Fuel tank question.

cobrapowersys

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1995 islander with original tanks. Aux tank pitted through, main tank holds fuel just fine. I know once the tank starts leaking it is time to replace so I was wondering If anyone knows any way to determine if there is water in the tank or to tell the condition of the tank without removing. That hull will be a huge pain in the butt to remove the main tank. But I will do it if necessary. Any recommendations. No need to tell me to replace the tank to be sure. I know that is the safest bet. More curious about any experience people have with this situation...
 

ROBERTH

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Just pulled my tanks, main and aux. Was not too bad actually to pull them. Just get all the fuel out. I removed the sending unit and used a 50' of 3/8" clear vinyl hose and siphoned into my cars/trucks.
I can ensure you, that if aux. tank is pitted through, the main tank is right near it.

My tanks were coated, but that coating did not last or protect very well. I have sanded off the entire coating down to bare aluminum, fixed the pitted spots with Marine Tex, resanded and am in the process now of recoating the tanks with Coal Tar Epoxy.

I installed 1/4" by 1" wide PVC strips to the bottom with 5200 instead of the rubber strips that cause a reaction to the aluminum and caused some pitting. This was the recommended procedure by David Pascoe.

Installed new hoses that are ethanol safe. Used a 2" PVC coupler in the 1-1/2" ID fuel fill hoses with screws through the hose into the PVC to allow me to pull the new hose through the hull. That went fairly well also.

Should finish coating top and reseal sending units this weekend. One new Sending Unit from Wema and then let the Coal Tar Epoxy cure for a week, then re-install the tanks.

This is my second boat where I pulled the tanks. 1st boat, the tanks were not coated from factory. No more pitting on it than was on these with the coating, so not sure the factory coating was worth anything. The first boat tank was a 38 gallon tank and 20 years aged. Had one bad spot and lots of less minor spots to use marine tex with.
The Grady tanks were in same shape at now 19 years, so seems the age for aluminum tanks to be pulled and re-coated. Actually, would prefer to do it earlier before some of the pitting occurs.

I highly recommend that you pull the tank and inspect/recoat it. Do not re-use the rubber straps due to the Carbon in the rubber is what reacts to the aluminum from what I was told. Save yourself a lot of $$ from having to replace the tank. They are not cheap.
 

cobrapowersys

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Sounds like I at least should pull the tank to check. That however will be a gigantic pain in the arse. There is a bulkhead blocking the tank. The tank is literally underneath the helm with no way out unless I cut that bulkhead out... Replace the tank and then reinstall the bulkhead and have it reglassed. Then I worry about the integrity of the hull if I cut that bulkhead out. I just don't see any other way to do it. Did you have that access problem?
 

wilson

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Haven't been on here in awhile, rehab 89 sailfish. Took out back (aux) tank, cut the rotted bulkhead between the two tanks out. The bulkhead wasn't glassed at the top, hmmm i wonder why it rotted. Next I removed the front tank. Glassed in a two tank support rails (looks like a railroad track) then remove the fuel filler hoses (cracked) had one big tank made from 5/16 alum/etched and coated. Then istalled it on the tracks after several strings of cured 5200 then screw pinned the sides of the tank. Cut a new filler out on the transom cap and kept the vent on starboard side. Had the tank made with three pickups, two for motors one for empty and winterizing and it's line has a s/s ball valve. So I got rid of all the fuel valves and rat's nest fuel hoses, after a 12 volt one month project I now have one fuel guage and a beautiful clean helm area. I replaced all thru hulls with s/s, I've heard the whole brass vs. s/s crap, bottom line I work in a chemical plant and we don't have one piece of brass here, all s/s (pipes, tanks) and we don't have saltwater but we do have Sulfuric and hydrochloric acid....so shut it. Two new hpdi 200's and a new 10k lb loadrite! Boat, trailer, engines and all maybe I have 45k in it and that's how iI did it.
 

ROBERTH

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Sounds like Wilson is on the ball also! Good job!

Removal of tanks in the Sailfish model I have is quite simple actually. Just removed the 2 floor panels and there they were. There was a divider 2X4 that kept them separated that was screwed into the stringers and easy to remove. The only pain in removal was the main tank was partially under the helm area and that is where the fill and vent hoses were. So had to go in under the helm area through the cabin. But, Grady did a great job on making accesses for the hoses and was able to get to them quite easily. The clearance was so tight though, I had to disconnect the hoses from the tank to allow it enough clearance to slide to the rear and out from under the helm.

Installing SS thru hulls, all new fuel fill, vent and fuel lines to ensure ethanol safe. I have to say, the hoses coming out after 20 years were in great shape, but who knows what the ethanol will do over time.

Also while floor panels are out, replacing the old Tempress deck plates with new one's from Tempress. Ivory color matched perfectly and the new one's have more supports under the round 6" plate and are much stronger and do not feel so spongy. Was hard to find these, but they are still available to match the originals.