CONTINUOUSWAVE

I have had a 2000 OUTRAGE 18 for [several years], and now I am in the finishing stages of a full refurbishment and re-powering of the OUTRAGE 18.

To get to the below-deck fuel tank is relatively easy. The center console must be unbolted and moved out of the way. Because I planned to re-wire all the electrical circuits, I just took the center console off the boat.

The aft cockpit deck [that covers the fuel tank cavity] consists of a single large piece. To lift or move this large deck section can be awkward and clumsy.

The fuel tank is not sealed in-place with foam or adhesive. It sits in a finished cavity on rubber pads, held in place with [metal] brackets above the tank. In my 2000 OUTRAGE 18 the fuel tank was made of plastic; it did not need to be replaced.

I removed the fuel tank from the fuel tank cavity of my 2000 OUTRAGE 18, and set it on the empty foredeck, having already removed the center console. There were 22-years of accumulated scum in the fuel tank cavity. The scum cleaned up nicely.

Thanks for the interesting look at the fuel tank and fuel tank cavity on the 2000 OUTRAGE 18 boat. The use of a plastic material for the fuel tank is a departure from Boston Whaler long-time practice of using a welded aluminum fuel tank. The aluminum tanks had a long service life in actual use, as long as they were not being held in foam saturated with water. The plastic tank in this boat seems to be holding up well after 23-years.

Regarding the metal bracket that holds the fuel tank in place: does Figure 1 show a metal bracket on the left, perhaps that long object with "18" written by hand on it?

The absence of any foamed-in supports surrounding the plastic fuel tank is also interesting. A number of owners of Boston Whaler boats with aluminum fuel tanks have altered the fuel tank support to eliminate the foam and leave the tank surrounded mostly by air, and sitting on rubber pads.

As noted elsewhere, the production epoch for this particular model was limited, and the total number of boats made was probably similarly limited. But the changes in the configuration of the fuel tank may have influenced Boston Whaler in their choice of materials in later boat production.

Also, the pattern of dirt on the fuel tank cavity sloping sides seems to suggest that perhaps the fuel tank bulged in places to make direct contact to the hull. Did you observe any distortion or bulging of the plastic fuel tank?

I believe Boston Whaler has been installing plastic under deck fuel tanks since at least 1999. I don't know if they were installed across all model lines but suspect they were. They seem to be holding up very well with few complaints. Owners are often put off by the odor of gasoline when consoles are opened due to the tendency of the tanks to allow fumes to escape at a higher rate than do the aluminum tank previously installed in our boats. We soon learn that the odor is harmless.

The first model I recall with plastic tanks was the V-22 Revenge in 1979. I did some initial research on tank alternatives for an owner sometime in the 2010's.

Jefecinco wrote:Owners are often put off by the odor of gasoline when consoles are opened due to the tendency of the tanks to allow fumes to escape at a higher rate than do the aluminum tank previously installed in our boats.

A tank made of plastic might be slightly more permeable than a welded aluminum tank, so the odor could be coming from some permeation of the gasoline into the plastic. Gasoline, particularly ethanol-gasoline blends, is a very good solvent.

The [plastic] fuel tank [in the 2000 OUTRAGE 18] is supported on its bottom by two-inch-wide wide rubber strips, three strips on each side of the sloped bottom, leaving [an air] gap all around the tank. The tank cavity [at the aft end] is not enclosed and is open to the stern of the boat. Water in the stern sump can flow around the tank; that is how sludge [that is seen in Figure 1] was created.

jimh wrote:Did you observe any distortion or bulging of the plastic fuel tank?

There certainly was evidence of the tank bulging and contacting the hull. [The bulging or distortion of the tank shape] as not bad, but I did repair some areas where the gelcoat had been eroded [by the tank rubbing on it]. The Moeller plastic fuel tank was fine. When I re-installed the tank, I added more rubber support [strips] bellow the tank and on the tank sides.

jimh wrote:Regarding the metal bracket that holds the fuel tank in place: does Figure 1 show a metal bracket on the left, perhaps that long object with "18" written by hand on it?

The long piece with the 18 on it is the factory rigging channel, which is similar to a piece of plastic rain gutter and sits on top of the fuel tank. [This can be seen in-situ in Figure 2 below.]



The metal retaining brackets are aluminum four-inch L-sections, two on each side. Between the metal brackets and the plastic fuel tank are rubber strips. The metal brackets are fastened with two screws to the sides of the fuel tank cavity.