19 Glasply Fuel Tank Replacement and Then Some

Figure I post so people that know more than me can tell me what I did wrong for next time. This time well its too late. I got some helpful information last year when I removed my I/O and went outboard. (Should of done the tank then)

19.5 Glasply
Belly fuel tank started leaking last week in July. Cut the floor on July 28th with hopes of being back on the water this past Labor Day weekend but I feel behind a little.

Tank was 28 years old and I'm surprised it lasted this long. I always said when the tanks leaks I'll put my fish box in the floor so I went for it.

Crappy before pic. Fish box on deck and was always a PITA to get over it to the helm.



Cutting the floor. Fuel tanks was foamed making it a ***** to remove. Stringers are dirty as hell but in good condition. No wood there also so saved me time by not needing to replace.


I would of loved custom tanks but due to my tight (self inflicted) dead line I got lucky and my local West Marine had (2) 35 gallons tanks in stock. Old tank said it was (76) but calculating volume after I pulled it was more like (60).


Test fit the tanks and starting to foam in the fish box.


Back half of the deck


Test fit battery box and little extension I added to hide the PVC coming from under floor.


Wiring mess under the dash now.


And as of Tuesday afternoon.
https://www.youtube.com/shorts/ZO1pqsKVdbY

I used poly resin for almost everything except the first layer in the fish box. I used epoxy and 1708 for the first layer. Then switched to one more layer of poly & 1708 then gelcoat.

Only have chairs to install, bleed the steering and hit the water.

If I had a choice to do it again I would just replace the tank and I would of been back on the water already. Not to mention all the damn hours living in the boat.

 

Vent the lockers, the plastic tanks and stuff is pretty smelly.

 

Did you use xps and the glass for the box? It is about 85% likely to delam.

 

Yes.

Previous 2 fish boxes I made the same way were fine after couple years. I sanded down the foam before glassing not sure if it helps any.

Commercial fishing guy on Maui uses it no isses yet. If it happens it happens and I'll switch to Divinycell since its available locally.

 

Remember that new tanks will stretch after the first fill, so there should be space to allow for expansion.

 

Didn’t foam them in.

Got 3 wedges holding them from moving. Hope that’s good enough

 

Are they held from the top too? That is required. You can block them to the stringers and on top to the deck or framing, but it is not enough to just put some wedges on the side. Straps are the preferred method.

 

Well I'm glad I added it in last min. Didn't know it was required but did it anyways. I didn't go with straps but I glassed in (2) 3/4" x 2" ply across the top of the tank where it looked like the straps were supposed to be. Sorry no pic before I closed it up but I drew in there I put the top support.

 

That should hold the tank in place. There are supposed to be access plates over the hose connections and the fuel level sender too.

 

I have a 6" over the fill/pickup/sender. I still need to cut the vent one towards the helm. Its a PITA to reach the sender but I can reach it. If it becomes and issue I may just change it to a larger plate.

So I'm think I'm legit.

 

I hate the arm senders on these tanks. I think I made it worse switching over from analog to digital, but I wanted the fuel tank output on the N2K network.

Switched it all over to Maretron, but I also hate their dead band riser setup and it cost more.

My fuel tank lockers are vented, but not enough. I tested the tank vapors as high as 4000ppm. Makes me paranoid the tanks leak, but they were tested in situ to 3psi for 12 hours no leaks.

Also, swan neck the vent line. It is a best practice against water in the fuel.

 

I'm not using the senders.

I only have a single Merc 175. Figure I just monitor the fuel burn through my NEMA 2000 network. I did route the wires up so I can hook them up later if I really want to but for now leaving it disconnected.