Fuel Tank Fastening System Retrospective
Posted: Tue Jul 05, 2022 4:24 pm
FUEL TANK FASTENING SYSTEM
I wanted something incredibly strong to hold in place the new fuel tank I was installing on my REVENGE 22 because I was not going to foam-in-place the new fuel tank. I didn't have a way to weld aluminum so I needed to utilize stainless screws, nuts, and bolts to construct the aluminum hold down structure for the fuel tank.
After the fuel tank was installed, I ran the boat for one season, purposely beating the heck out of it on rough water to test the strength of the fuel tank fastening system. At the end of the season I pulled the floor and found everything was still solid with zero movement.
DETAILS OF FUEL TANK FASTENING SYSTEM
NOTES
DETAILS
The fuel tank cavity is incredibly thin fiberglass so to add strength for the lag screws I ground through the gel coat and reinforced the area with West Systems epoxy resin and fiberglass. The tube structure was 1 x 2 x 1/8-inch aluminum square tubing. All of the aluminum angle is 1/4 x 1-inch.
There number of screws to get this done was crazy, but the structure is solid.
I can't remember the hard rubber material I used both to cushion the bottom of the tank to the hull and on the aluminum tie down system.
Each leg of the structure Is held by 2 x 2 x 1/4-inch aluminum angle through-bolted in place. You can see four bolts and nuts in the Figure 1 below where the leg at the top is attached.
The structure came out incredibly solid.
On each end there is 1/4 x 1-inch aluminum angle bolted. The bolt head can be seenin the picture below. The angle is bolted to the underside tight to the tank to prevent it from moving sideways or front to back.
Every contact point is cushioned with rubber.
Each end has two pieces of aluminum angle; one on each side of the square tubing. The angle has a lag bolt on each side bottom to the hull, the top is a countersunk screw so there is clearance to get a bolt over the screw head and through the square tubing in both angle sections.
FINAL THOUGHTS
I'm going to say that if I had to do a fuel tank replacement again, I would not go this route. I would foam in the tank.
I would cover the tank and foam with a thin layer of fiberglass to prevent water from accessing the foam and tank. It is incredibly hard to prevent water from accessing the tank area. If you don't foam-in the tank in you really need a way to inspect and drain the tank cavity.
This is easily done with by installing a 1-inch-ID drain tube at the bottom between the fuel tank cavity and the factory rear under deck fish box. Utilize a 1-inch drain plug at the fish box end to prevent water from entering the tube. Pull the plug to inspect the tank area and drain it if necessary.
I wanted something incredibly strong to hold in place the new fuel tank I was installing on my REVENGE 22 because I was not going to foam-in-place the new fuel tank. I didn't have a way to weld aluminum so I needed to utilize stainless screws, nuts, and bolts to construct the aluminum hold down structure for the fuel tank.
After the fuel tank was installed, I ran the boat for one season, purposely beating the heck out of it on rough water to test the strength of the fuel tank fastening system. At the end of the season I pulled the floor and found everything was still solid with zero movement.
DETAILS OF FUEL TANK FASTENING SYSTEM
NOTES
DETAILS
The fuel tank cavity is incredibly thin fiberglass so to add strength for the lag screws I ground through the gel coat and reinforced the area with West Systems epoxy resin and fiberglass. The tube structure was 1 x 2 x 1/8-inch aluminum square tubing. All of the aluminum angle is 1/4 x 1-inch.
There number of screws to get this done was crazy, but the structure is solid.
I can't remember the hard rubber material I used both to cushion the bottom of the tank to the hull and on the aluminum tie down system.
Each leg of the structure Is held by 2 x 2 x 1/4-inch aluminum angle through-bolted in place. You can see four bolts and nuts in the Figure 1 below where the leg at the top is attached.
The structure came out incredibly solid.
On each end there is 1/4 x 1-inch aluminum angle bolted. The bolt head can be seenin the picture below. The angle is bolted to the underside tight to the tank to prevent it from moving sideways or front to back.
Every contact point is cushioned with rubber.
Each end has two pieces of aluminum angle; one on each side of the square tubing. The angle has a lag bolt on each side bottom to the hull, the top is a countersunk screw so there is clearance to get a bolt over the screw head and through the square tubing in both angle sections.
FINAL THOUGHTS
I'm going to say that if I had to do a fuel tank replacement again, I would not go this route. I would foam in the tank.
I would cover the tank and foam with a thin layer of fiberglass to prevent water from accessing the foam and tank. It is incredibly hard to prevent water from accessing the tank area. If you don't foam-in the tank in you really need a way to inspect and drain the tank cavity.
This is easily done with by installing a 1-inch-ID drain tube at the bottom between the fuel tank cavity and the factory rear under deck fish box. Utilize a 1-inch drain plug at the fish box end to prevent water from entering the tube. Pull the plug to inspect the tank area and drain it if necessary.