Fibreglass petrol (gasoline) fuel tanks.

[PetterM]

Anyone know what’s involved in making petrol fuel tanks that’s integral to the hull? Presumably is a matter of using a special coating inside tank?

[Ike]

Integral tanks for gasoline are not recommended and in the USA and Canada are not permitted on new boats. I don't know what the RCD says. Plus that gasoline and fiberglass (FRP) do not do well together. FRP is not impervious, it is a semi-permeable membrane and gas (and water for that matter) will migrate through the laminate and collect in any voids or dry laminate eventually leading to delamination and leaking of the tank. Alcohol (ethanol) blended fuels speed up the process. See Much Ado About Ethanol http://newboatbuilders.com/docs/Ethanol.pdf for more information.

I would strongly urge you not to make FRP gas tanks, integral or otherwise. There are much better solutions on the market.

[PetterM]

My sentiments exactly, until I read an article in Superyacht Tender about the new Scorpion 8.5 Sport RIB “utilizing special crystic fuel-resistant resin” to make what I understand was integral fuel tanks.
Just wondered if there was such a product on the market or if this was an error in the text. Integral tanks for diesel is relatively normal.

[rasorinc]

just info http://www.incaproducts.com/site/why_plastic.aspx

[Ike]

Integral tanks for diesel are fairly common and have not had the problems associated with gasoline and ethanol. I have heard of fuel resistant resins but the cost is probably a lot higher. I haven't seen any reports or studies on how well these hold up. And then there is the little problem of whether it's permitted or not. I don't have a copy of the RCD 0r 1SO 10088 which cover this. but here is a link to the Boating Safety Scheme on Fuel SYstems. http://www.boatsafetyscheme.com/down...uide_chap2.pdf

Another consideration is that the RIB is probably an outboard and in the US anyway the fuel system regulations don't apply to outboard powered boats. As I said I don't know if the RCD is the same.