Water tanks s/steel /aluminum or ?

[delcrest]

Hi, have to install two new water tanks, nothing off the shelf seems to fit, whats the most popular construction material for this. Thank you in advance for your comments

[Calif.Ted]

Have you checked Ronco plastics ?
Ronco Plastics - Marine Water Tanks, RV Water Tank, Auto Detail Tanks, Water Tanks

[UNCIVILIZED]

Rotomolded Polyethelyne (sp?). They're plastic tanks which literally come in 1,001 sizes & shapes, so that finding ones which are a custom fit isn't tough. Plus they can in fact custom make them as well, at fairly low cost. And one of their big perks is that you can have whatever fittings you like put into the tanks where ever you like.
Also, they don't rust, are light weight, inexpensive, & it's easy to see how much fluids are in them since they're translucent.

[Cheechako]

Don't use aluminum. I had alum access covers on water tanks once, you don't want to know what the white creamy muck that accumulates on alum water tanks looks like!

[Stumble]

In order of preference... Plastic, plastic, plastic, then plastic, and finally titanium. I HATE metal water or fuel tanks. It's a corrosion problem waiting to happen. They can last for years, or you can wind up replacing them in five, and there is absolutely nothing you can do to effect which it is. It's all down to voodoo (yes I really believe this).

It's like being hit by lightning. On guy replaces his watch battery and the surge protector and is all good, the boat next door blew three the hulls out and is replacing his boat.

[er9]

Originally Posted by Cheechako

Don't use aluminum. I had alum access covers on water tanks once, you don't want to know what the white creamy muck that accumulates on alum water tanks looks like!

i agree with this. i just opened up my 35 year old aluminum water tanks to take a look inside. basically most of the inside of the tank was a gooey white muck of dissolved aluminum. i dont know if its harmfull to drink from corroded aluminum tanks but it does make the water taste metallic. i would rather not take the chance.

personally i'm going to replace mine with stainless steel and make sure to have a reasonably large access cover on the top so i can get inside and clean them once in a while.

[HopCar]

Not Aluminum! That stuff that Cheechako mentioned said disgusting
Ronco has about 500 different sizes and shapes of good plastic tanks. Don't forget you can turn them any way you want and Ronco will install the fittings where ever you want.
Make one of them work even if you have to give up some capacity.

[delcrest]

Thank you for the replies, looks like s/steel as I am currently in south Africa and there is not much choice with off the shelf available

[a64pilot]

I don't think the milky substance is Aluminum Oxide, that stuff is hard like diamonds, they use it in sandpaper I believe. I'd bet it is what we call down South Lime, or calcium carbonate that has precipitated out of hard water. Same stuff you see on kitchen sinks wherever the water comes from a limestone aquifer.

But plastic is preferable if for no other reason than you can "shock" the water with chlorine, something you may want to avoid with metal tanks.

[Cheechako]

Originally Posted by a64pilot

I don't think the milky substance is Aluminum Oxide, that stuff is hard like diamonds, they use it in sandpaper I believe. I'd bet it is what we call down South Lime, or calcium carbonate that has precipitated out of hard water. Same stuff you see on kitchen sinks wherever the water comes from a limestone aquifer.

But plastic is preferable if for no other reason than you can "shock" the water with chlorine, something you may want to avoid with metal tanks.

In my case it was only on the aluminum lids. The rest of the tank was not aluminum, so it's related to the Al in some way. It was hanging down in stalactite formations but soft and rubbery/gooey.

[Stumble]

Originally Posted by Cheechako

In my case it was only on the aluminum lids. The rest of the tank was not aluminum, so it's related to the Al in some way. It was hanging down in stalactite formations but soft and rubbery/gooey.

The hard white patina is aluminium oxide and yes is used in abrasives. The white goo is aluminium chloride.

I'll say it again metal water tanks are stupid. Unless you spring for titanium, in which case you are stupid because they are crazy expensive, though they don't suffer corrosion problems. Plastic all the way.

[bletso]

I have a 1979 globe with a dual 55 gal SS tank. 110 gal in all. They look pristine on the inside and the outside aren't bad either. Best of all never a plastic taste.

[laika]

I made my own integral tanks a few years back out of fiberglass and plywood baffles. You can source food-grade epoxy coatings and can install massive inspection ports to make regular cleaning an easy chore.

It's more work than sourcing a pre-made tank, but payoffs are worth considering. You end up adding strength to the hull, you keep every square inch of the hull accessible, and you maximize the usable space.

[tkeithlu]

Stumble, you really prefer plastic fuel tanks? Right with you on plastic water tanks - I wish my stainless steel one was plastic instead, but wouldn't a plastic fuel tank be a rather unwelcome addition to an engine room fire?

[Stumble]

Originally Posted by tkeithlu

Stumble, you really prefer plastic fuel tanks? Right with you on plastic water tanks - I wish my stainless steel one was plastic instead, but wouldn't a plastic fuel tank be a rather unwelcome addition to an engine room fire?

Six of one half dozen of the other. Plastic tanks can melt spilling fuel on the fire. Metal tanks heat up until the fuel flashes and causes an explosion destroying the boat in a fraction of a second.

The best option is to not install fuel tanks inside the engine room.

For water tanks... The plastic tank can leak and help put out the fire, metal tanks will heat up until the steam preassure excedes the ability of the tank to hold it, at which point high preassure steam is released in some random direction, likely cutting thru whatever is in its way.