Fuel tank and floor repair

[joshmjosh]

Hey guys just want to go over my repair plans to make sure I haven't missed something. I'm a surfboard manufacture by trade but never done anything with boats.
Fuel tank was cut out by marina. They will be fabricating a new tank and foaming it in. The hole is 24x41".
Plan of attack
Grind gel coat down around hole 3" around edges
Cut 1/2" marine grade ply to size. Coat with poly resin And 1 layer of chop strand mat
Run 2 1x4 from stringer to stringer and coat them with same poly and mat, also run a 1x4 inside hole edge to support front edge of new floor.
Counter sink screws and screw new floor down to supports.
Fill crack area with a thick microballons resin mix.
Layer 3 layers of chop strand and roll out bubbles. ( each layer separated)
Sand smooth the gel coat.
The majority of my hole will be hidden under neath the center consul.
I also have UV cure polyester resin and curious as to if I can use it to speed my lamination process up.
Anything I need to rethink or change?

 

[GT1000000]

Re: Fuel tank and floor repair

Hi and welcome...
Most of your plan sounds good...
Make sure the screws you use are stainless steel and you drill pilot holes and pre thread with regular steel screws to prevent from snapping the heads of the SS screws off...also use something like 3M 5200 on all the screws to prevent any water intrusion...
Can water ever get to the cavity where the fuel tank is?
If not then foaming is OK.
If water can get in there, then I would not recommend foaming it in because it will cause the tank to corrode when the water gets trapped between the foam and the tank...I would look to mounting with mechanical fasteners, in that case, leaving lots of air circulation all around...that is assuming a aluminum tank
You can use the UV cured resin, but it is not absolutely necessary...plus, doing wet on wet laminations is the preferred way to lay glass/mat, as that will give you the best possible adherence between each layer...known as a chemical bond, instead of a mechanical bond which is what you get when the previous layer has fully cured and you need to "ruff-n-scuff" it before the next lay up...
It will fully cure in few days any way, plus you are gel coating on top, to which you should use a wax additive in the final coat of gel or PVA coating on top of the final coat of gel to fully cure it...
And finally, be sure to leave yourself an inspection and maintenance hatch with access to the fuel lines and sending unit, if the need for repair or replacement should arise.
Good Luck and happy boating!
GT1M

 

[Bondo]

Re: Fuel tank and floor repair

Ayuh,.... Welcome Aboard,... I'd use wooden cleats, 'n ssteel straps to secure the tank,...

Foamin' it, Stops any hopes of good drainage,...

 

[joshmjosh]

Re: Fuel tank and floor repair

Thanks guys,
Ill make sure to do what you guys mentioned.
So i can layup 2-3 layers of chop strand mat at the same time? Im pretty sure that water can get into the tank area. There is a drain hole toward the front of the compartment. The old tank was plastic and was not foamed in. The marina that pulled the tank is fabricating a new 28 gal. aluminum tank and was talking about foaming in the new one. Being that im a surfboard manufacture i was listening to their procedure of securing tanks as ive not been around boat repairs. So it looks like will have to tell them to strap it instead.