1988 20ft Overnighter 204-C Fuel Tank specs

Drill the hole with a stepped bit. Take the shavings off as you go. You would have to take the sending unit out so blow it out, get a vacuum in there on a piece of copper tubing or PVC pipe.

Stepped bits are the best way to drill holes in plastic. Drill bits and hole saws make a mess and sometimes crack the plastic. I drilled holes for my chum buckets and 5-gallon bucket garden planters. Works great.

Use a piece of butchers twine or electricians pulling tape, pick it up with a vacuum thru sending unit hole. Thread fitting on and pull into place. Put a stop on both sides of the fitting and leave it long in case you have to pull it back out.
 
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So we will have a similar setup to the OPs fuel filler hose setup. The difference being our Tournament 190 has fuel fill and fuel vent lines going to the front of the boat not the rear.

I wasn’t able to get a response from the OP but he used a coupler between the 90 degree elbow and rest of the fuel filler hose. I’m curious what kind of material matters. Does it need to be brass, plastic or stainless steel? Is there chance of static electricity building up? I know you ground the fuel filler neck if it’s metal but that makes me wonder about the coupler since it too will likely be metal. Should I find one with barbs or a lip, I found fuel filler specific ones with both design.
 
What is the purpose of this PVC pipe running the length of the fuel coffin? Why can’t the bow just drain straight into the coffin and then out into the bilge?

The reason I ask is because it’s causing some problems with shimming and spacing undernieth. I could make it work but if it’s not necessary, I’d cut the section that spans the coffin.

My only guess would be it would reduce the time it takes to sink the boat potentially but water can still get up to the bow via the same pvc pipe.
 

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The 1/2" PVC pipe connects the forward bilge to the aft bilge. Its fuel should leak from your tank it could be confined to the fuel compartment and/or drain into aft bilge. On my boat GW plugged it is plugged in aft compartment to prevent a fuel leak from getting into cabin and creating a explosion hazard. I would leave it there.

Another issue is fuel tanks should not not sit on the floor of the compartment. It should be raised up to prevent water from being trapped and creating crevice corrosion. Usually nitrile blocks 3M400'ed to tank.
 
Yeah the problem is I’m having to double up on 0.5” neoprene rubber strips just to get the tank sitting off the PVC pipe. I can still figure a way, cheers!
 
So I know I’ve kind of derailed this thread a little bit, but we just decided to double up on the 0.5” neoprene strips using 3M 4000 and it worked.

Now I’m curious what your opinions are on chocking the fore and aft of the tank. To secure the tank down we were planning on using some metal plumbing straps lined with neoprene underneath. We’d screw them into the stringers. But for the fore and aft gaps, I was thinking of screwing thick pieces of PVC into the bulkheads on either side of the tank to take up some of that gap. Then shimming it tightly with glued on neoprene strips.

What do you guys think about screwing a few screws into each bulkhead? We’d seal them up with 4000. In the photo you can see the gap in the front and rear of the tank.

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With plastic tank you don’t have a crevice corrosion problem but you did need to raise it up over the pipe.

On my tanks GW used HPDE blocks. Look at my tank replacement post. They are screwed into bulkhead. You can make them with a table saw. I used a torx head stainless screw in post as well.
 
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You're dealing with a plastic tank - that's different than what the OP is talking about. Plastic is easy - do whatever you want - you don't even need neoprene strips. Literally, you could just jam a piece of wood into the perimeter gap. Obviously you're going to make it more secure than that... but you get my point. PVC or glass L-channel can be used around the perimeter sides to help keep it secure... but you really only need a few pieces (say 3" long) per side. Keep in mind that plastic tanks can expand much more than aluminum so DO NOT make your securement too tight - if there's a blockage in the vent, they can literally start to look like a balloon!
 
BlueComet said:
Hookup,
Obviously you don't own this boat, but that's okay.

The boat isn't completely level. It never will be. I'd have to add 500 lbs to the bow and that's not going to happen, not fueling up with 3 people on the bow of the boat either. That's a hack, not a solution.

My "baffle" theory is probably wrong, there's likely no baffles. Doesn't change the symptoms.

Yes single engine, one's the vent, one's the pickup. The fill and vent hoses are correct. Had the boat repowered and re-transomed and they connected correctly too. It's the design of the tank, with the fill and vent co-located at the aft which is lowest part, it makes sense (liquid takes easiest path).

Got the drawing from Grady, attaching here since I'm not the only one looking for viable replacements on this forum or even THT. Hopefully that saves others time I spent, thats why this forum exists. The original drawing shows the vent toward the boat, not the stern, which makes sense. Fill, pickup and sender are aft, pickup should be at lowest point to maximize usable fuel capacity.

Short in short, this 52 gal tank is just wrong config for the boat. I can live with 52 gal or even smaller, but all that's useless when you can only get 20 gal in at most. The point is to get >20 gal in and not spill out when filling.

I've done a lot of homework on Moeller (and even Kracor) offerings to get into the length/width/height config with the vent and fill at opposite ends, and there just isn't anything out there that I've found. I was hoping someone else had a solution to save me the hours of research. Hopefully this will help someone else not waste same time I did.

Supposedly Patriot Marine in NJ has a stock tank that matches GW's drawing. That's cool but shipping isn't cheap in 2024, I'll report back on my findings. Going to look into Wilson Welding in Salisbury MA and see if they can maybe help too (and maybe save $700+ in shipping). Welding World has the larger tank already designed, but for $1500 + $800 shipping, that's not a great option.

Moral of this story, cheaping out in boating repair doesn't always work well (function or long-run cost). Sucks that GW didn't use a design that supports a "stock" poly tank, so AL is likely the solution for these boats.
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Hey, how did you make out with your tank?
FYI, I have a 1984 Overnighter 20 and just removed my tank. The dimensions match the tank in the PDF you attached except that the filler neck, vent neck and the pickup are all on the same end. I just got the boat and have not used it yet so I am not sure if there was a problem with it that way or not.
Did you ever find a better plastic tank? Or just get a new aluminum made? If so, what was the cost?
 
JDS535 said:
Hey, how did you make out with your tank?
FYI, I have a 1984 Overnighter 20 and just removed my tank. The dimensions match the tank in the PDF you attached except that the filler neck, vent neck and the pickup are all on the same end. I just got the boat and have not used it yet so I am not sure if there was a problem with it that way or not.
Did you ever find a better plastic tank? Or just get a new aluminum made? If so, what was the cost?
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Good luck. He never responded back with any type of response to his misinformed idea of the angle of his boat being the problem and/or never read the given suggestion/guidance on what the REAL issue could be. Doubtful he'll respond to your question :)

But, I think there was mention of pricing in the thread somewhere - read through it. Try looking in Moeller's catalog, as well.
 
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JeffN said:
Is the bow end of the tank shimmed up?
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on my boat the tank sits on 2 stringers and they are 3-4 inches higher in the bow than the stern. Its a 63" long tank. That makes it level with the deck cover.
 
I got my specs directly from GW. I'd go that route even if you have them now. Better safe than sorry.
 
Kent Fabrication in Pembroke MA makes tanks if you are south of Boston.
 
Fishtales said:
Kent Fabrication in Pembroke MA makes tanks if you are south of Boston.
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Thanks Fishtales, I was able to save my tank for re-use after all. It was painted, or coated before installation, and the foam was only used in 4 spots with the bottom clear to let water out. There was no outside corrosion on the tank at all but I bent the filler pipe pretty bad taking the old hose off. The hose was hard as a rock. I just bought a pipe expander kit today and it worked perfectly to bend the inlet back to perfectly round.
I only removed the tank to make sure the hull and stringers looked good, and they did. Really sucked removing it. I had to cut out about an inch of the flange/ floor to get the tank out but I'm glad I did. Plywood on the floor looked brand new and the stringers looked good too.
 
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