To Tank or to Tank?

[Boots and Socks]

Ya that about says it all. After 20+ years the SS water tank on our boat has desided to drain its self without permission or a pump. With this said I get to pull up the floor and get a new one down there, but what to use? We were planning on staying with Stainless Steal like the current tank, but some of the other sailers here say I should look at plastic. So I am putting it out to you all to see what people thoughts are.

[team karst]

I would look for an off the shelf HDPE tank that fits.

[peghall]

Metal water tanks that carry treated municipal water have an average lifespan of about 20 years, a bit less if you add a little bleach to each fill. So I agree that a plastic tank is best way to go.

Almost all off-the-shelf PE tanks have only 1/4" thick walls...all vertical walls would have to be externally supported to hold 55 gals of water or waste, both of which weigh 8.333lbs/gal, without flexing or bulging.

IMO Ronco Plastics is your best source. They make TOP quality thick-walled (50% thicker than most other mfrs) water and waste tanks for a very reasonable price and have more than 400 shapes and sizes, over 100 of which are non-rectangular, and they install fittings--including diptubes--in the sizes and locations specified by the customer when they make the tank. There are retailers who sell Ronco tanks, but Ronco sells direct for a much lower price...and they're great to work with.
Ronco Plastics marine Tanks Ronco Plastics tank drawings


--Peggie

[rslifkin]

Ronco makes good tanks. If they don't have one of a suitable shape and size, check with Trionic tank. I've bought from them and been happy. They also make tanks of the same caliber and wall thickness as Ronco.

[s/v Jedi]

If you plan to use the water for consumption then use stainless steel or fiberglass with specialized coating inside, no plastic.

Even if you plan to filter, check if your filter can take out everything that a plastic tank can seep out. As long as one can taste it, something comes out.

[JPA Cate]

For a boat that size, if he tank was designed to fit, it will quite possibly be better (less waste space) to replace with another s/s tank. It will help its longevity if you space it clear of the hull (can use timber or plywood for this, so it has air around it, and doesn't sweat: it will rust out quickly if it does.

We've had s/s and plastic, and never had a flavor from either. However, I would expect a charcoal filter in the drinking water would take care of it. We did use chlorine to treat water in both types of tank.

Ann

[s/v Jedi]

Originally Posted by JPA Cate

For a boat that size, if he tank was designed to fit, it will quite possibly be better (less waste space) to replace with another s/s tank. It will help its longevity if you space it clear of the hull (can use timber or plywood for this, so it has air around it, and doesn't sweat: it will rust out quickly if it does.

We've had s/s and plastic, and never had a flavor from either. However, I would expect a charcoal filter in the drinking water would take care of it. We did use chlorine to treat water in both types of tank.

Ann

I am afraid we live in a time where your health is not on the mind of those manufacturing and selling water tanks. You can not just “expect” you will be fine, you need to make sure. Like those “candle filters” so popular with offgrid living… there was no need for their independent test results… until someone paid to have it done and they failed big time.

Filters need official ratings and you must know what (incl. which chemicals) they are rated to block to levels safe for consumption. Many filters in use do not have those ratings.

I have done a lot of testing and the only time I can’t taste the chemicals coming from plastic is with a new polycarbonate bottle. When the bottle is a year old, I can taste it (and they have a due date printed on them).

My test is simple: take RO water, filter that through a NSF rated filter (like Seagull IV) then fill a stainless steel bottle, a glass bottle and the bottle (or tank) you test. Let it stand for 24 hours then do the taste test.

Most people can tell the difference between Coke from a plastic bottle or a glass bottle and this is why they still sell it in glass bottles. Not that it matter with Coke as it’s causing more deaths than anything…

The tricky thing is that not all chemicals can be tasted. You may filter water and find it tastes great but still has high contamination levels.

[rslifkin]

Originally Posted by s/v Jedi

Most people can tell the difference between Coke from a plastic bottle or a glass bottle and this is why they still sell it in glass bottles. Not that it matter with Coke as it’s causing more deaths than anything…

That's for different reasons. At least around here, the glass bottle Coke is made with real sugar, while the plastic bottle stuff uses corn syrup.

[s/v Jedi]

Originally Posted by rslifkin

That's for different reasons. At least around here, the glass bottle Coke is made with real sugar, while the plastic bottle stuff uses corn syrup.

There’s places in the Caribbean where you can buy 1.5 liter bottles of Coke with either red or white tops… red with genetically modified corn syrup and white with real sugar

Anyway, I taste the PET plastic bottles.

[peghall]

Plastic water tanks must be cured differently from waste tanks...a good quality tank that's specified to be a water tank will not "seep out" anything.


--Peggie

[s/v Jedi]

Originally Posted by peghall

Plastic water tanks must be cured differently from waste tanks...a good quality tank that's specified to be a water tank will not "seep out" anything.

--Peggie

The good quality water tanks, even though they don’t have food grade markings I think, still seep out chemicals. It is the amount and kind of chemicals that governments deem not dangerous to our health, but with the track record of having to come back from it over and over (we came from safely rated lead water pipes) you can bet any chemicals are bad.

Stainless steel is far superior. Even water from cement lined cisterns is better than from plastic imo..

Some searching online will show glass, ceramic and stainless steel being the inherently safe options.
Plastics that are rated safe, become unsafe after heating, damage like a scratch and calendar aging.

[sailingharry]

Not everyone agrees that stainless is inherently safe. A new stainless steel steering wheel comes with a California Proposition 65 warning on it. The one that says it contains chemicals known to the state of California to cause cancer. In the case of stainless steel, that's the chromium that makes it stainless.

I don't think it means anything, but I find it humorous.

[Searles]

My Bob Perry 48 ft cutter 1982 ,had black iron fuel ,diesel tank and s/s fresh water and Grey water tanks all has minor leaks ,removed the lot and built in new tanks ,vinalester finished with west epoxy lined with food grade tank liner resin, the tanks also form a double bottom where they are fitted ,considerly increase the volume for the same area ,not an easy job but well worth the effort ,f/w charcoal filters all good .⛵️⚓️

[s/v Jedi]

Originally Posted by Searles

My Bob Perry 48 ft cutter 1982 ,had black iron fuel ,diesel tank and s/s fresh water and Grey water tanks all has minor leaks ,removed the lot and built in new tanks ,vinalester finished with west epoxy lined with food grade tank liner resin, the tanks also form a double bottom where they are fitted ,considerly increase the volume for the same area ,not an easy job but well worth the effort ,f/w charcoal filters all good .⛵️⚓️

Yes, that coating will actually stop out gassing after a number of years but what comes out is caught by the carbon block filter. I have this for water tanks as well.

[rslifkin]

My water tank is also fiberglass/epoxy lined with a potable water safe epoxy. Most stuff that will come from a plastic or fiberglass tank can be caught by carbon filters provided the filters are big enough (relative to your water flow rate) to ensure adequate contact time.