Fuel Tank sub floor replacement

[strick]

Six one half dozen or the other. I dont think you are going to get starboard to stick to 5200. The only way I got these starboard strips to stay in place was to laminate them to the base.



strick

[EagleOCNJ]

I agree that the 5200 likely wouldnt hold the starboard. I can manage what you did. Strick - did you cut out the stringers on either side of the back compartment?

I noticed when taking my tank out that the tank looked great for thirty years old UNTIL I looked under the foam that remained stuck to it. I then found a few deep craters.

There were rubber strips on the tank bottom. Again the tank looked mint on the bottom except under the rubber strips where I found corrosion.

[FELLOW-SHIP]

I did my tank exactly like David Pascoe suggested and went to Home Depo and found some semi hard plastic fence material and used it it had the correct thickness and W. What you do is fix the strips to the tank and then put Thick beads of 5200 along Both Sides of the strips which fastens the Tank to the Deck don’t use the 5200 to glue the strips to the deck. Don’t use rubber it will cause problems over time like foam will. My tank now just 5 years in but I don’t think I will ever have to look at it again. This needs to be a once in a boat life time project.

FellowShip

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My motto: Just for the Grins

[EagleOCNJ]

Another question: In my 1878 23 CC should the new floor piece actually touch the centerline stringer in the hull? The way have it cut now it is about a half inch above it. The deck is 29 inches and my new tank is 28.

I could trim it down since its not glassed or installed yet or I could put a strip of wood or starboard on the stringer. I dont want to trim the piece too much or it would not accomodate the tank width. I guess I could trim it 1/2 inch and it would lower it the same amt. - right?

I have the tank measurements vs. the compartment dimensions on as of now the way it is. Tank is 106 L x 28 W x 12 H plus two more inches for the fill. I have 15 inches to work with heightwise now and 29 width minus the epoxy build up at the plank to hull joint.

Any other last minute ideas before I get rolling? Also the new tank will have four metal tabs along each side to accept two screws in each. Im against foam but think that this may not be enough to secure the 1200 lb tank / bomb. How about a couple or four wood "straps" across the top glassed / screwed in?

By the way - I itch like a mofo!

[FELLOW-SHIP]

When I installed my deck for the tank I trimmed the bottom edges of the deck on a angle so most of the support was resting on the hull but the top of the deck was flush with the stringers then I glassed the deck to the stringers when I installed it. You will not have much room from the top of the fill hole to the bottom of the hull deck where the CC sits so try to make the strips of plastic as low profiled as possible with leaving enough room for ventilation as you can. You might want to first pre set everything in place to confirm you got enough room that the fill hose does not push the bottom of the deck up and it rests on it instead of the lip of the deck on the port and starboard. I did something a little different that most guys. I filled in the vent holes on the sides of my boat which permits air to circulate in side there. So I set up a vent inside my center consol for air to circulate around my tank and out through two small vent holes on port and starboard under the cap by the transom this is also a access hole for me if I ever need to go back in to mess with my connections or my tank fuel gage sending unit. If you don’t have enough room you could set up a vent or service hatch over the area that rubs.

FellowShip
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Just for the Grins

[Capt Chuck]

I think you worry too much about that center stringer. I mentioned before that I don't think it serves any purpose.
I wish Don Herman would chine in on this someday.
Look at this picture. You can see the 1/2 PVC pipe that my '78 had vs the stringer. Just make sure you leave yourself enough room for your fill lines and clamps. You don't want them rubbing the bottom of the deck hatch over them.

I like Fellowships idea of the plastic fence material between the tank and the tank floor for ventilation. You can barely see the little strips between the tank and the floor here. The only problem I might have is that my strips were rubber but I got the material from a guy out at the Nuclear Plant that said it was some special stuff they used around pipe fittings and flanges that would not effect the aluminum mmaterial?

Anyway, my tank had (6) of those metal tabs. I wedged a piece of teak between those 6 tank flanges and the stringer and screwed the tank tight right into the stringer. The 135gal tank has not moved since '95.

I like stricks floor the best!

[hermco]

I think you worry too much about that center stringer. I mentioned before that I don't think it serves any purpose.

I asked Potter about this once and he told me they were adding the center stringer to reinforce the keel that sat on the trailer rollers that were used back in those days. I don't see that it hepls because the keel is where you overlap the laminates when you build the boat anyway. You also have the extra material when you add the stringers. Seems to me the center stringer serves little or no purpose except to rot and get in the way of transducers etc.

[doug7488]

yeah, and play havoc w/ pumping the bilge dry!

[EagleOCNJ]

What I am actually trying to figure out is if the floor piece under the plywood should be set in place so it sits equally on the beveled edges of it (on the hull curve) and on the center / keel stringer. The olde piece does have a light imprint down the center of it from the stringer.

It actually looks to me like it was not secured to it but sat only a slight distance above it. I was considering just epoxying a strip down the keel stringer to make it connect to the tanks floor so it doesnt bounce around.

Sorry Im not getting it but its real important for me to understand before I move forward.

[FELLOW-SHIP]

Just look at the two pictures in this thread the deck does not sit on the center stringer. Your old tank deck was sagging in the middle because it was old and not laminated on the underside. Cut you wood with a bevel and glass it in place resting on the V of your hull design and snug it close to the stringers. This is not rocket science the tank itself has lots of its own support working for you.

FellowShip

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My motto: Just for the Grins