Bilge/Motor Room Blower Exhaust Port?

[GordMay]

You may have to get creative.
Do you have enough height (inside the coaming?) to install a short downward sloping run (reversed trap) to the transom mounted intake & exhaust clam-shells?
I’ve worked on several Corbins, but my “oldtimers” is blocking my memory for details. Is there any way to run a duct up the “pilot house” bulkhead?

[Extemporaneous]

Originally Posted by GordMay

You may have to get creative.
Do you have enough height (inside the coaming?) to install a short downward sloping run (reversed trap) to the transom mounted intake & exhaust clam-shells?
I’ve worked on several Corbins, but my “oldtimers” is blocking my memory for details. Is there any way to run a duct up the “pilot house” bulkhead?

Pretty sure that I could find a way to do that. When I get to the boat, I'll be looking harder at finding a place to install a regular cowl vent. I really like the idea of being able to turn it to blow warm air on those in the cockpit when it is wet, cold and miserable.
We'll see.

Thanks,
Extemp.

[bobfnbw]

Our endeavour 40 has a thermostat adjusted 4" blower mounted high in the engine room with intake and exhaust on the port side of the cabin using 4" duct.
Haven't done any heavy weather sailing yet, but the PO said he had no problems with leakage. The ports are covered with large plastic clamshell covers. Would have to take a lot of grey water to take on water. Would be nice to have covers for them, but do not. I plan on changing out the blower for something a bit quieter and less vibration one day, and using new duct. I also want to change the plastic clamshell vents to stainless, but its not a priority. Got lots to do before I can get to that.

[GordMay]

Originally Posted by bobfnbw

Our endeavour 40 has a thermostat adjusted 4" blower mounted high in the engine room with intake and exhaust on the port side of the cabin using 4" duct...

That would be a “Reverse-Acting” thermostat, where the switch “makes” on temperature rise.
This is an excellent control strategy, commonly used in commercial/industrial applications. Any Electrical or HVAC wholesaler will be able to source one (probably off the shelf).

[boatpoker]

Its a little scary to hear mention of engine compartment ducts terminating inside the cockpit. This is not where you want a fan pushing carbon monoxide.

[Sandero]

An open cockpit is not a worry for carbon monoxide in a sailboat.

My engine exhaust duct leads to a vent screen in a combing pocket. I've survived the CO for 23 years.

[boatpoker]

CO is buoyancy neautral and will go where ever the breeze takes it like down you companionway ! The affect of CO is also cumulative and takes about two weeks to clear from your bloodstream so a little bit on Mo0nday...a little bit on Tuesday, Wednesday and by Thursday you can be one sick puppy. The symptoms of CO poisoning are virtually identical to seasickness. Not something I would want to play with.

[boatpoker]

Carbon monoxide is buoyancy neutral and will go where ever the breeze takes it, like down through your companionway. The effects of CO are cumulative so a little bit on Monday, a little on Tuesday, Wednesday and by Thursday you are one sivck puppy and it takes about two weeks to clear from your bloodstream. The symptoms of CO poisoning are virtually identical to seasickess. I guess you can afford to loose more brain cells than I due to oxygen deprivation.

How about a fire in your engine room, do you want that toxic smoke sent to your cockpit too? How about diesel fumes, thats an aroma that I hear goes well with rum.

[Extemporaneous]

Originally Posted by GordMay

That would be a “Reverse-Acting” thermostat, where the switch “makes” on temperature rise.
This is an excellent control strategy, commonly used in commercial/industrial applications. Any Electrical or HVAC wholesaler will be able to source one (probably off the shelf).

I made one of these for an exhaust fan that I put in my house attic. I used a regular electric baseboard heater thermostat and installed normally closed relay down stream of it. When the temperature rises above the set point on the thermostat power stops going through the thermostat and the relay closes and the fan goes on and cools my attic. It made an incredible difference the interior temperature of my house in the late afternoon and into the evening on hot days. I'm sure that it will also add years to the life of my shingles. I tried to find the RIGHT kind of thermostat (which I'm sure are available) but I couldn't so did it this way. I don't think I tried that hard. Anyway it has worked flawlessly. Of coarse you have to use the right amperage relay.

Extemp.

[RBEmerson]

Originally Posted by defjef

An open cockpit is not a worry for carbon monoxide in a sailboat.

My engine exhaust duct leads to a vent screen in a combing pocket. I've survived the CO for 23 years.

Sorry, but that sounds a lot like the guy who jumped off the Empire State Building, saying at every floor, "so far, so good". Honest - Bad Idea!

[GordMay]

I'd agree with RBE on this one.
Don't mess /w CO - it can and will sneak up and KILL you.

[RBEmerson]

Or, worse, make someone just drowsy and "out of it" enough to let an accident in where an alert watch stander would avoid the problem.

Accident: A surprise without the fun...

[Extemporaneous]

Has anyone taken any CO readings?
Don't get me wrong, I clearly understand that you should NOT play with CO, I am just curious as to what ppm people are seeing.
We're not talking about running your exhaust through your cockpit, it is engine room heat.
I've been in many a generator room that has no CO present, oh ya, I've been in several that do.

Extemp.

[RBEmerson]

In the case of venting a bilge blower into the cockpit, it's not that it's a sure bet to kill someone because obviously it's not. OTOH, we had a close call when the mixing elbow corroded through. Obviously we lived through it but the potential for an unhappy outcome was there.

There are enough problems with a quartering breeze bringing exhaust over the transom or a dodger that traps exhaust fumes. In the former case, think about motoring downwind in a true wind only slighter faster than the boat's speed. In the latter case, while delivering a Tayana 37 and motoring into about 10-15 kts apparent, we had a problem with the dodger and bimini creating a swirl that brought exhaust into the cockpit, even while going to windward. The only fix was to open up the dodger, not a lot of fun in the Atlantic in early spring...

Add to those circumstances a forced draft with who knows what fumes (smelly or not) and... IMHO, not a good thing. Yeah, probably dumping bilge exhaust into the cockpit won't hurt anyone, but the price for getting that wrong can be rather steep.

[Extemporaneous]

Originally Posted by Extemporaneous

Has anyone taken any CO readings?
Don't get me wrong, I clearly understand that you should NOT play with CO, I've been in many a generator room that has no CO present, oh ya, I've been in several that do.

Extemp.

Come to think of it, most if not all had very good exhaust systems in these rooms, some even having almost one entire wall of motorized dampers behind louvers which opened when the temperature rose beyond a set point. Can't remember if there was CO detectors or not. Gord would likely know if CO detectors in Generator rooms are standard or not.

I digress. Oops.
Extemp.