Boat ventilation

I made a recent post asking if anyone knew how and where to put a ventilating fan in the bilge of a boat. Most of the answers I got were along the lines of, “I never heard of that before.” Well, mostly, I never had either but when you consider that gas fumes (heavier than air so then sink into the bilge) mixed with air in the bilge would make a pretty explosive mixture it made sense.

Here are quotes taken from the 2010 Minnesota Boating Guide and the Kansas Division of Wildlife and Parks:

Minnesota:

VENTILATION

Motorboats carrying or using any fuel that has a flashpoint of 110 degrees or less (like gasoline) in any compartment must be equipped with an efficient ventilation system to remove combustible gases. This system must consist of at least one intake duct that extends from the deck below the level of the carburetor air intake (or halfway to the bilge) and an exhaust duct that extends from the deck to the lowest portion of the bilge. The cowls of these ducts must be properly trimmed for maximum ventilation. A power-operated bilge blower is highly recommended and it should be run at least four minutes before starting the engine.

Kansas:

Ventilation

All closed-construction , fuel-powered motorboats must have ventilators to remove explosive vapors from engine and fuel tank compartments.

Be sure that the boat is well ventilated before starting, especially after fueling. Gasoline vapors are heavier than air and accumulate in the bottom of the boat, creating a dangerous condition.

Since I’m going to Kansas with my boat, it looks like I fall under this requirement so I’m still looking for a way to put in a power ventilator. Any boat with a deck above the hull would technically be closed construction as would any internal gas tank.

I’m thinking that this type of accident must be fairly rare since any gas – air mixture would be very explosive and we would be hearing about it in the news.

Food for thought.

here are some guidelines from the USCG, ventilation starts on page 30. I believe the key is that the built-in tank must be vented outside the boat, and that the tank is not in a sealed, non-ventilated compartment, as well as there is no engine (with starter) in the same enclosed compartment (like an inboard or I/O boat would have).
http://files.dnr.state.mn.us/education_safety/safety/boatwater/backyardboatbuilders.pdf

HRG

I would think if you where up on the great lakes or coastal waters you would hear more about this. Most of our fishing boats in central mn just are not big enough to require power ventalators.

USCG regs. if I remmber rite require a fan that will complete 1 complete air exchange. 4 minutes is a standard rule of thumb that it takes to do this.

Maybe talking to a marina that deals with bigger boats would be a good resource for this.

just wondering what kind of boat do you have? I am assuming you have a built in tank and not two 6 gallon tanks that you take out?
If you have a 16 to 22 ft boat, you should have a tank breather valve coming out of the side or back of your boat. Not sure how familiar with your rig you are.

Is this a new rule or are you new to boating, just got a boat and want to make sure you follow the rules? Never heard this question before and I am assuming it is for larger boats.
So, More info on your set up please

The boat is a 16′ Starcraft. There are plenty of pics of it on the series of posts I just completed on the rebuild. I just put a 12 gallon tank in and vented it to the port side. It sits in the open so there is plenty of natural ventilation around it and it is attached to a 50 hp four stroke Yamaha. Not really much of a threat as the permanently mounted tank puts way less gas in the boat than the two six gallon portables did. My boat always smelled like gas with those two. As far as regulations go, you can’t be more inland than Kansas, yet that is where the law seems stricter than our Minnesota law.

What it really looks like is that if you write the law vague enough you can decide whether or not you want to enforce it.

I agree that the rule seems to be aimed at larger, inboard boats with enclosed engines and gas tanks. I can never remember hearing that this rule was enforced against anyone.

Tomorrow, I’m going to talk to a couple of local marine dealers and see what they have to say about the situation.

Thanks for the feedback.

I think about this too when I see the guys in the cold cold winter days, with the propane heater cranking away in the boat, iirc propane is a bit heavier than air and can settle in the boat. I’m not sure how much wind it takes to clear the area out, I suppose it depends on a lot.

Quote:

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I agree that the rule seems to be aimed at larger, inboard boats with enclosed engines and gas tanks. I can never remember hearing that this rule was enforced against anyone.

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OK Jerry I have called Topeka quite a few times the last couple days trying to talk to Rob Ladner the man in charge of the Fish and Game in my region (Kansas version of the DNR). Anyway it is like what I said in the beginning you just need some way to ventilate the compartment. Like I think I said I have a vent pointing towards the bow on one side of my compartment and another pointing aft on the other side of the compartment and one of them has a duct tube that extends down almost to the hull. I also asked him about the vent for the gas tank (since I have such a vent on my boat) and he said that it is not necessary.
If you want to get any clarification on anything just give Rob Ladner a call at 785-273-6740 and ask for law enforcement.

I wonder if most of this verbage, is for boats that 1, have an inboard or inboards, in an enclsed area and 2, have sleeping quarters, below deck, where harmful fumes will likely go…

big G

Honestly I think that they left the regulation so vague to cover more boat configurations and to allow for some personal interpretation. With the idea that people like northstar will more than likely over equip his vessel rather than under equip it.

Another thing comes to mind they possibly had a little CYA in mind.