Formula 233 update

[nitz]

I've gotten some more stuff done on my formula.

I am using these bulkhead panels from Compsys Prisma in Melbourne for my bulkheads and fish box. They are 2" foam core w/ 24 oz biax cloth stuck to them. You cut the to size w/ a bread knife and wet them out. They save a ton of time! Here they are installed:

The compartment in front of the fuel tank will be the fish box. I installed the fuel tank. I first wrapped the tank in plastic, then poured foam around the tank. Then I removed the tank and cut out the foam in the area of the keel so water could drain. Then the tank fits right into the custom fitted hole. The tank is coated w/ 3 coats of coal tar epoxy. I also epoxied PVC tubes through the stringers for the fuel lines.

Tomorrow I'll be glassing in the floor for the fish box out of some more Compsys panels.

[OReely]

Can't beat coal tar epoxy for the fuel tank. What are you using to hold the fuel tank down? Nice job on the pipes for the fuel hose.

[nitz]

Can't beat coal tar epoxy for the fuel tank. What are you using to hold the fuel tank down? Nice job on the pipes for the fuel hose.

I was thinking about bonding strips of Starboard to the tank right over the baffles, and letting the sole rest on top of that. Do you think that's a good way to go?

[bly]

I was thinking about bonding strips of Starboard to the tank right over the baffles, and letting the sole rest on top of that. Do you think that's a good way to go?

No starboard is pourus and holds water.1 strike. Starboard is flexible so if your deck is not rigid then your fuel tank will be supporting the deck.2 strikes. That is a Big No in fuel tank installation. If you are using foam to hold your tank in place make sure No water ever enters that compartment. It will get between the foam and the coal tar epoxy and work its way to the aluminum. No closed cel foam is water proof. It is water resistant. Good luck and maybe Ill post my 233 redo here and stir some interest. My boat is now over 26 ft long and growing. I have a 30 in full flotation fiberglass twin bracket ureo ed into the transom after I found the original transom so full of water I cut it off. I also extended the bow to a pointy prow from the original blunt bow. I made the original center console a little bigger to todays standards.

[Mike Carrigan]

BLY is correct.

Dont allow water to collect in or around or on top of the foam you used around your fuel tank.

Your photo shows quite a large area for water to collect and stand.

If it were me, I wouldn't allow that.

[Cracker Larry]

Nice workmanship, but you are making a mistake foaming in the tank. The above comments are correct about the foam and water. It's not good to set a metal tank in foam, but many manufacturers do it. The coal tar epoxy will help some, but water will eventually corrode the aluminum. The tank needs to be mounted in a manner that water cannot get trapped next to it. Also, the tank should not rest on the bottom of the boat, it should be supported by the stringers. The hull bottom is not made to support that much weight.

Here is the correct way to do it http://www.yachtsurvey.com/fueltank.htm

Also, USCG regulations require that the tank cannot move more than 1/4" in any direction, including up. I'd weld 4 aluminum tabs to the top of the tank and secure them to the stringers.

Edited November 21, 2009 by Cracker Larry

[Mike Carrigan]

Nice workmanship, but you are making a mistake foaming in the tank. The above comments are correct about the foam and water. It's not good to set a metal tank in foam, but many manufacturers do it. The coal tar epoxy will help some, but water will eventually corrode the aluminum. The tank needs to be mounted in a manner that water cannot get trapped next to it. Also, the tank should not rest on the bottom of the boat, it should be supported by the stringers. The hull bottom is not made to support that much weight.

Here is the correct way to do it http://www.yachtsurvey.com/fueltank.htm

Also, USCG regulations require that the tank cannot move more than 1/4" in any direction, including up. I'd weld 4 aluminum tabs to the top of the tank and secure them to the stringers.

Very good.

As a manufactuter I dont wish to advise as to fuel tank installations where I'm not involved.

U.S.C.G. is very clear as to the subject.

It would be a shame to see all the work he's put into it and remain with the tank installtion he shows.

[OReely]

Starboard is made of high density polyethylene. It's not porous, but it's not a good choice for a holddown either. You'd be better served with a stiff material to block it in place or as Cracker Larry wrote, tabs welded to the tank that could be bolted to the stringers.

Coal tar coated tanks will last many, many years whether installed in foam of not. I've repaired boats that were 15, even 20+ years with coal tar coated aluminum tanks that didn't leak. I've pulled tanks out of a 20 year old boat that had no coating on it that wasn't leaking, although it was severely corroded.

Am I say that you will get 20 years out of a tank? Definitely no, I'm not. There are too many variables. I'm just pointing out that they can last that long. 15 years is not an unreasonable number to use for an average tank, regardless of how it's installed.

Today's urethane foams used in boat building are not open cell foams. They are not like a sponge but they can hold water in voids created during the blowing process. If you are in an area that sees freezing temps, the freeze-thaw cycle could lead to small degradation in the foam over time.

Edited November 21, 2009 by OReely

[Mike Carrigan]

The U.S.C.G. publishes THE BOAT BUILDERS HANDBOOK.

Fuel tank installations are well covered.

If it were me, and it's only one man's opinion, I think I'd go there and take a look.

N.M.M.A and A.B.Y.C. also.

Info is probobly easier obtained the the C.G. though.

Surroundong a tank with foam, proper installation of the tank, how it's held in place, movement acceptable, perhaps a lot of information that is free, very instructive, and maybe good to know in your situation, at the stage your at.

It's only a suggestion.

[Sandy]

I believe the foam cut away for the tank custom fit will be considerably more porous with the surface skin removed unless those surfaces are somehow carefully completely resealed. It looks like you are doing a great job and I applaud the care to allow drainage under the tanks, but I too have some inexpert concern about the foam . If any foam is supporting the tank underneath , consider also it will eventually crush to some degree.