Bad Fuel Cell 1979 20 MA

[Vezo, Part II]

I was amazed to find nothing under tank to support it. Somehow they were able to get foam to expand less than half inch from floor in a couple of spots so that it was not making contact with floor at all. But you are 100% correct about foam holding water. Inspected tank to find no visible holes but in two places on aft end of sides, my buddy gently pushed on one corroded area and went right through. Both areas were located where foam was in full contact.

My biggest question is whether or not tank is original. 1979 MA, aft, (larger) hatch has a 5 inch square layer of glass only screwed into hatch for access to fill, vent and sender. Hatch has same hole with core removed. Reason is 90 degree fill is too high and would not allow hatch to sit properly. Major soft spot so I am recoring entire hatch and placing a Beckson plate over new fill. Do I need to have new tank built half inch shorter? Should I epoxy four half inch strips of mahogoney to place under tank?

You answered my next question of what type of foam to use when refitting. Thanks. Michael.

I have a few pics but cannot upload if anyone wants an email for the record.

[Bushwacker]

Hi Michael,

I don't think it's an original tank for a couple of reasons: 1. As previously noted, they never used foam at the factory. In fact SeaCraft brochures used to brag about not using foam, and they are one of the few boat builders that provided a removable hatch to allow for easy (at least on Sceptre's and Seafari's!) inspection and removal of the tank! They said it cost them more because then they had ventilate the bilge, but they did it anyway because it was the right thing to do. 2. Every SeaCraft I've seen had a thin (~1/4") piece of plywood covered by one layer of glass on the top, under the tank on top of the keelson. It looks like whoever installed that tank didn't know what they were doing removed that panel and thought the foam would suffice!

Some strips to hold the tank off the supporting panel are a good idea, but I think I'd use some sort of inert plastic like starboard or pvc board instead of wood that might rot. Don't use rubber - some rubber contains carbon that will create a galvanic couple with the tank and corrode it! And yes, the "right type of foam" is NONE!

As for changing tank size, I'd just give the compartment dimensions to the tank builder and let him figure out how tall it can be and still have clearance for the fill and vent hoses. The vent should be located on part of tank that's the highest when you're standing the boat refueling it. Not sure where that is if your fill port is amidships - the gas fill on mine is on stbd gunnel about 2' fwd of transom; vent fitting on my original tank is at front of tank on port side.
Denny

[Vezo, Part II]

Thanks Denny. My fuel fill is port about two feet forward from transom and vent just below. Not sure I understand the keelson part. This has a beautifully gel-coated box, more like a coffin, that is part of the entire floor liner, or deck, as did my brothers 1988 18. It will be cleaned, compounded and waxed while new cell is being built. Roughly $9/gallon last time I had one built. Want to get max in there so hoping for about 70 again.

She should not leak again for 20 years so thinking about adhering a few Starboard strips length wise, should water make it in. There is a half inch sized drain in starboard right corner, which was slowly draining gallons of fuel into my bilge.

On my 15 Whaler I have an 18 gal. above deck aluminum cell under rear thwart. This one was primed heavily, then painted Krylon Kitchen Appliance Almond which matches interior perfectly. No clue of cost of coal tar epoxy. Thanks Again, Michael.

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