Smoke in engine compartment

[Mike Thompson]

I have an escape of exhaust fumes. Light colored and not very thick but the cabin
needs a lot of ventilation after some motoring. Also contents of the cockpit lockers
get filthy with oily grime.

I can't see where it is escaping. After starting the engine it appears to be in the air
everywhere without a local concentration.

Any ideas on how to locate the source?

Mike

[Jim Walsh]

Start at the exhaust riser and work your way to the terminal end of the exhaust at the transom. Clearly at some point a crack, hole, split, or loose connection will reveal itself.
If you wait until after dark you can start the engine and use a penlight (so you can direct a pinpoint beam) to see where the smoke seems to be eminating from. The light bounces off the smoke. Then you can focus your physical search there.
We all know you need plenty of ventilation and should not do this alone. Carbon monoxide kills.

[M. R. Bober]

Find the source and fix it immediately! If the leak is diesel exhaust from aft of the mixing elbow, you will be filling the boat with carbon monoxide and water. Asphyxiation or sinking are two poor outcomes. If the leak is exhaust from forward of the elbow, asphyxiation without sinking is possible. In either case, the sooty smoke makes a terrible mess which is difficult to clean.

If the smoke is from an electrical source, fire is a real concern.

Mitchell Bober
Sunny Lancaster (Where there is smoke, there may be fire.) VA

[tjr818]

And if that is not bad enough, as mention in another recent post, if all of the smoke escapes your electronics will stop working

[Mike Thompson]

Thanks for your advice. Will do next time I go to Maine.
Mike

[Tom Keevil]

A rusted out exhaust riser is a prime suspect. Unwrap the insulation and take a look.

[M. R. Bober]

A rusted out exhaust riser is a prime suspect. Unwrap the insulation and take a look.

Excellent advice. On a CDSOA Chesapeake Fleet cruise two or three years ago, we had two boats whose exhaust risers failed. Mine was one. I was single handing and not aware of the smoke for too long. The scrub down/clean up was/is miserable.

As I frequently single hand, I installed a smoke detector in the cabin.

Mitchell Bober
Sunny Lancaster, (Where we know that smoking is no good for you.) VA

[Mike Thompson]

Interestingly enough the smoke problem remains there was a much more serious problem.

I found water pouring out of the exhaust! The cause was that there was no mechanical
connection between inverted 'U' at the top of the exhaust and the 'descender' pipe which also
had the salt water mixing junction. The two pipes had been abutted one against the other
and then wrapped together with heat resistant cloth and tightly bound with wire.
This (shoddy) state of affairs had lasted for a least 16 years!

I slathered the junction with Marine Tex Gray and then used a Home Depot pipe junction
with hose clamps. This has stopped the spraying of water for now.

Mike

[M. R. Bober]

Interestingly enough the smoke problem remains there was a much more serious problem.

I found water pouring out of the exhaust! The cause was that there was no mechanical
connection between inverted 'U' at the top of the exhaust and the 'descender' pipe which also
had the salt water mixing junction. The two pipes had been abutted one against the other
and then wrapped together with heat resistant cloth and tightly bound with wire.
This (shoddy) state of affairs had lasted for a least 16 years!

I slathered the junction with Marine Tex Gray and then used a Home Depot pipe junction
with hose clamps. This has stopped the spraying of water for now.

Mike

A weldment is called for at the junction. Marine Tex is--IMO--strictly a temporary get home repair. The complete repair can be made with common black iron pipe (don't use galvanized because of the possibly toxic fumes) with a local welder fitting the water injection pipe to the downside of the elbow.

Don't die from the lack of a simple--and inexpensive--repair.

Mitchell Bober
Sunny Lancaster, (Where most good advice is free.) VA

[Astronomertoo]

Your friends are correct, and concerned.
I want to remind everyone that a little carbon monoxide (CO) goes a very long way. It is sneaky, will make you think slow, acculmulates in the blood quickly because it readily displaces oxygen thru the lungs, and does not come out easily, such that you do not know what is happening until you wake up either dead, or lucky that someone found you in time. Same thing happens in private aircraft, every year. The standard fix is a couple days in the hospital breathing pure oxygen, if you are lucky.
If you are near the exhaust leak, and must run the engine to get to safety, keep everything open to ventilate, hold your breath below, and do not loiter in the area. The particulate is not the safety problem.
It does need a permanent fix or replacement asap.
I have attended many safety meetings regarding CO poisoning issues and "lessons learned", and do not want anyone here to treat it lightly.
Bob C