Air venting question

[landboater]

The houseboat I'm restoring HAD the Chrysler 318 inboard, which I removed and converted to an outboard set-up. Now the engine "room" or area can be used for storage. The question I have is: with all sources of fuel and engine related carbon monoxide issues OUTside of the boat now, do I still need the air vents?
The generator and fuel tank will be on a shelf-like platform extending out from the end of the transom. It seems like a good idea to keep them for fresh air, but I was thinking about covering the existing holes (for the factory air vents) and installing deck lighting in there. I will probably eventually have a small room enclosing the fuse panel and batteries etc. so I will vent that small area.

 

[jonesg]

Re: Air venting question

Where will the gas tank for the outboard be?
If its below deck you need the venting.

 

[Stachi]

Re: Air venting question

my boat has an outboard with the 30 gallon fuel tank below the deck....no venting was built in it from the manufacturer...boat pictured below

 

[RickJ6956]

Re: Air venting question

my boat has an outboard with the 30 gallon fuel tank below the deck....no venting was built in it from the manufacturer...boat pictured below

Are you sure? Without a tank vent a vacuum would build up inside the tank and the fuel won't flow.

 

[Stachi]

Re: Air venting question

Ofcourse my TANK has a vent...the OP is talking about the blower vents that he has from the inboard engine he removed....

 

[H20Rat]

Re: Air venting question

Ofcourse my TANK has a vent...the OP is talking about the blower vents that he has from the inboard engine he removed....

IIRC on that boat there are some gill like things on the sides that are meant to work as air scoops. The back IS vented, it just isn't very obvious, and doesn't have a blower. (used to have a very similar boat)


At least as the OP is concerned, he said no fuel will be stored in there. No fuel, no engine, no need for venting. It wouldn't be a bad idea to have venting if you have a battery in there, but I don't believe that is actually a regulation.

 

[Stachi]

Re: Air venting question

IIRC on that boat there are some gill like things on the sides that are meant to work as air scoops. The back IS vented, it just isn't very obvious, and doesn't have a blower. (used to have a very similar boat)


At least as the OP is concerned, he said no fuel will be stored in there. No fuel, no engine, no need for venting. It wouldn't be a bad idea to have venting if you have a battery in there, but I don't believe that is actually a regulation.

they are not vents on my boat.....they are dummy pieces,nothing but fibreglass behind them... on the Bayliner inboards they are vents....

 

[H20Rat]

Re: Air venting question

they are not vents on my boat.....they are dummy pieces,nothing but fibreglass behind them... on the Bayliner inboards they are vents....

wierd! mine was a year or two newer and had the openings..

 

[tschmidty]

Re: Air venting question

The venting refered to for a gas tank is the smaller tube running usually to the transom. The air vents actually vent the bilge and are needed for two reason, to provide air to the engine and to remove any gas fumes in the bilge which could result in ignition/explosion. There are technically not required just for the gas tank since if there is no engine, not much chance of ignition, although I personally would always want my bilge vented.

So no, the OP does not necessarily need venting in that space anymore if the gas tank and generator are outside.

 

[jonesg]

Re: Air venting question

coast guard regs.
http://www.in.gov/nrc/2419.htm#13

46 CFR 25.40-1 Tanks and engine spaces
All motorboats or motor vessels, except open boats and as provided in paragraphs (d) and (e) of this section, the construction or decking over of which is commenced after April 25, 1940, and which use fuel having a flashpoint of 110xF., or less, shall have at least two ventilator ducts, fitted with cowls or their equivalent, for the efficient removal of explosive or flammable gases from the bilges of every engine and fuel tank compartment. There shall be at least one exhaust duct installed so as to extend from the open atmosphere to the lower portion of the bilge and at least one intake duct installed so as to extend to a point at least midway to the bilge or at least below the level of the carburetor air intake. The cowls shall be located and trimmed for maximum effectiveness and in such a manner so as to prevent displaced fumes from being recirculated.
As used in this section, the term open boats means those motorboats or motor vessels with all engine and fuel tank compartments, and other spaces to which explosive or flammable gases and vapors from these compartments may flow, open to the atmosphere and so arranged as to prevent the entrapment of such gases and vapors within the vessel.
Boats as defined in the Federal Boat Safety Act of 1971 built after July 31, 1980 or which are in compliance with 33 CFR part 183 are excepted from these requirements.

Boats, as defined in Federal Boat Safety Act of 1971, built after July 31, 1978 are excepted from the requirements of paragraph for fuel tank compartments that:

Contain a permanently installed fuel tank if each electrical component is ignition protected in accordance with 33 CFR 183.410(a); and
Contain fuel tanks that vent to the outside of the boat.

 

[landboater]

Re: Air venting question

Very good, thanks...I'll consider my options, which are made clearer thanks to you.

Roger (Landboater) named this because the boat I've been working on has been up on keel blocks and so far hasn't seen a drop of water...so I guess any boating I do is on LAND!
34' LOA 1969 Marinette "Rivercruiser" <--all aluminum 5052 grade.

 

[jonesg]

Re: Air venting question

Mine is an outboard with a 60 gal under deck tank, not only did I leave the vent hoses but I installed a blower, not required by law but whatever.

Blowers are cheap at $25 and work good to evacuate fumes, the old tank had a slight leak and I could always smell fumes.

The legal requirmements are minimal fool protection, I need more.