Dry stack diesel - 4.236 Perkins diesel

As some of you know I have posted that my wife and I are building a 34' steel hull Union Jack from plans from Glen-L and recently took a trip to New Brunswick, Canada, I had a chance to speak to a lobster fisherman who told me he installed a regular 4.236 Perkins diesel and the only thing he did to marinize the boat was to put keel coolers on the hull and an 8' (4" dia.) pipe with a truck muffler on from the exhaust manifold running up the side of the pilot house. I also ask him about exhaust manifold cooling (i.e. water cooled) and he replied there was none and it was not a Perkins marine engine. I ask is this possible? Any help would be appreciated because the Union Jack is apparently built around a dry stack system

Iceman46

 

Definitely possible. Just not quiet. You'll sound like a commercial fishing vessel.

The only reason exhaust is 'marinized" is to cool down the exhaust system and quiet the roar.

If you route the pipe right up, just like he did, on a steel boat, you're good to go. It's not necessary to marinize exhaust, just a nice plus.

You can use any engine you want and keel cool it.

Perkins, Yanmar tractor, Isuzu, Mercedes straight 5, Pugeot, whatever.

 

Boils down how to cool the engine room. If there's big blowers and a lot of space around the engine then it's no worries without water jacketed exhaust manifold or isolation on the dry stack..

 

With a taller stack you can help to cool the engine room using the waste heat from the exhaust to 'power' a chimney.

The exhaust pipe runs in the center of a much wider pipe or stack (open to the engine room at the base and vents at the top) - the heat it generates warms the air in the space around the exhaust and as this heats up and rises it both cools the exhaust and draws air up from the engine room. If there's a muffler section the stack needs to have a good clearance around that muffler so as not to restrict air flow.

insulation can be incorporated and this is both a safety and comfort feature - actually being able to touch the exhaust pipes can result in serious burns, but the insulation also reduces the noise too.

 

Thanks for the info AndySGray

 

Thanks for info TeddyDiver

 

Thanks for the info snowbirder

 

If you wish a cooler engine room the std water cooled exhaust manifold can be plumbed into the keel cooler , with the rest of the cooling water.

It requires a bigger keel cooling unit , and as with all keel cooling , a bypass thermostat to make sure the water returning from the cooler is not too cold.

Usually about a 20-30deg drop (as in a car or truck) works best.

The stock thermostat will not help the shock cooling from too cold return water.

The system will be designed to cool at max load , 85F water with mild surface fouling , as few ever see this extreme , over-cooling is the result.

In a steel vessel there are a number of ways the cooler can be part of the hull of the vessel, no drag at all.

A shallow box is welded inside and a labyrinth created the coolant passes thru .

Gerr shoes hoe in one of his books,

The use of a truck exhaust can be fairly quiet , and cheap, BUT if its a Yacht , look up Hospital Critical silencers .

These are mounted on the top of the vessel and really quiet.

Not cheap, and not light , but sometimes can be found used.

IF the exhaust pipe is to be internal, be sure to install wet lockers to dry clothes next to the insulated exhaust passage.

Some folks have been known to simply stick the 4 in exhaust inside a SS fireplace insulated flue pipe .

Cuts the heat and noise down.

To my mind for a cruiser that wants almost zero maint , dry stack,keel cooled is the best solution.

Exhaust Silencers - Maxim Silencers
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GT Exhaust - Harmony H1-6 Super Critical Grade Silencer
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Harmony™ H1-6 Super Critical Grade 2" Packing (34 to 40 dB(A)) ... its Harmony™ H1-6 Super Critical/Hospital Grade Silencers with improved heat capabilities.
Engine Exhaust Silencers – Universal
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Universal AET's exhaust silencers provide the best performance for all engine ... The single inlet models are available in residential, critical and hospital ...
Exhaust & Blower Silencers - Thermal Transfer Systems, Inc.
www.thermaltransfersystems.com/Exhaust...Silencers/exhaust_blower_sil...
Exhaust & Blower Silencers are available in industrial, residential, critical, and hospital attenuation grades. %u2013 we also offer a complete line of accessories.

 

Thanks for the wealth of info Fast Fred

 

The fireplace insulated pipe also has the advantage of leading off exhaust fumes , should the exhaust rust thru in a few decades.

If the hospital silencer is not used , you will also need a metal pail to place over the top of the stack when not operating.

While a wet exhaust manifold may be expensive , as only coolant with antifreez is running thru , it least its a one time purchase , unlike sea water cooled.

The Nature of boats by Dave Gerr

and the 1st release of Passagemaking by Beede will be of interest.

The second edition was a reprint after a re write by the sales dept of boat sellers.