Water Tank Replacement S2 9.2

[Inline Don]

Leaking Fresh Water Tank on my S2-9.2c (repairing)
First my personal recommendation is to replace the tank with a new aluminum 37 Gal. (same size as presently in S2 9.2 sailboats). This is the original tank from Fl. Marine Tank. Inc. dflori@fmtanks.com . Presently made in Henderson, N.C. (shipping). New quoted cost $425.00 + shipping, 4 week delivery time. The old aluminum tank is .090 aluminum while the new tank is manufactured out of 5052-H32 .125” aluminum. No baffles required. Aluminum can outlast the life of a boat if installed and maintained properly. Refer to article at www.yachtsurvey.com by David Pascoe. The S2 sailboat is well built, but they did not install the water tank properly, my tank bottom is flat on top of the deck below it and is also foamed in, which when wet causes “crevice corrosion” because of the lack of oxygen, on the aluminum surface, this is the area where I found most of the large holes (photo attached). I cleaned the tank with clorox and used to much, a no-no. I received tank replacement quotes from the following web sites.
www.lutherswelding.com Aluminum w/one baffle $700 made in MA.
www.plastic-mart.com Plastic Ronco #B414, 44gal. No baffles $325.00 + shipping
www.tank-depot.com Plastic Ronco #B414 $340.59 + shipping Fl. $152.92 www.Millerplastics.com Custom made 3/8” thick natural polypropylene $690.00 Made in Pa. + shipping
By the way I have done none of the above and this is why !
More photo's attached show that I opened the tank and installed four inspection and clean out ports. I am retired which allows me the time, also curious, cheap, always need a challenge, have the tools and try to keep in shape by Roller blading frequently. I had a welder look at my tank, he observed the many pin and larger holes and said he would save me money by not having him weld it. I than took the tank to local Line-X dealer, they do a spray-on composite made with Dupont Kevlar (photo attached) www.line-x.com. I also sealed the seams inside the tank with a NCS coating from ecosmartepoxysystems.com which you can apply either with a brush (thinned) or putty knife. Total cost for coatings, hatches, misc. about $325.00. Plus all my work and time $0.00. All of the above information is potable water safe. After searching many types of sealers I found most, if not all, are non-potable water approved, including Marine Tex, Gluvit and other epoxy. My reasoning 1. I could reinstall the tank in the same way it was originally 2. saving work in not adding hold down straps 3. keep the baffles which I believe are necessary (when full there is 309 lbs of water moving around in a enclosed area) 4. be able to clean it out again in the future and 5. no waiting time for a replacement, always in a hurry! I recommend replacement with a new tank simply because of the small difference between the cost of new tank and my repair approximately $170.00 plus new proper installation. The hardest part was removing the tank from the compartment it was stuck fast to bottom. Originally found only one hole which grew larger and another hundred pin holes appeared after a presser washing. This is why I opened the tank top. S2 owners, plan on replacing your tank if you haven't done so already.

 

[Inline Don]

Additional Photos' for above thread................

 

[BobM]

Note that Pascoe actually states: "Done right, aluminum tanks will last forever. Fuel tanks, that is, not water tanks. AL should not be used for water tanks, period."

 

[Inline Don]

Note that Pascoe actually states: "Done right, aluminum tanks will last forever. Fuel tanks, that is, not water tanks. AL should not be used for water tanks, period."

What I found with my water tank was that the large hole appeared at the area where it trapped moister from the outside of the tank. This is why I referred to this article as to how the lack of oxygen causes corrosion. If properly installed this tank may have lasted longer? There has certainly been a lot of research and articles written on this aluminum tank subject, which I certainly am not a expert. My only thoughts where to inform other S2 owners what I found and repairs I made. Cost, convenience and proper installation, is why I made my any personal suggestion. I added the web sites so that other interested owner can do their own research. As far as I can find aluminum is still used for water tanks?

 

[BobM]

Sorry Don...I wasn't particularly trying to pick on you or your statements, but I did find the statement I quoted on Pascoe's site too. His stuff is worth reading. I learned a lot about blister formation in particular.

Frankly I like your idea of coating the outside of the aluminum tank with something like truck bed liner material to protect it if aluminum is used. It might also be worth it for owners without leaks to pull and coat their tanks as a preventative measure.

However, it is best just to avoid aluminum altogether if you are replacing your tank entirely. Pascoe discusses methods of avoiding water contact / crevice corrosion by mounting an aluminum fuel tank by gluing a sheet of plastic to the bottom but given the similar cost and limited time for labor fit is just a better decision for me to use a plastic tank. Also, with my experience with my leaky fuel tank I guess I am more willing than some to brand aluminum as a questionable choice for a material of construction. Leaks formed both at the straps, where water likely was trapped against the bottom, but also at the welds at the low spot in the front of the tank at the seam. It is that location that water in the fuel likely pools in the inside of the tank.

 

[Inline Don]

It was interesting, one of the tank suppliers that I was in contact with, ask me how old my boat was, when I told him 25 years he indicated that boat owners should plan on replacing their water tank no matter what material it was made with, when the boats' age is about 25 years. I have no idea where he was coming from, but it did present questions in my mind. I have owned my S2 for 10 years. It has basically been maintenance free. This is the first major repair I have had, if you want to call it major? The original sails lasted until this year,(replaced). I have pumped out the fuel tank and also used additives. So far so good. I noticed how the fuel tank sets on the deck, it looks like they used neoprene straps between the aluminum and metal straps except at the bottom where they separated the straps and took the metal strap under the built up wood support and the neoprene on top of the wood between that and the aluminum tank.
The X-line coating is about 3/16" thick and I believe is guaranteed for more than 10 years. The aluminum tank had to primed first. This coating is very strong and cost me $250.00.