Fuel Tank replacement

[cooppat]

After filling the tank for the 1st time on my 74 20' sf, I discovered a fuel leak. I removed the fuel tank panel and found a saturated fuel cavity. The leak was on the port side of the tank just below the rear mounting bracket. the tank was in rough shape. Prior to filling the tank I drained the old fuel and filled it with 40 gallons of new fuel, determining that I had a 40 gallon tank. I have read several posts about the tank removal and replacement all very helpful. I have the tank removed and I have included several photos of the old tank and tank compartment. The tank was mounted to the side of the stringers with some rubber pads at the brackets, and the bootom of the tank had some rubber tapping material attached to it, and the sides were sorrounded by foam. The tank measures 24" x 60" x 8". The tank is flat and was resting on a flat fiberglass coated board, I have not removed this board yet. I am going to remove all the old foam on the sides, and clean up the area, and replace the fill hose and main fuel line.


My questions are the folllowing:

Is this the orginal tank?
What should I replace it with? I was hoping for 55gal
Should I remove the board?
Should I coat the tank?
Should it be foamed back in, from the posts I have read it sounds like I shouldn't.
How should I attach the new tank?

I hope these pictures are helpful.

http://img.photobucket.com/albums/v6...ankareaaft.jpg
http://img.photobucket.com/albums/v6...ankforward.jpg
http://img.photobucket.com/albums/v6...laftatleak.jpg
http://img.photobucket.com/albums/v6...tankbottom.jpg
http://img.photobucket.com/albums/v6...idebracket.jpg
http://img.photobucket.com/albums/v6...eedandvent.jpg

[Capt Chuck]

Happiness

Here's your pictures for you. Next time reduce the size to 640X480 pixels then send them to photobucket [img]/images/graemlins/laugh.gif[/img]

I would replace the tank floor with a new glassed in piece. New tank sized to the maximum (I think 70 gal fits in the 20 footer?) Replace all fuel and vent lines, prime and coat the tank (epoxy or cold tar) and foam in place. You can use a piece of PVC board or teak wood in the space between the stringers and the welded pad eyes on the tank.

Do it right the first time and Good Luck !!

[cooppat]

captchuck
Thanks for the reduction on the pictures, and the advice. Should I replace the tank with a flat bottom tank or sloped bottom? What is typical for a Seacraft replacement?

[FELLOW-SHIP]

Ha Happiness
Looks like you got you hands full. There has been several threads about replacing tanks on this sight under the general section and under the repair section. Most of your questions would be answered there just look back and hunt for them. There are a few things I would say if I had to do the job over again. I would coat the tank with a epoxy coating, I would still use the plastic trips on the bottom of the tank to elevate it as indicated in some of the old threads, I would not use foam that’s what causes tanks to go bad. I would replace the old wood platform with a new one, and I would use a flat bottomed tank again. I know you are thinking of increasing gallons but the way to do that is by stretching the length. The reason why I say that on tank length is because the SeaCraft is a veritable dead rise hull design if you go with a V shape bottom tank there will be a downward angle to the tank at the bottom towards the bow of the boat at rest due to the V shape of the hull in the bow is much greater than in the stern of the boat plus due to the change in the angle of the V your tank would not rest properly on the hull in all places from the bow to the stern.
FellowShip [img]/images/graemlins/wink.gif[/img]

[Capt Chuck]

Should I replace the tank with a flat bottom tank or sloped bottom?

I agree with "fellow-ship" go Flat bottom. The edges of the tank floor are beveled so the tank will lie flat. You need the space under the floor for the bilge to drain and breath under the tank.

[cooppat]

That's good advice I'm looking for a new tank now, the old tank had the fill hole about 39" down the tank almost inline with the hose, does the new tank need the fill in the same location, or can it be further back on the tank most tanks I have seen have them towards the rear, does this matter will it create trapped fuel in the line? Has anyone read this link about installing an aluminum fuel tank?

http://www.yachtsurvey.com/fueltank.htm

[FELLOW-SHIP]

Ha Happiness
That’s the way most of the guys have installed their tanks with the strips on the bottom of the tank to elevate it a little and using the 5200. I also added two L shape brackets in the front and back to insure no sliding around. As for the location of the hose I don’t think that I would move it back any farther than where it already is. Remember “Variable Deadrise” that means the stringers have less height in the back of the boat then in the bow of the boat. If you move the hose back you could have a clearance problem from the top of the hose connection to the bottom of the deck plate. You have the air escape hose that would keep things ok no matter where the hose connections to the tank.
FellowShip [img]/images/graemlins/cool.gif[/img]

[thedink9]

Happiness

Most local tank builders will epoxy coat for a small additional fee. I went with SP tanks. They are in NJ. They did a nice job and shipped to a local truck depot as well. Cost me $800 for 135 gallons. Dink

[SEAFARI]

I agree with S&P tanks, They do great work. You can order
a 3/16 thick tank for a few extra bucks also.

Rodney

[Scott]

and I'll agree again.
We talked with them at the AC boat show and they had come up with a very much improved method of mounting the sending unit ... not to mention a much improved sending unit ... this stuff, from what I recall, was all standard and gave the tank some real "Bling" [img]/images/graemlins/grin.gif[/img] Gucci all the way Baby !!!