Fuel tank removal??

1983 34LRC with leaking port fuel tank. Was going to cut the deck to take it out, but am rethinking the solution. Suggestions include cutting tank up and removing and replacing with two or three others down thru the aft hatch, but has anyone used the engine room hatch to replace the tank. Needs to fit between risers on 3208N and short enough to get in the cabin hatch???. I think maybe a 20x20x66 inch tank would work. Going to mock up a box that size and try it. This would give me 100 gal. vice the 125 gal. but we can run the genny off the stb. 125 gal tank and break even. Weight difference may be an issue but if I can get the trim tabs to working that should take care of that. Any thoughts, suggestions? Thanks

My 34LRC has Detroit 8.2's in it; probably about the same size as your 3208's. I'd certainly hate to cut the deck open, as I suspect that may lead to strength issues. Please understand that I have not measured any of this at all; just guessing. There is a 2x4 vertical brace just forward of the aft hatch. If that brace was removed, I think the tank could be moved laterally to the boats' centerline, then forward to a position under the main hatch in the salon, then up & out. What went out could then come back in; ie same size tank. My tanks are too long to make the turn up & out of the aft hatch, but if the width would allow passage thru the engine's , I believe they could come out that way. Even if you had to remove an engine component or two, it would be less expensive & labor intensive than cutting the deck open. You certainly are having a fun boating season. How is your tx problem coming along?

My 37' is a totally different tank setup than the 34', so I can't remark on the best method other than cutting the deck open to get the tank out would be*my very last resort.

I'm with Chris, if there is no bulkhead between the tanks and the engines I would look at that really hard.* I know it's real tight*between the 3408's, but even if you had to take the exhaust manifolds off to clear the engines would be much preferred to cutting into the decks.*

Larry B

*

Why take the old tank out. I would use them as the frame/support for the new tank. When it comes time to reace.the tanks,it
will be with multiple smaller tanks, manifold together.

Raymond, did you consider taking them out right through the transome? *wouldnt be a very large hole and would make the tank replacement part easy, easy. * Wouldn't be my first choice because of the glass work but is probably a fairly easy repair for a good glass guy. *Do both tanks and the glasswork probably wouldn,t be much more??

Made the mock tank 20x20x68 vice the 22x17x77. This permitted it to pass between the riser on the engines to get it down the main saloon hatch, but 68 to long. Ran into the genny and couldn't move if over far enough to clear the genny. Binding on the risers. If we took the risers off the tank would probably go in. Going to check with it 10 inches shorter, now about 96 gal. With the shorter tank can probably make it a little taller and get back some fuel capacity. The height on the first mock up tank was limited do to getting it down through the hatch Reluctant to take the risers off but may do it. With my luck would twist off a stud/bolt. I doubt they have ever been off. Some would say they need to come off for examination/cleaning etc.

Because of my experience using the mock up tank and the engine room hatch which is 52 inches in length, I now have reservations about being successful in*putting*the tank thru a hole in the aft deck. Would have to cut a very long*hole to even get a shorter one in.


-- Edited by Fighterpilot on Thursday 19th of January 2012 07:07:41 AM

Phil Fill--considering your suggestion to leave some of the old tank in for support. How much do I leave. Something like cut it down, just leaving 2-3 inches up from the deck all the way around? Can't leave much more than that or I can slide the new tanks in. New tanks would have to be 2 inches narrower to get them past the engine manifolds, so would have to shim inside the old tank to meet the edge of the new tanks. Could leave the outboard side higher. Than do I strap them down? Hook straps to the existing higher outboard side and come over the top down to the inboard side to fasten? As of this moment am going with two tanks. Can position the connection between the two where it is accessible. If I use straps than the tanks won't require flanges on the sides but probably need something fore and aft. Your thoughts?

Fighterpilot wrote:
Phil Fill--considering your suggestion to leave some of the old tank in for support. How much do I leave. Something like cut it down, just leaving 2-3 inches up from the deck all the way around?

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*It would seem to me they would*act like the pans under the water heater or A/C* up in the attic.* Except with them there is nothing that has contact with the unit it is collecting for.* With these the new tank will be in total contact and possibly*hold water which could *lead to corrosion.* You have not mentioned what you are having the new tanks made of. If plastic, I guess it doesn't make that much of a difference, but if metal I think you are asking for trouble.

One other thing you might consider is the take some 1" or 1 1/2" schedule 40 PVC pipe cut to length*and cover it with the closed cell*foam tubing*that they sell at Lowe's to prevent freezing and*sweating. These would go across the bottom of the tank and allow air flow under the tank.* Easy fix to air flow under a tank.* C&C sailboats had a problem back in the 80's with this.* They built an AL*fuel tank that fit down in the hollow of the keel.*It had more shapes than a Plane Geomerty quiz.*They then foamed it in place.*It did make good uese of wasted space.*Well in ten to fifteen years they would start to leak due to corrosion as the foam would retain water.* Who'd thunk.* So this was the suggested way to install the replacement tank.* It worked great.

As they are now they sit on a slab of painted plywood. I have been wondering about what I could put under them since I am going in with new alum. tanks. Will remove the old tank unless come up with something to place under the new tanks and keep away from the metal to metal contact.

Fighterpilot wrote:As they are now they sit on a slab of painted plywood. I have been wondering about what I could put under them since I am going in with new alum. tanks.

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*The rollers could be made of 1/2" PVC pipe.* Schedule 40 is thicker and stronger.* That would work under the tanks and allow air flow.

I would think some pieces of starboard, 1"wide x 1/2 thick", or so, might work well; certainly won't hold moisture, or rot away

Picked up my tanks yesterday. Both 20 in. wide and 21 in. high. One 44 in. long and the other 20 in. long. Alum with 1 inch ID connecting the two. Vents in both. Got to get the installed tank pumped out and cut up. Maybe get pumped out this weekend.