Fuel Tank Installation

Happy New Year Cal Brethren! I am picking up my new 33 gallon, aluminum fuel tank tomorrow. As mentioned before, it will replace a leaky, 33 gallon French-made rubber bladder. The aforementioned bladder was simply laying under the starboard settee; unfastened, unbolted and otherwise unattached to our 34 Mark lll. I am seeking advice from those that have successfully tackled this replacement project B4. I know I need to attach the tank to the boat. I also know that airflow under and around the tank is essential. My question is: whether I should glass in a full platform, like under the water heater or simple stringers like those under the engine. Ideas? Cheers, Danny

I just replaced the tank in my 33. The original tank was a triangular shaped aluminum weldment. The original manufacturer was still in business and had the plans for the tank. I ordered one from them and went to install it but it must have been a slightly different size/shape because it didn't fit like the original. Even the original only rested on the inboard and outboard edges as it was flat on the bottom but located in the curve of the bottom under the port settee. I had researched the installation of aluminum tanks on the net and the apparent consensus recommendation was to isolate the tank from full contact to prevent corrosion. Google "aluminum fuel tank replacement" and you should find the article. Their recommendation was to make a flat platform to support the tank, but to attach 1" strips of starboard transverse to the tank at about 18" intervals. These strips should be attached with 5200 that is fully buttered onto the strips to eliminate any air pockets or crevices for moisture. Putting in a platform seemed overkill to me, after all, my original tank had lasted 25 years and corroded from the inside out. I planned to drop the new tank in just like the original, with some starboard on the inboard and outboard edges but as I said above, it didn't fit, rocking from the inboard front corner to the after outboard corner with the corners going up and down over an inch. I used a compass (drafting, not magnetic) and traced the curve of the hull at the forward, center and after portions of the tank onto some cardboard. I then used the cardboard paterns to cut PT wood ribs which I attached to the hull with a putty made from West epoxy resin and filler material. I reasoned that if the tank could be supported by three strips of starboard, then three wood ribs would also be OK. Thinking about it, the 27 gallons of diesel weigh less than 300 pounds and that weight is spread over about 600 square inches resulting in a load of well less than 1 psi on the botom of the tank. Allowing for a factor of 2 due to geometry approximations, that is still less than 2 psi. I couldn't conceive of anything that would happen to the boat that would stress the tank anywhere near the limits of the aluminum. The force on the hull would be about 10 times the force on the tank because it is concentrated on the three ribs. Still well within the limits of the laminate and substantially better than the original installation. When I dropped the tank in, it sat nice and flat and the only consequence was that I had to cut about a half inch off of the wooden shim that was mounted between the retaining brace and the tank. I know nothing about your boat, but this is how I did it in my 33. Hope it is helpful. Al 1974 Cal-25 #1693, "Sweet Mary" 1985 Cal-33 #85, "Short Wave" --- On Tue, 12/29/09, Danny <db… [at] easystreet.net> wrote: From: Danny <db… [at] easystreet.net> Subject: [Cal_Boats] Fuel Tank Installation To: Ca… [at] yahoogroups.com Date: Tuesday, December 29, 2009, 12:55 PM Happy New Year Cal Brethren! I am picking up my new 33 gallon, aluminum fuel tank tomorrow. As mentioned before, it will replace a leaky, 33 gallon French-made rubber bladder. The aforementioned bladder was simply laying under the starboard settee; unfastened, unbolted and otherwise unattached to our 34 Mark lll. I am seeking advice from those that have successfully tackled this replacement project B4. I know I need to attach the tank to the boat. I also know that airflow under and around the tank is essential. My question is: whether I should glass in a full platform, like under the water heater or simple stringers like those under the engine. Ideas? Cheers, Danny

Danny wrote: > Happy New Year Cal Brethren! > > I am picking up my new 33 gallon, aluminum fuel tank tomorrow. As mentioned before, it will replace a leaky, 33 gallon French-made rubber bladder. The aforementioned bladder was simply laying under the starboard settee; unfastened, unbolted and otherwise unattached to our 34 Mark lll. > > I am seeking advice from those that have successfully tackled this replacement project B4. I know I need to attach the tank to the boat. I also know that airflow under and around the tank is essential. My question is: whether I should glass in a full platform, like under the water heater or simple stringers like those under the engine. Ideas? > My only contribution to this is that gasoline weighs about 6.25 lbs./gallon (depending on grade). That's over 200 pounds of liquid. Imagine picking up an object weighing 200 lbs. and moving it abruptly around, like things in our boat do when we're in a sea. Make sure the tank is well secured so it can accelerate/decelerate at the same rate as the boat does when she is bouncing around. Imagine that you have been knocked down. Will your 200 lb. tank be secure in a position 90 degrees or more from its usual one? When I installed the holding tank in the schooner, I cut stringers to fit under it approximately. Then I squeezed out an ample bead of 4200 on each one and laid a strip of plastic film over it so it wouldn't actually bond. When the tank settled in, it squeezed out the sealer as a gap-filler so the tank was supported uniformly once the sealer set up. The sealer was NOT an adhesive in this application, just a gap-filler and cushion. Chris Campbell

One of our friends in the marina replaced his fuel tank this summer. The manufacturer recommended using a minimum 1" piece of hard neoprene rubber to serve as cushions between the hull and the tank. I found these folks here in Greensboro as a supplier, and saved him some $$ by ordering direct. He said they were very accommodating and he was able to buy more than enough and still save. They did not have a on-line sales, but their telephone order was received within days of placing the order. Check them out. http://www.southernrubber.com/

This is similar to what I did with my 60 litre tank. The old tank was cylindrical, so I cut down the U-shaped supports to flat so there was a T-shaped support, which I completely sealed with epoxy (the Thing you're trying to do here is avoid standing water next to the tank, which will happen with wood but not epoxy). Then I used 1/4" x 1" plexiglass battens on the bulkhead. Then I bolted the tank to the bulkhead (had the tank built with strong tabs on the top). Finally a L-shaped piece of plywood, again sealed with epoxy, screwed to the T-support to hold the bottom edge of the tank in place. There are a few pics at http://www.bcboatnet.org/boattalk/index.php?topic=628.15 Good luck! druid "Coatue" 1973 Crown 28 Al Waschka wrote: > > > [SNIP] > > I had researched the installation of aluminum tanks on the net and the > apparent consensus recommendation was to isolate the tank from full > contact to prevent corrosion. Google "aluminum fuel tank replacement" > and you should find the article. Their recommendation was to make a > flat platform to support the tank, but to attach 1" strips of > starboard transverse to the tank at about 18" intervals. These strips > should be attached with 5200 that is fully buttered onto the strips to > eliminate any air pockets or crevices for moisture. Putting in a > platform seemed overkill to me, after all, my original tank had lasted > 25 years and corroded from the inside out. I planned to drop the new > tank in just like the original, with some starboard on the inboard and > outboard edges but as I said above, it didn't fit, rocking from the > inboard front corner to the after outboard corner with the corners > going up and down over an inch. > >

Danny give me a few days I will go look at how we did it just a few weeks ago I will try to take pics but the tank is already in Dave Paulson Allergia Cal 334 Channel Islands Ca ----- Original Message ----- From: Danny To: Ca… [at] yahoogroups.com Sent: Tuesday, December 29, 2009 9:55 AM Subject: [Cal_Boats] Fuel Tank Installation Happy New Year Cal Brethren! I am picking up my new 33 gallon, aluminum fuel tank tomorrow. As mentioned before, it will replace a leaky, 33 gallon French-made rubber bladder. The aforementioned bladder was simply laying under the starboard settee; unfastened, unbolted and otherwise unattached to our 34 Mark lll. I am seeking advice from those that have successfully tackled this replacement project B4. I know I need to attach the tank to the boat. I also know that airflow under and around the tank is essential. My question is: whether I should glass in a full platform, like under the water heater or simple stringers like those under the engine. Ideas? Cheers, Danny

Damy Our fuel tank has 3 2x4 cut to the shape of the hull and to the angle of the tank. Then bonded to the hull .the plywood under the cushions has 2 2x4s to hold the tank down they are full size. Dave Paulson ----- Original Message ----- From: Danny To: Ca… [at] yahoogroups.com Sent: Tuesday, December 29, 2009 9:55 AM Subject: [Cal_Boats] Fuel Tank Installation Happy New Year Cal Brethren! I am picking up my new 33 gallon, aluminum fuel tank tomorrow. As mentioned before, it will replace a leaky, 33 gallon French-made rubber bladder. The aforementioned bladder was simply laying under the starboard settee; unfastened, unbolted and otherwise unattached to our 34 Mark lll. I am seeking advice from those that have successfully tackled this replacement project B4. I know I need to attach the tank to the boat. I also know that airflow under and around the tank is essential. My question is: whether I should glass in a full platform, like under the water heater or simple stringers like those under the engine. Ideas? Cheers, Danny