A38 water tank replacement

[Sam Stone]

HI All,

I think I need to replace my water tanks as one of them has sprung a leak. The main indication is water in the bilge while filling the tanks, I think the leak is probably a failed weld at or near the top. After filling the tanks about 4g or so accumulates the main bilge then stops. My initial thought is to pull the tanks and get copies fabricated. The originals did last almost 50 years after all. This looks like a huge and expensive job. Has anyone here done this before? Any tips or advice?

Thanks,

Sam

S/V Ligaya (#33)

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[Chris]

Hi Sam,

I was the guy that installed your tanks in the first place so I feel your pain. The tank size is such that they were installed before the cabin sole and interior. Some time in '75 or '76 the tank size was increased from two tanks of about 35 gal each to the larger tanks of 65 and 40 gals. The earliest factory finished boats had aluminum fuel tanks under the sole and SS water tanks under the settees. This would have been hulls 9, 11 and 12. When the fiberglass tank under the engine was created this opened up the space under the settees. 

Do you know which tank is leaking? A portable sewer camera might help locate it. If it can be accessed without too much wood butchery repair might be an option.

Otherwis, unless you want to gut the interior the only way the tanks will come out is in pieces. Cutting the cabin sole out between the settees would make this much easier but would still be a job in itself. There are plywood bulkheads beneath the sole between the tanks and on either end that the tanks are bolted to. If the center bulkhead is cut out you may be able to get better access to the aft tank. The area under the tanks slopes aft so the aft tank might not be able to slide forward as it is quite a bit deeper. An angle grinder with a cutting wheel is probably the easiest method to cut the tanks but is a miserable job and messy. One the tanks are removed you can decide what to replace them with. Bladder tanks are a simple solution but care must be taken against chafe and they must be well secured. Multiple smaller tanks of SS or HDPE are another option. If  you chose to have new tanks fabricated make full sized mock-ups to make sure they will fit through the main hatch and can fit into the space without interference. 

Just out of curiosity, do you know who your boat's original owner was or what her name was?

 Chris Welton

Former AYC engine and systems guy

[Shaun Sims]

When we first purchased our Alajuela 33, ‘Mico’ we discovered a small leak in the forward tank.

After drying the tanks out, we did a quick acid wash and inspected the seams with a sewer camera and discovered some small pin prick holes in a couple of corners.

Apart from that, the rest of both tanks seemed in pretty good shape.

I was not confident I could get a bladder down into the existing tanks. Nor, too keen on removing the cabin sole and replacing the tanks completely.

Our compromise was to cut larger inspection holes in the top of each tank to enable better access. We then fabricated new lids which could be threaded into the top of each tank with a rubber seal between the two.

The wider access holes allowed us to reach inside and run a thick layer of potable water-compatable sikaflex along all seams and then, using a fabricated ‘corner’ spatular, press and fare the compound deep into each corner.

For the next 7 to 8 years we sailed Mico without seeing a single drop of leaking tank water and to the best of my knowledge, her new owner has not encountered any either.

Of course, had we discovered any holes or failure in the tank walls, we’d have had to replace them completely - fortunately that was not the case but nothing lasts forever so at some point - total replacement is going to be required.

The big consolation for any Alajuela owner is they are superbly designed and exceptionally well made and with good care, they’ll outlive us all!

While we have now crossed over to the dark side and cruise a catamaran, there’s still no better vessel I’d rather be at sea in heavy weather than an Alajuela.

Fair winds.

Shaun

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