GB 36 classic twin diesel fuel leak

[Chartwell]

I have a 1992 GB36 twin engine which had fuel tanks removed (cut up) approximately 14 years ago due to leak. Replaced with 4 (2 either side) plastic type material tanks. No need to move the engines. Only downside is fuel capacity reduced from 1500lt to 1200lt. I can give you more information if you require.

[JosieWhales]

We replaced on 150 aluminum tank that had corrosion we found along the bottom after removal.
The other side we cut inspection ports and used por54 to coat the complete bottom and 4 inches up all sides.
We had easy access to the side (kinda) and made those out of pieces we cut from the old tank from the other side.

[Captainv40]

Originally Posted by Tigress

Hi, GB36 Classic owner who had this done about 5 years ago by American Tanks out of Southern California. They did not have to remove engines or ANY other gear. They neatly cut up and removed the old tanks, thoroughly cleaned the area, and dropped two new manifold-connected tanks in place of each old tank. Nice work, but be prepared to open that wallet wide!

Talk to Vince or Carlos of American Diesel Tanks in San Diego. https://americandieselcorp.com/ They replaced the 2 X 300 gallon tanks in my Grand Banks 42 Classic last year & did a terrific job. Tore old tanks out w/o removing engines & replaced with stacks of aluminum tanks with little loss of capacity. And did so in my own berth. I highly recommend them.

[Scrib]

I have done a tank replacement on a GB 36 myself. It was a single engine boat but I don’t see a lot of difference of doing the job on a twin. The engines are more or less forward of the tanks so getting the old tanks out piece by piece is no big deal. It’s a little bit of a big deal to empty then cut the tanks up but it is totally manageable. Took me, working by myself about 3 hrs each to cut out the tanks … and 20 sawzall blades! My tanks were nearly full of course, so I bought a 175gal tote off Craigslist and was able to pump the fuel out of the tanks and install the new tanks one side at a time. The tanks pumped nearly dry due to the shape. A gross of bilge mats was handy to have. I had 4 tanks built to replace the original two so installed 2 tanks each side in a pancake design. It worked out great and didn’t lose any tankage. I have lots of pics of the job and am happy to share. I might even still have the drawings & specs of the new tanks. Send a PM if you want/need more details.

[River Song]

Originally Posted by Chartwell

I have a 1992 GB36 twin engine which had fuel tanks removed (cut up) approximately 14 years ago due to leak. Replaced with 4 (2 either side) plastic type material tanks. No need to move the engines. Only downside is fuel capacity reduced from 1500lt to 1200lt. I can give you more information if you require.

Yes, I would be very interested in learning more.

[MVCalypso]

Last year I replaced the fuel tanks in my 1984 Island Gypsy (twin Lehman 135s & outboard fuel & water tanks). The engine room layout is similar to the GBs. Moreover, I suspect the major project tasks are not really specific to the trawler brand & model.

When researching the project, I found that most seem to opt for cutting up and removing the old tanks, then replacing them with multiple smaller tanks, which are plumbed together. I found both pros and cons to that approach.

I opted to go with a less common approach: We cut approx 6'x3' access panels out of the hull sides, removed the old tanks in one piece, custom built new one piece tanks and slid them in from the outside. Then we re-laminated the hull and painted the top sides.

The advantages I perceived were: No need to remove engines and mess with many engine room systems along the way (which can be many man-hours and hence $ costs), no loss of fuel capacity, avoids multiple tank inter-connections (which would be potential points of failure), and finally, aesthetically the repainted topsides made her look new again.

Interestingly, the (fixed) price quotes for both approaches were within $2k-$3k of each other. On that size job, that's a minor amount. Neither approach is inexpensive.

I think the choice of approach would be heavily influenced by what yard skills are available near you. I have a yard nearby that had done this specific task before, who also builds custom (mid 40ft range) carbon fiber racing sail boats - so I was confident in their lamination skills. Some other yards in my area would not consider the surgical approach.

I just wanted to mention this approach as I didn't find it a common method for smaller trawler tanks. It's more often used on larger vessels (I understand it's often used to replace large engines).

If you'd like more info, I'd be happy to provide it.

[Comodave]

Lots of people here don’t recommend that approach because for replacing the fuel tanks. But it could certainly work if you have a really good fiberglass guy.

[MVCalypso]

Originally Posted by Comodave

Lots of people here don’t recommend that approach because for replacing the fuel tanks. But it could certainly work if you have a really good fiberglass guy.

It's not my intention to recommend this for everyone. Just wanted to offer info from someone that's been through it in case someone wants to consider it.
I do think it's worth considering - no matter what the eventual decision is.

It took me lots of study and consideration before I decided this was the best approach for my particular situation. Yes, confidence in the engineering and the trade skills of the FRP crew are crucial.

It was scary to see the first access panel cut. OTOH, the new tanks, their mounts, and the hull are now all better than when she was delivered from the factory.

[Xlantic]

Could you share some photographs?

[Aurora53]

I was looking at a GB 36 that had tanks that needed to be replaced. I was thinking about buying and doing a major refit. In my research I came across John at Oxfords Yachts in Maryland. He’s a Grand Banks specialist and is a wealth of knowledge, and a very nice guy. He has also made a bunch of YouTube videos


https://oya.com/boat-repairs-and-mai...ks-fuel-tanks/


Good luck with the project
S

[MVCalypso]

Originally Posted by Xlantic

Could you share some photographs?

I took lots of pics and kept a project log during the process. I'll have to figure out how to post pics here, but I suspect I can do that.

If folks are interested, I could start a new thread (so as not to hijack this one).

As a new comer to posting here, I could use some guidance re what section would be best for such a tale - here? General maint? The Island Gypsy section?


Are you interested in any a particular aspect of the repair approach?
If the topic isn't of general interest to the group, I could privately send you a summary.

[Comodave]

Originally Posted by MVCalypso

I took lots of pics and kept a project log during the process. I'll have to figure out how to post pics here, but I suspect I can do that.

If folks are interested, I could start a new thread (so as not to hijack this one).

As a new comer to posting here, I could use some guidance re what section would be best for such a tale - here? General maint? The Island Gypsy section?


Are you interested in any a particular aspect of the repair approach?
If the topic isn't of general interest to the group, I could privately send you a summary.

Starting a new thread would be best so that in the future people can find it and see what you did. As to posting photos, it is pretty easy. Go to the home page and there is a section on how to use the forum. In that section there is a sticky post on how to post photos.

[MVCalypso]

I created a new thread for any interested in my tank replacement project.

https://www.trawlerforum.com/forums/...ml#post1173891

[nhislander]

Given your location, you should check out Triton Liners. The owner lives in Jupiter FL... Assuming they can access the side (or top) of your fuel tank they actually go in and weld/build a new fuel tank inside your existing tank. Again, they just don't fix the leak, they actually line your existing tank with new aluminum, install new baffles, etc... Your tank will be stronger/better than when it was new. I just had this done on my 2020 Beneteau Swift Trawler 44 and they did a great job... Clean and professional. Typically far less expensive vs. removing/replacing with new tanks.

[River Song]

I would love to have it done in my own slip. I did not realize that was a possibility. Thank you.