Water Bladder vs tank

[Snowpetrel]

Originally Posted by funjohnson

Good news. Our aluminum boat has integral tanks and trying to epoxy coat the inside has been horrible.... and not 100% sure it's all perfect. I think i'll give the Plastimo a shot.

Matt

Hi Matt, have a good hard look inside the tanks, I found a few nasty corrosion pockets inside mine this last slipping, they welded up nicely after using a dremel and a mini die grinder to clean the up. But two holes went right through to the bog! Tap water often contains chlorine that can corrode even marine aluminium.

[Matt Johnson]

Originally Posted by Snowpetrel

Hi Matt, have a good hard look inside the tanks, I found a few nasty corrosion pockets inside mine this last slipping, they welded up nicely after using a dremel and a mini die grinder to clean the up. But two holes went right through to the bog! Tap water often contains chlorine that can corrode even marine aluminium.

Thanks for the info.... I've spent around 20 hours with a die grinder and a wire wheel cleaning the nasties out of the tanks (three). They were previously coated on the inside, but with the failed coating, the aluminum corroded behind it. I had one hole into the ballast, but that's now welded. I wet sanded West System in the freshly ground aluminum (1 of 3), but it was a horrible mess and I don't want to do the others.

Matt

[Snowpetrel]

Ha Matt, sounds like a horrible job, mine fortunately had the tops completely removed, so access was good. And they were small. Prehaps the other could be used just for washing water, and have some magnesium anodes added? Part of me worries about corrosion under a damp bladder tank pressed up onto the hull, as much as internal corrosion on a alloy tank?

[Matt Johnson]

Originally Posted by Snowpetrel

Part of me worries about corrosion under a damp bladder tank pressed up onto the hull, as much as internal corrosion on a alloy tank?

It was bad. I did it before we had air conditioning, the interior temp was over 100 degrees, and I had to tent myself in plastic to reduce dust.... we were living aboard then too. It would be easier now, but I'm just not 100% sure everything is getting cleaned well since I can't sand blast in here. If the coating fails again, I don't want to ingest the alzheimer's causing white crap.

I'd need to lay foam down first to stop abrasion before I could add the flexible bladder. That may be even worse for condensation and corrosion.

Matt

[peghall]

Originally Posted by Rex Delay

Installed Plastimo bladders about 6 yrs ago. They were about $100 ea., plastic tanks about $1k ea. No issues so far, no taste, no leaks no issues. Even if I throw them out every 10 yrs, way cheaper than rigid plastic.

Have you actually compared the prices of rotomolded PE tanks from various sources? Or are you just assuming that because one mfr's tank is outrageously priced, they all are?

[Snowpetrel]

Originally Posted by funjohnson

I'd need to lay foam down first to stop abrasion before I could add the flexible bladder. That may be even worse for condensation and corrosion.

Matt

Prehaps some sort of rigid plastic with an air gap to let the space breathe would work? Then your foam and the bladder tank.



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[JPA Cate]

Originally Posted by nelsmay

I recently looked at a boat with flexible bladders inside nylon bags rather than a water tank. Could anyone provide some feed back on this? Their own experience. Long term serviceability, potential for leaks, general function?
Apparently the bags are just slightly smaller than the bladder's max capacity to prevent any sort of damage from overfilling.

Own experience: custom made hypalon bladders, lasted about 21 yrs. failed at seam.

Replacement PVC, tedlar lined from WM, the best we got out of them was 2 weeks. We had carpet underlayment under them, but they failed at the welds.

We then had custom s/s tanks made. Were careful to stand them off the hull for air circulation.. Lasted till we sold the boat, 11 yrs. later.

Water quality was excellent with all of them.


Opinion, I'd go with what Peggy said. Polyethylene tanks are good for water, do get ones with cleaning ports. Sometimes there's a lot of sediment in water you get after rain. Nice to be able to clean it out.
Ann

[Sun and Moon]

Originally Posted by peghall

Better yet, and not only a LOT easier, but prob'ly close the same price is top quality rotomolded PE tank from Ronco Plastics (no relation to the VegoMatic Ronco) Ronco Plastics Marine Catalog They make TOP quality thick-walled water and waste tanks for a very reasonable price and has more than 400 shapes and sizes, over 100 of which are non-rectangular, and they install fittings in the sizes and locations specified by the customer when they make the tank. There are several retailers--Plastics Mart is one--who sell Ronco tanks, but you can buy direct for a lot less. Be sure to specify "water" when you order it.

Thanks Peg, I'm looking at tanks for my boat, too. I think I'll follow your advice.

[HopCar]

I second Peggie. The Ronco rotomolded tanks are first rate and reasonably price. I got my two water tanks and my holding tank from them. They are more than 25 years old now and working fine.

If you want a flexible tank look at Aero Tech Laboratories (ATL). They make very high quality tanks. They were the favorite auxiliary fuel tank for drug smugglers back in the seventies and eighties. They also make tank liners to fix leaking rigid hard tanks. Bladder Tanks, Collapsible Pillow Tanks, Helium Recovery Bladders, and Frac Bladder Tanks for Fuels, Water and Chemicals

[Snowpetrel]

Turtle pac in ausssie make some pretty tough gear.

http://www.turtlepac.com/products/yacht-tanks.html

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