1979 170 fuel tank replacement

[kraw2]

At the least get it epoxy coated then if it does get wet there will be no problem. I had the strips and 5200 but after applying the coating I used foam and glassed it in. It will be good for many years and will probably outlast the boat.

[gran398]

Make sure the strips are not starboard. 5200 will not adhere to polyethylene.

[alandry100]

Some pictures of the tank.





Some of the coffin, still need to clean up - the fuel and vent lines are foamed in. I started cutting away foam from behind the pie plate near the fuel fill. I think this will be the trickiest part, any hints about how to get the lines free would be appreciated. Also the wood is soft and I think rotten around the coffin lid pie plate peep hole? I guess I will have to learn how to fiberglass.

[Capt. Bob]

the fuel and vent lines are foamed in. I started cutting away foam from behind the pie plate near the fuel fill. I think this will be the trickiest part, any hints about how to get the lines free would be appreciated.

Here's a start.
http://classicaquasport.com/smf/index.php?topic=6789.msg49146#msg49146

Good luck. <!-- s:thumleft: --><!-- s:thumleft: -->

[alandry100]

Thanks for those links. I use the search often and every time I do it "ignores" tank and fuel even thought I use the + before.

I hope the removal of the lines is not as problematic as those - yipes.

Does anyone know if  there is a genuindealz.com equivalent for fuel lines...?

[kraw2]

I have a new WEMA 5.5" sending unit if you are interested.

[HeavyDinSC]

I'm going through the same process that alandry is with the tank on my 1986 Aquasport 170. Mine looked similar when I exhumed it, but I did have a bunch of pin sized holes (and a few larger) from corrosion. Before I get the new tank installed, I'm thinking about adding a one-way drain plug at the aft end of the tank basin (what he calls the coffin) so that water can exit, but not enter. Any thoughts on this solution?

[gran398]

I'm going through the same process that alandry is with the tank on my 1986 Aquasport 170. Mine looked similar when I exhumed it, but I did have a bunch of pin sized holes (and a few larger) from corrosion. Before I get the new tank installed, I'm thinking about adding a one-way drain plug at the aft end of the tank basin (what he calls the coffin) so that water can exit, but not enter. Any thoughts on this solution?

That is an excellent idea. Boat goes on plane, water goes out.

[alandry100]

Mine has a small hole in the center aft - this seems to have kept it mostly dry.

[HeavyDinSC]

Alandry,
That hole in the aft center of the coffin works well until the bilge gets too full, which might happen due to rain, a failed bilge pump, or when someone forgets to put the hull drainage plug in before launching. That's why I was thinking of adding a one-way drainage valve there.

[alandry100]

HDSC -That is a good idea - if you find a good valve please post.

[gran398]

Best to you both for good thinking. By golly, we don't need water going anywhere we can help.

If the auto bilge pump fails...operator error, the float switch failed. No need to encumber the fuel cell with an unnecessary extraneous valve. Those one way transom drain flapper valves work off of pressure from the high side....heavy pressure.

That won't occur in the coffin.

Drill a nice drain hole in the aft bulkhead of the coffin...let it seep naturally.

That's all you need, you're golden.

[Curious]

I pulled the tank out of my boat and plan to replace this winter.  In the meantime I was worried about water getting into the empty tank coffin so I drilled a hole in the rear base of the coffin and I plug it with a regular 1 1/4 transom screw type expansion plug.  I can access it from the deck hatch I have in the stern just forward of the motor.  So every once in a while I can unscrew and remove to see if any water got in there.  Something to think about but just make sure you have an inch or so at the rear of the tank so the plug doesn't bump into the tank and I don't know if this would work if you are going the foam route.
Dan

[seabob4]

The REAL key with fuel tank compartments and installations is to keep water out of the compartment.  When I install a tank hatch, I do it in a similar fashion to installing a Bomar hatch.  A seriously heavy bead of silicone goes down on the hatch receiver (the little "shelf" all around the opening that the hatch rests on) such that when I screw it down, I get GOOD squeeze out all around the hatch.  The once it's screwed down, fill the seams up to the deck with silicone, smooth it out, no water is going to be able to get in that compartment now, at least not through the hatch seams.

For the inspection pies over the fill/vent necks and over the pick-up/sender area, you want to use a good quality pie, not a cheapie, ones that have a serious O-ring to seal the center cap.  Bed these in the same manner as the tank hatch, such that when you screw them down, you get squeeze out all the way around.  These 2 operations should ensure that no water is going to get into the tank compartment via the topsides...but...

It seems that water somehow, in it's wicked and mysterious way, gets into the compartment.  So, the key here is that any water that gets in there doesn't have a chance to rest and pool against the tank.  That is the biggest bane to fuel tanks.  In the "business", we used neoprene rubber, adhesive backed, that we apply length-wise to the bottom of the tank.  Easy to install.  Length-wise allows any water that enters the compartment to drain aft without any chance of it being able to pool against the tank.  Regardless of the material you use, you must do this...the tank must not rest on the floor of the compartment.

Install as described above and you'll never have any problems.

[kraw2]

That's why I foamed mine in, epoxy coated, and waterproofed. I also use solid cover plates. No way for water to get in.