it may be a issue (safety wise if you are for hire. Then there is the heat especially in the summer. <br />What is the reason for wanting to do this? I can not see where the exhaust is would be a issue on a dive boat. The motor should be off when diving and the exhaust ports should not ever be hot.
 

markvictor

Seaman
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Dec 14, 2005
Messages
62
Re: VOLVO Inboard exhaust

First, you have to reroute your raw water to discharge overboard, as it now discharges via your exhaust elbow... Ideally you would have a new manifold installed which is designed for dry stacking, either a manufactured one, or have a custom manifold fabricated, if your manifold is raw water cooled or you could build a blanking plate fot the outlet to block off the water passages, and route your raw water in one end and out the other on the bottom of the manifold, and then overboard. (You will have to determine if that is possible, I'm at home and can't look at one right now...). When you build your stack, make sure you leave a water trap and valve at the base to drain off accumulated water from rain, etc. the entire ehaust will have to be insulated to prevent a fire...What is your reasoning for dry-stacking anyway? If it's for a compressor, you are better off using a remote air intake and keep IT high and upwind..carbon monoxide will collect in low semi enclosed areas, such as your aft deck...<br />A co indicator on your final filter is cheap insurance against bad air...I spent 8 years diving for the USN, this is the configuration of choice...exhaust low, compressor intake high upwind...If you're doimg it for ingress/egress from the swimstep, I would just reroute the exhaust out the side, or underwater...<br />regards,<br />markvictor<br />PS:Braille has 2 l's...lol
 

Don S

Honorary Moderator Emeritus
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Aug 31, 2004
Messages
62,321
Re: VOLVO Inboard exhaust

No need to worry about the exhaust manifold, it's cooled with Antifreeze on a 41. All you have to do is get a dry elbow and plumb your dry stack to where evdr you want it. Volvo has specs for them, regarding number of angles and max bend. I'll see if I can't find it and post it for you.
 

brailediver

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Joined
Mar 18, 2005
Messages
29
Re: VOLVO Inboard exhaust

Some divers complain about fumes. It is only a problem when we are idling around looking for our target. The fumes sometimes seem to float up over the transom. I have room to build some kind of shield around the stack to isolate it from fire or accidental burning of a customer. Thanks for the help!<br /> Gene
 

brailediver

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Mar 18, 2005
Messages
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Re: VOLVO Inboard exhaust

Braillediver, in my opinion, would be used to describe a blind diver. I am not blind, but, I dive in low to zero visibility.<br />Gene
 

markvictor

Seaman
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Dec 14, 2005
Messages
62
Re: VOLVO Inboard exhaust

Hey bd,<br />You mean like when you're three decks down inside a salvage job and your light fails?<br />Sometimes you don't want to see what's around when diving...searching for remains in plane fuselages comes to mind..you get over the "feel"...but the visuals don't go away for some time...<br />regards,<br /> markv
 

Don S

Honorary Moderator Emeritus
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Messages
62,321
Re: VOLVO Inboard exhaust

It must have been the little baby diesel that had all the exhaust restrictions on it. The 41 is a basic setup. Just keep the back pressure of the system between 2.9 and 4.4 psi. To high will damage the engine, too low probably can't happen unless you have an extreamly short exhaust and no muffler. And I doubt you want that.<br /><br />Here is about all that's in the installation manual regarding the dry exhaust. There is a section that explains how to check the exhaust back pressure if you wanted to check it. If you want the install manual, you can order it from your local Volvo dealer. It's part number 7741513.<br /><br />
Dry%20Exhaust%2041.png
 
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