Leaking Fresh Water Tank

[DanW]

I have an '88 340 Sundancer with a leaking fresh water tank. I think everyone with this era boat has had to deal with this! The original one was replaced in 2010 by the previous owner. They had new metal one custom made. I would like to replace it with a plastic tank. There are many threads on here that I searched through and found references to Ronco Plastics and Todd Marine Tank. Any other suggestions? Has anyone replaced one before in a late '80s 340 and would like to suggest what they installed? Does anyone make custom plastic tanks? Would anyone recommend staying with a metal tank? If so, any recommendations on a maker?

I want to get back on the water soon! But my cabin is all torn apart while we search for a water tank.

Thanks,
Dan

 

[NorCal Boater]

I have an '88 340 Sundancer with a leaking fresh water tank. I think everyone with this era boat has had to deal with this! The original one was replaced in 2010 by the previous owner. They had new metal one custom made. I would like to replace it with a plastic tank. There are many threads on here that I searched through and found references to Ronco Plastics and Todd Marine Tank. Any other suggestions? Has anyone replaced one before in a late '80s 340 and would like to suggest what they installed? Does anyone make custom plastic tanks? Would anyone recommend staying with a metal tank? If so, any recommendations on a maker?

I want to get back on the water soon! But my cabin is all torn apart while we search for a water tank.

Thanks,
Dan

Hi Dan....

Is the stainless one not repairable? Do you want to go plastic for the weight savings? I'm not sure how easy it's going to be to find a poly water tank specifically made for a 30 year old boat. It sounds like you are going about it the right way though. Keep searching....

Shawn

 

[hottoddie]

When you say "metal" do you mean stainless or galvanized? If stainless and if it was installed properly then why replace it?

 

[BigPhatButt]

Lol, our cabin is in the same state right now.... Just got the tank out yesterday on our '87 390 EC.... The original 101 gallon aluminum tank..
We've looked at many suppliers... Mostly roto-formed 3\8" plastic... Most will manufacture any size to your specs...Sullivan plastics does custom welded units.

 

[Lazy Daze]

The tank is barely 8 years old. If it was made and installed properly, it should NOT be leaking. Are you positive you have a tank leak and not a leak from somewhere else (rain)?

Is it a SS or aluminum tank? Both SHOULD be able to be readily fixed. Then, figure out what cause it to fail (possibly a bad weld or bad install) and fix that. You should be good for at least 30 years.

 

[DanW]

My mechanic pulled it out so I don’t know the type of metal. Looks stainless from the pictures. But we did confirm the tank was leaking. He could see the corrosion and sent me pictures of it.

I agree it shouldn’t have failed that quick but I don’t know the cause. It might be repairable. I haven’t asked mostly because I thought a plastic one would last longer and would be better to just replace it now while the cabin is pulled apart.

I was able to find what looks like an exact replacement from Ronco Plastics for about $500. Any reason I should repair what’s in there versus replacing with the plastic one?

Dan

 

[hottoddie]

Once a tank leaks I would not trust a repair no matter what material it's made from. Go for the plastic tank and make sure it's properly supported and good fittings and hoses.

 

[Lazy Daze]

My mechanic pulled it out so I don’t know the type of metal. Looks stainless from the pictures. But we did confirm the tank was leaking. He could see the corrosion and sent me pictures of it.

I agree it shouldn’t have failed that quick but I don’t know the cause. It might be repairable. I haven’t asked mostly because I thought a plastic one would last longer and would be better to just replace it now while the cabin is pulled apart.

I was able to find what looks like an exact replacement from Ronco Plastics for about $500. Any reason I should repair what’s in there versus replacing with the plastic one?

Dan

I wouldn't condemn the existing tank till I knew what was going on -- why it is leaking, where it is leaking from, how much corrosion there is, etc. Get facts, then decide. Post the pictures?

 

[DanW]

Here are pics, but not sure you can tell from that. I can’t tell what I’m looking st but you may know more. I’m waiting for additional info from my mechanic.

 

[Lazy Daze]

Yeah, it's hard to tell from the pictures. In the first two pictures, the bottom appears to be pretty smooth and intact. I can see what I think are holes in the third picture, but I'm not sure - and can't really tell where they are and the extent of it.

 

[BigPhatButt]

Same as ours.... Aluminum. The corrosion is worse on the inside of ours....and the tank is also cracked at both baffle welds. Scrap aluminum for sure... Plastic should last long past our time

 

[DanW]

Yeah, I think since everything is pulled apart to get to this tank and I’ve found an identical plastic replacement, I’ll go that route.

Thanks for all the input!

Dan

 

[ttmott]

Put between the tank and the hull those click together rubber floor drainage mats so any water will drain away from the tank and the mats will cushion the tank against the uneven hull surface. Also never fill the tanks completely full; I always stop filling then the full light starts to flash. When they are full to when water runs from the vent the tank top is bulging; this puts a lot stress on the tank corners where most cracks appear.
This is the stuff I used when I replaced the tank in the 400DA - https://www.homedepot.com/p/Multy-H...ber-Drainage-Floor-8-Pack-MT5100108/205856497

 

[DanW]

Thanks. I’ll do that.

 

[Lazy Daze]

For general knowledge to anyone else reading this... ONLY use those mats if using a plastic tank. DO NOT use them with a metal tank - they will hold moisture and cause corrosion. Plastic tanks conform well to slightly irregular surfaces so the mat really isn't "necessary", but there's no problem with using them, either.

 

[northern]

Installation questions
Did you have to cut the floor in the boat
If yes how do you plan on repairing the area
Will the patch effect the boat integrity
I had to replace the water tank on our 28 footer (First boat). I had to cut the original tank up to get it out and to replace it I used two smaller tanks as I could fit them in the same place as the original tank.

 

[DanW]

Northern, I got lucky. The tank is below the steps and under a raised portion of the cabin. So, although a lot had to be removed to get to it (table, convertible seats, stairs, divider, and floor), nothing was destroyed. It can all be put back together. I also found a direct replacement tank for my boat. Same shape and dimensions (45 gallons instead of 50 though). I can’t believe they carry an exact replacement for a 30 year old boat. When I found out it was leaking, I thought i was going to have to go your route. Glad I didn’t.

Dan

 

[Ricochet]

DanW
I am in the process of replacing my tank also, it looks like a lot of that going on this winter, I bought a custom tank form Dura Weld out of Florida, very happy with the tank so far, they installed 3 baffles also, I am installing it on some 1/4" starboard strips at about 10" on center than putting 1/8'' neoprene gasket material on top of that to help keep it from moving, also using 1/4"" 2x2 PVC angle on the ends and side to keep it in place.

 

[Snapon24]

Northern, I got lucky. The tank is below the steps and under a raised portion of the cabin. So, although a lot had to be removed to get to it (table, convertible seats, stairs, divider, and floor), nothing was destroyed. It can all be put back together. I also found a direct replacement tank for my boat. Same shape and dimensions (45 gallons instead of 50 though). I can’t believe they carry an exact replacement for a 30 year old boat. When I found out it was leaking, I thought i was going to have to go your route. Glad I didn’t.

Dan

Where did you find a direct replacement tank? Im looking for a poly replacement right now for my 340. Thanks

 

[ocgrant]

I went through this in my 91 Princess. It was an aluminum tank and it just corroided away down low. I replaced it with a custom plastic tank made locally in Orange County CA, don't remember the maker. It was a lot of work but in the end was worth it. Take take your time and do it right... bracing is the key to lasting as when full there is a lot of weight tere to move aruond in rough seas. Don't need it loose banging around.