Gas tank leak

[Matt1989Carver3807]

5/30/2021 From "out of the box". Start with a 140 gal tank from which about 75 gallons of gas was removed until the hose touching the bottom of the tank started sucking air. The hose was inserted into the fuel gauge sending port on top of the tank. A wood dipstick was inserted and it touched the bottom of the tank revealing a 1/4" of gas in the bottom of the tank.
The end of the tank appears to have some contour but I think "it is probably safe to assume the bottom of the tank is flat". I think that "it is probably safe to assume the fuel pickup tube is about 1/2" above the floor of the tank.
Based on these assumptions, is anyone aware of a liquid material which could be poured into the tank (like epoxy) and form a gas proof liner?? It might take several gallons to get above the level of the leak.
Further, one would have to fabricate and install another fuel pickup tube which would extend to 1/2" above the level of the "liner". This might be able to be inserted through a hole drilled in the deck as is the fuel fill hole. Would appreciate comments/suggestions.

[Viper]

I know it's not what you want to hear ($$$) but really the best solution is to remove the tank and assess whether it needs to be replaced or repaired. I wouldn't use epoxy for example, I doubt you'd be able to prep it properly, that much will also not be cheap, and will weigh quite a bit, you could be creating another problem. You also need to consider the type failure. If it's corrosion, another spot can open up later higher than your repair the headache all over again. If the leak is a cracked weld, the crack can keep migrating and leak again later.

There are services that spray the inside of tanks, don't know how successful that is but I know a few access holes have to be drilled to get into each section between the baffles in the tank. I know of someone that had it done but it was simply a measure to dump the boat on someone else. The evidence of a problem was pretty obvious though and ended up costing him money in the sale anyway. He ended up settling for what could easily have been the cost of a tank replacement.

For what it's worth, I've played a part in only one tank removal through the side of the hull. This was due to the boat's construction and lack of access from above to remove the engine. The rest were replaced by removing the engine with an A frame and resting the engine on the floor above the other one. Ya it's work but not that bad and totally doable. Can't even see it taking much longer than glassing in the side of the hull again, that comes with its own set of preparations and challenges.

[MajorV]

We are dealing with the same issue on 1992 33 aft cabin except on starboard side. We will be running with one tank this year just so we can at least get into the water. We'll follow your progress.

[V12diablo]

Would it be possible to install something like this: http://atlinc.com/custom-fuelocker-mari ... dders.html

I know we have used fuel bladders in aviation and racing for years. They could be built to fit the inside of the existing tank if you have enough access to cut in a opening to install it. Just a thought.

Jason

[Viper]

The problem is you'd still need to access the top or side of the tank to install a bladder. The other challenge is that the tank has baffles in it so there is a few compartments in there, not just one big empty space. You'd have to remove the baffles, and to do that, again, you'd need access to cut out the side of the tank and the baffles. The only thing you could do with those is chop up the tank so you can remove it completely to get a bladder in place. Still not an easy proposition and may turn out to be a deterrent to buyers if you ever decide to sell.

[Matt1989Carver3807]

Agree with Viper's sentiments above. With all gas odor gone and using the starboard tank exclusively we made a trip about 5 miles out onto the ocean and back with no fuel events or problems. No new news about the port tank project but thankful to be mobile again.

[Matt1989Carver3807]

Again thinking outside of the box, I am considering the overall situation for my boating goals here in San Diego. The local cruising scene realistically includes Oceanside, Catalina, and perhaps Los Angeles. The Channel Islands are otherwise not travel targets. San Clemente Island is a restricted military base and the other islands are basically undeveloped and distant. No interest in going to Mexico and being potentially being boarded by the local Police or banditos. This is vastly different from boating on the Great Lakes or the Great Loop cruising. Local ocean fishing trips locally are good.
I think perhaps the best overall solution to the leaking tank problem may very well be to remove the port tank and design a smaller tank which can be fitted into the port tank space. This would allow for some ballasting and provide an increase in range without having to remove the port engine. It might be possible to replace the 140 gallon tank with perhaps a 70 or so gallon tank which would be significant.
The process would involve 1. removal of the port tank and perhaps some of the motor exhaust piping 2. construction of a custom configured (aluminum most likely) tank and 3. construction of the necessary fittings and strapping features. The end result should be satisfactory from about all of the considerations. After all, this is an older boat with somewhat limited cruising potential. What you think?
Addendum == My checking around indicates the preference for an aluminum tank because plastic high profile tanks bulge when filled with gas and are not constructed with baffles.

[RGrew176]

Would seem to me that with a 70 gallon tank on the port side and a 140 gallon tank on the starboard side you would have quite the list with both tanks filled.

[Matt1989Carver3807]

Oddly, due to the overall heavy weight of the 38' aftcabin there doesn't seem to be much of a change in the handling, steering or "balance" of the boat. In practice there may be 2 or 3 tank scenarios. 1. Fill both tanks 1/2 full and there is no imbalance if fuel is drawn from both sides. 2. Fill both tanks full and draw fuel from the stbd tank only until it is 1/2 full and then switch to both tanks. 70 gallons translates to about 560lbs. or about 4 or so adult passengers. The listing appears slight with 140 gallons in stbd tank and 0 gallons in the port tank.

[RGrew176]

That is a good thing then the switch from a 140 to 70 gallon tank should not be problematic. Good luck with the project.