Leaking fuel tank on a bluewater 5800

So when I got to the boat today I noticed a pervasive diesel smell encompasing the boat... A few minutes later I realized that we had ~100 gallons of diesel that had spilled into the bilge. Figuring it was from a broken tank, we ran a pressure test, and sure enough the tank has a leak somewhere.

I have already talked with the manufaturer and they were able to identify that there is a small history (2 boats) that had leaks in the aft weld of the tank, so we are going to check that tomorrow with a borescope, if the leak isn't there then the only other idea is to run the scope through the tank and see if we can find the leak.

The problem is even if we can find it, I am not sure that we have any access to fix it. The way the boat is built other than the stern the entire tank is buried under cabinatry, tile flooring, encased by stringers, ect...

So the question breaks down too;

1) Is there a way, and does anyone have experience repairing leaking tanks from the inside?

2) Any suggestions on how to get access to the outside of the tank other than ripping out the entire interior?

If someone does have the experience doing a repair from the inside of a tank, please let me know. Compared to the cost of ripping out a tank we would likely be willing to fly you to New Orleans to effectuate a repair.

 

Measure the tank and have a pvc lining welded. That is a specialized job for swimming pools and chemical storage tanks. Using the proper material is essential.

Carefully prop that through the inspection hole, apply some Sikaflex to the top and fill the bag completely so it snugly settles, wait till the bonding compound has cured and you're done.....

 

First find out if the manufacturer is responsible. It may be covered by warranty or a recall.

 

The boat is just over 8 years old, so no warranty and no recall... Unfortunatly.

However we were able to remove a bulkhead and find a 3/8" hole in the fuel tank in the rear pannel just interior of a weld. So now the question is

1) Is it possible to patch the hole, or are we just asking for trouble down the line, and should bite the bullet and replace the tank.

2) If a patch is possible what is the best option? Current ideas are from the outside: weld an aluminium patch over the hole, epoxy a patch on, just use a tickened epoxy to make a patch
Or from the inside: Weld a patch on, pour an epoxy over the damaged area

Or do both and interior and exterior patch


Finally if we do decide to do a temporary patch how the F^@% do we get the current tank out, and get a new one in without ripping out the entire interior of the boat.

 

I like those Bluewaters,almost land a helicopter up top,great fuel economy at 8 knots yet capable of 25...but wouldn't fit in my slip.

Had a similar problem on a different boat,drilled it out to 3/8"-threaded the hole and put in a well epoxied bolt with a diesel proof gasket.
Then patched the hell out of the bolt with same epoxy putty.

Sold the boat,told the owner,saw him last year and 7 years later hasn't seeped a drop.

Worked for me,maybe for you.

 

There is a products called Stag, it is a jointing paste, used extensively in the oil industry.

Tap a thread into the hole, insert a bolt and seal with Stag. Make sure that the bolt is as short as possible to suit the job.

Another way for larger holes is to drill and tap a cover plate, apply the Stag again and set the cover plate down with metal threads. This is how many new tanks are set up for inspection ports, so there is no problen fixing leaks the very same wasy as an inspection port is installed, meets any survey requirement too if it was required.