Wet Exhaust Conversion

[jimthom]

I have a keel cooler and a dry exhaust. I want to change over to a wet exhaust because of the noise. I've got everything sorted except suppling water to the lift muffler. Do you have any solutions? My boat is 11m monohull with an Isuzu 33HP diesel.
Thank you, Jimthom

[Uncle Bob]

Originally Posted by jimthom

I have a keel cooler and a dry exhaust. I want to change over to a wet exhaust because of the noise. I've got everything sorted except suppling water to the lift muffler. Do you have any solutions? My boat is 11m monohull with an Isuzu 33HP diesel.
Thank you, Jimthom

I guess the options are
* Add a saltwater pump to supply the water to the waterlift muffler
* Retain the existing arrangement and improve the muffler / mufflers to
quieten the beast

Should you go with the water pump I would add a belt driven pump to the engine and plumb it to the muffler direct.

[Lepke]

There are 12v pumps available that would supply enough water to keep the exhaust cool. Some people use magnet drive pumps. Remember, you need to flush a salt water system occasionally to remove the marine growth. Use a loop in the exhaust so you don't flood your engine.

[mvweebles]

This really should be belt drive off the engine to assure the pump only operates when the engine operates. Otherwise you are at risk of flooding the exhaust manifold. Pump itself can be mounted to a stringer.

[tkeithlu]

Thought: Most diesel engines, at least the ones used for stationary gensets, come with three grades of muffler, ordinary, residential, and hospital. Before you do major surgery on your boat, consider moving to a better muffler. Also consider how much of the noise you are finding unpleasant comes from the engine rather than the exhaust. You may need a sound resistant box for your engine.

Think of it this way. Cars have dry exhausts. Cars have diesel engines in the 100+ HP class. Cars have engineers who have dampened noisy harmonically vibrating fuel tanks and body work. Cars are not loud.

[jimthom]

Thanks everyone for their input. My Isuzu 3LD1 came with poor documentation, but I did discover that it came with a PTO hidden behind a cover plate which will make the installation straight forward, once I purchase a $500 raw water pump. Still, you can't put a price on a little peace and quiet.

[Compass790]

Originally Posted by jimthom

Thanks everyone for their input. My Isuzu 3LD1 came with poor documentation, but I did discover that it came with a PTO hidden behind a cover plate which will make the installation straight forward, once I purchase a $500 raw water pump. Still, you can't put a price on a little peace and quiet.

Please post back how you rate the improvement after you have done the install.
Wish the stinking commercial fish boats that sometimes anchor near us would invest in hospital grade mufflers for their generators.