Covering Built-in Fuel Tank?

[76SeaRay]

On my 76 Sea Ray, the original fuel thank was a "V" bottom aluminum tank that was foamed in place and covered with a screwed down plywood "cover" floor that was fiberglassed over with the rest of the floor. There weren't even any access ports for the fuel sender or hose connections. So, I plan to put in flush mount access ports for those. I am wondering if I should glass over the entire cover once it is screwed down along with the rest of the floor making it not removable in the future essentially a permanent install? The tank is of course brand new and it rests on neoprene pads which will NOT be foamed in place.

 

[Scott Danforth]

the screw down cover met the requirement for inspection access.

I have an access port over my tank, its a toe stubber.

 

[Chris1956]

I would recommend you just screw down the fuel tank cover, so access to the fuel tank is maintained. Tank senders often break, anti-siphon valves can clog. and water and dirt can get into the tank and it is easier to get it out with tank access.

I would make a cover out of plywood and cover it with glass cloth to seal it. Now screw it to the rest of the deck.

 

[ajcampbell31]

I'd go with glassing over the entire cover. It’ll give you a solid seal and make everything super durable.

 

[cyclops222]

If you LOVE the boat ? You have several choices to make.
I vote for a FLUSH surface, removable, gasket, NON pressure treated plywood. Sealed on all surfaces. With none rusting hold down hardware in cover AND the hull hardware. Very lightly grease the threads in the hull parts. I can live with that effort.

 

[76SeaRay]

This is a full cut and gut restoration so really concerned with future water intrusion. I am old enough that I won't be doing this again. That said, I have used all marine grade plywood covered with glass where the original design as near as I can tell was regular plywood and stringers were not covered completely with glass. The floor did not have wood plugs in the flotation foam fill holes originally and only covered with thin glass. Flexing over time caused cracks over the foam holes and water intrusion thus the floor and stringer rot. The fuel tank was originally foamed in place and so it added to water retention once the water got through the floor.

I like the idea of being able to remove the floor over the tank but worry about any water intrusion. The new tank won't be foamed in so that would allow any water through the removable floor to get to the bilge and not be held against any wood. The problem is how to "gasket" the removable floor to seal out as much water as possible. I guess a removable floor section would eliminate the need for access ports over the fuel line and fuel sender thus avoiding a trip hazard on the access port covers.

 

[Chris1956]

Gee, why ask for help?

 

[76SeaRay]

I was looking for experienced opinions, pro's and con's, as I can go either way at this point in time. Sounds like people have had success either way.

 

[Scott Danforth]

I would do a Nida core panel, and just caulk in place. No fasteners, no wood

 

[Pmt133]

My 84 has a removable wood hatch the size of the tank.... the tank could be removed in about 10 minutes (2 beer max) if it was already empty. I like having that level of access so I am retaining it for the rebuild. I'll add, it was one of the few places that was still mostly solid. That being said, I would not reccomend doing it that way as it is tedious to make it look nice. And I'll admit other than a sender there is no reason to need access to the tank more than fittings which could be accomplished with a small port....

 

[kcassells]

New tank install with deck over flush properly installed should last for years.
Proper hatch access installed for fuel gauge sender and fuel to engine. Most access lids for complete tank have a history of failure from mfg's and diy's.
JMHO

 

[Chris1956]

Gee, make the tank hatch out of dry 1/2 pressure treated plywood, and seal it with poly resin. If it needs more strength, see if you can use 5/8" plywood. It should last 10+ years.

 

[JASinIL2006]

When I did my boat, I glassed over the tank put in a round access port to get at the sender, etc. I figured if I really needed to get the tank out, I was probably facing a pretty big job and I'd just cut the deck to get at the tank. I'd rather limit the places where water can get under deck than leave a big access panel that I'll probably never need.

 

[Chris1956]

I have a hatch over the tank sender, however, the anti-siphon valve, fuel line and vent lines occasionally need maintenance. The hatch is not near any of those. The tank has a full cover secured by 8 or 10 screws and is caulked. The bilge drain runs under the fuel tank, so any water that leaks past the caulk or hatch drains into the bilge.

The most fun I had was that the fuel tank had galvanized fittings, and I boat in salt water. I ended up fabricating a new fuel tank pickup fitting out of a bronze garboard drain fitting, when the OEM galvanized fitting rusted away. Luckily the full and vent fittings are moulded into the tank, so all I had to do was change the hose clamps when they rusted away.

Bottom line... more access to the fuel tank is a good idea, IMO.

 

[76SeaRay]

My original fuel tank has a V bottom and was foamed in with a small plastic tube running from under the front bulkhead all the way to and under the rear bulkhead to the engine bilge. So the original design had no way for water near the tank to get out.

I had my new fuel tank made the same as my original. I put neoprene pad strips "vertically" on the V sloped bottom so they won't hold water. The space under the tank is open front to rear with a short 3/4' plastic tube with just enough length to run under the front bulkhead (drain in the front V berth walkway) and one under the rear bulkhead to the engine bilge. Any water that gets in the V berth area and tank area does get drained to the engine bilge. I had to build "vertical ribs" under the neoprene pads on the sloped bottom as the V tank doesn't make the same angle and depth as the hull under the tank so the pads wouldn't rest on the hull.

Sorry, very long way to say any water in the tank area gets drained to the engine bilge with lots of air space under the tank. I still don't like the idea of water getting in there but if it does, the tank area will drain and should dry out ok. All the wood is glassed. I plan to gelcoat the floor and may use removable boat carpet which would cover (hide) the hatch if I go that route.

 

[airshot]

With all the concern about water intrusion, perhaps keeping the boat out of the weather might be the way to go. My 1992 still has the original 1/2" plywood cover, covered with carpet, still solid with no rot. My boat stays covered when not in use, only water is a little spray on ocassion and a fan to dry things out before storing. Leaving things wet and storing will add to deterioration.