Fuel Tanks

[titan22]

I had a Mandella with two fuel tanks molded into the hull. I want to do this with a current boat I'm building but the C/G says no way. I've found the resin that is impervious to gas and ethanol. How does Skater get away with it? Can I build one for personal use as opposed to retail sales? I

[PAR]

What resin?

[titan22]

The resin we found is Dion 49512 made by Riechold. It works, we've had a test strip of glass made with this stuff in a jar of gas for 2 years now. No problems. It's kinda hard to find though.

[Ike]

The Resin is not the issue with the USCG. Integral tanks are not permitted with gasoline. It is simply a safety issue. And the standard was taken straight from the ABYC industry standard so the USCG just borrowed it from the boating industry

[gonzo]

Integral tanks are structural members. I see the logic in it.

[Ike]

Absolutely correct. Integral tanks are structural members and that is why they are not alllowed for gasoline.

Sec. 183.550 Fuel tanks: Installation.

(a) Each fuel tank must not be integral with any boat structure or mounted on an engine.

(c) Each fuel tank must not support a deck, bulkhead, or other structural component.

[BATAAN]

Sec. 183.550 has reasons behind it.
This means when the boat hits the rocks and breaks up, the fuel stays in the separate tanks and out of the water, they can even be salvaged intact by cutting the deck or hull. Yes, worst case scenario, but it happens many times a year. Same reason no bottom connections allowed per ABYC, only siphon tube from the top. In a fire, collision or wreck much less likely to dump fuel in bilge. Obviously when engineering for ultimate strength with lowest weight, structural fuel tanks would make sense, but in the real world there are problems, so it's generally not done.

[rwatson]

Is this the case for diesel as well ?

[michael pierzga]

Dont know much about handling gasoline tanks on boats, as far as I know the tank details quoted are gasoline specific. Ive sailed well built metal boats having integral diesel tanks , tanks whose bottom is the hull plating with athwartships walls as structural bulkhead members and fuel crossover plumbing and fuel feed lines welded to the bottom of the tank wall, all my life. On this vessel each tank is separated from adjacent tanks by one frame span...400mm in this case ...with an additional diesel tank located in the keel root. . Ive never seen a portable, non integral diesel tank, other than day header tanks, on a metal vessel.

[CDK]

Originally Posted by rwatson

Is this the case for diesel as well ?

It should be.

I have quite a reputation questioning rules and sometimes ignoring them, but any integral fuel tank is a potential environmental danger.
And it is also a nuisance if you ever want to install something new, like a through hull fitting and decide to drill a hole.

[Ike]

Most of the rules that apply to gasoline tanks also apply to diesel with a few notable exceptions.
Integral tanks are permitted with diesel
On gasoline tanks you cannot have any openings below the top of the tank. This means no drains or sight tubes. But on diesel tanks, drains and sight tubes are permitted.

[michael pierzga]

Integral diesel or any non gasoline fluid tanks contribute to the seaworthiness of the hull.....a vessel with intregal tanks has in effect a double skin in the advent of holing . I don't see integral tanks on plastic boats...perhaps the fuel, resin combo is not reliable over time. It must be a challenge to fit large fluid tanks to a plastic vessel. What is the airspace between tank and hull requirement ?

You can build integral on FRP - it will be basically the same layup as the hull so quite heavy. Bulkheads aren't usually heavy enough to share in the duty. I think most FRP builders just don't fight it and build a seperate tank, and it's cheaper to just throw an aluminum one in there.

[GG]

Titan , i have done a few Skater tanks over the years using the same materials that Douglas Marine / Skater uses and in fact i purchase my materials from them, and the resin they use is Derakane with a host of other materials to do the job and this thread on my sig line will show the repair of the tanks i did on a 32 Skater which is the old Don Q Rum . Titan , even to this day Skater still builds there tanks this way and most likely they will never change .Titan, i was talking with a friend of mine who is a sales rep for Composites One , and during are conversation about doing the gas tanks he mentioned that S2 Yachts/Tiara was using Riechold in there build of the tanks which really was no different .....then using Derakane.