Getting (fuel) tanked

Most powerboat problems can be traced to two areas: fuel and electrical.

On our 22-foot project boat, Swamp Yankee, we tried to reduce potential fuel issues by properly installing the tank. (Ethanol issues are a subject for another day.)

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Atlantic Coastal Welding built the baffled 65-gallon aluminum tank. It is the second tank in this Sisu, a workboat in its former life. When we started the project, boatwright Charlie Koller carefully inspected, tested and scoped the tank, giving it the thumbs up. He sanded the exterior and applied several coats of Awlgrip epoxy primer.

We also repositioned the tank from the aft bilge to the center compartment to better balance the boat. “They call it mass centralization,” says Charlie. “You want to get all the mass out of the ends of the boat. All the weight in the center.”

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We’re also adding more weight to the transom in the form of a 150-hp 4-stroke, which weighs almost 500 pounds, more than the lighter 2-stroke that used to push her.

The tank sits on six 1-1/2-inch L-shaped plywood chocks with hard neoprene glued on for chafe protection. The tank should remain nice and dry. The chocks will keep it off the hull, and a small channel running down the centerline should drain any water to a bilge pump located aft. Foaming in a fuel tank can trap moisture against it in the form of condensation, which will cause corrosion and shorten its life.

Charlie made the chocks by gluing together 3/4-inch plywood with West System epoxy. The chocks are glassed in place with a couple of layers of 1.5-ounce mat and vinylester resin, then coated in epoxy primer “because everything else is gray,” Charlie says.

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Charlie also screwed two plywood/neoprene standoffs on the forward bulkhead to ensure airflow around the tank. “We like air space,” he says. “The owner is anal about air space.” (I think he’s referring to me.)

A piece of aluminum angle bolted to existing glass flanges runs across the top of the tank to hold it in place. “It’s not going anywhere,” he promises. He also repositioned the fuel pickup to the aft end of the tank and cut a pathway for hoses.

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Charlie then installed a watertight hatch and inspection port to give access to hoses, the fuel pickup, sender and more.

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Fuel tank installations ain’t particularly sexy, but they are important.

10 thoughts on “Getting (fuel) tanked

  1. It is a small point, but i believe tat the ABYC requires the neoprene to be glued to the tank not to the support. The intent is to be sure that water cannot be trapped between the aluminum tank and the support. But is is a very nice looking installation.

  2. Kudos for not encasing the fuel tank in foam but otherwise this installation is not good practice. Since the bottom of a boat flexes, fuel tanks should not be supported off the bottom, particularly at concentrated points as with this installation. Instead, the fuel tank should be supported off the stringers or transverse frames where the flexing is much less.

  3. I might have missed something, but I was just wondering if that is what appears to be some type of composite materials being used on the side decks and bow area? (the tan areas) I am getting ready to remove my teak covering boards and re-do the decks of my 34 year old Pacemaker and looking for ideas. Thanks in advance for an help and advice.

  4. I agree with Mr. Pritchard.

    You’ve got six touch points for 500 pounds of moving weight….when you’re falling off the front sides of four footers you’re going to be putting a fair amount of stress on the hull bottom.

    I do like the placement though. With that amount of mass forward you could probably get away with not using trim tabs….is that what you’re hoping for?

  5. I guess the six touch points depend on how strong the bottom is. I note they are closer to the verticals outboard and the keel on the centre line so in theroy should be stronger there. Ie not in the middle of a flat surface. But I agree that spreading the load a little more may have been prudent. The tank may not flex as much if the baffles are welded in place thus decreasing flex in the bottom of the tank? Also having any sort of non crucial mass in the ends of the boat increases pitching and instability. That’s be known in yachts for some time. Concentrating the mass centrally is smart move and will no doubt make for a more comfortable ride.

  6. Anything but wood for the tank chocks. If you want to leave that boat to your kid’s kid only put stuff in that ain’t gonna rot! I don’t care if it is glassed over or epoxy saturated. Same for the truly dumb idea of putting wood reinforcement under through hull sea cocks. Fuel tanks are one of the biggest problems in a restoration and it is pretty much impossible to spend too much time to get it right!

  7. Oh my goodness! Amazing article dude! Thank you, However I am having troubles with your RSS.
    I don’t understand the reason why I can’t subscribe to it.
    Is there anyone else having similar RSS problems? Anyone who knows the solution can you kindly respond?
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