multi tank fuel system design

[naturewaterboy]

Ike,

Is there a new standard for plastic fuel tanks? I remember seeing something about a new lower allowable permeability on them.

Definitely will get USCG approved tanks. Sure don't want to be out at sea and have a bilge full of gasoline.

El Sea - good points on the fuel fill above the deck - I plan to build up an inch or so to get my filler cap well above the deck to keep water out. As far as the vent goes, I don't know that I can get a vent up above the deck. My vent is now in the side of the hull - probably not a great place - even though it is about 3 1/2 feet above the waterline. I suppose I could get a line up into the side of the cabin - that would put it high enough to avoid any seawater.

[naturewaterboy]

Is there a book anywhere on marine fuel system design? I still have a lot of questions about my fuel system. What are the best vents to use? I need to turn some sharp 90 degree turns in my fuel fill - can I use copper or where can I find brass sweeps? I bought two 99 gallon XLPE tanks from Ocean Link, a Moeller distributor. I want to be sure I get them plumbed right. Anyone suggest someone I can contact for help on this?

[Ike]

Is there a new standard for plastic fuel tanks? I remember seeing something about a new lower allowable permeability on them.

Yes, there is. But the EPA is still working on it. But as far as you go, you can buy whatever is available. The standard is not retroactive. The lastest proposal is for charcoal canisters on the tank vent line to collect vapors. The current USCG standard for permeation is 1.2 grams of fuel loss in 24 hours per cubic foot of net compartment volume (if it exceeds that the compartment has to be ventilated. It's a safety standard, not an environmental standard.) The EPA had proposed 0.5, the industry countered with 0.8 and so it goes. I don't know exactly where it's at right now.

[naturewaterboy]

Thanks, Ike. I'm installing the Moeller tanks now. I would like to install some large radius (anything but a sharp 90) sweep fittings in my fuel fill line to avoid stressing the plastic fill fitting on the tank, and keep from putting too much bend in the hose. Any idea where I can find some brass 1.5" OD fittings, or is any other material acceptable?