WATER TANKS - What to do, what to do?

[Billy Buck]

I am slowly working through the neglect of a stunning boat by a past owner. It's a little maddening, a lot heartbreaking, and a huge opportunity. Thanks for being the community helping me through that in part.

My next query is about water tanks. I had pics but can't find them. So I'll use my words.

The water tanks are under the settees, port and starboard. They are tied into an archaic and corroding copper system by gate valves. I have removed the hot water tank, pump, and all plumbing from the head back to where it tied into the main lines. On a great suggestion from Don Casey we are removing the sink in the head and turning it into a laundry chute. We are installing a hand pump faucet in the galley. We are refitting the boat with 'simple' as our guiding criteria.

The water tanks are disgusting. They haven't been opened or cleaned in years and are coated in what is likely algae (?) gone full 90 to black and for sure harmful. The access ports are tiny. The tanks are fibreglass and glassed into the hull and measure 60"(L) 26"(D) and 18" high at the inboard side and with the curve of the hull on the outboard side.

My wonder at the moment is whether to a) cut in bigger access ports, cut out the old valves and install new ones, clean out the tanks and install new water lines and use that simple system for grey water stuff in the galley or b) do I cut the built-ins out of the boat and install new water tanks in the same place?

A friend looked at them and said they would clean up okay and there is the added safety feature of water tight holds on both sides of the boat in the event of a holing. Seemed a severe observation but he's a Captain so I listen.

Thoughts CF?

[psk125]

KISS. It should be easier to clean what you have than to rip them out, install new, and then clean the new ones too. Cheaper as well.

[GILow]

Yes, cut bigger access ports and clean out wold be my approach.

Replace all the pipe work, it will never be clean and is probably a maintenance nightmare. PEX seems popular these days, I’m trying it myself.

I have just removed and recycled my old stainless steel water tanks and replaced them with the sort of built in tanks you already have, but have incorporated three large inspection ports on each tank so that I can easily reach every corner and surface of the tanks with my hand and a scourer.

Glad to hear someone else had the same thoughts I had about added integrity. My tanks straddle the water line, forward of midships where the beam is still increasing, which is a place more likely to hit a floating object like a shipping container. Mind you, the hull is over 30 mm thick at that point so it’s probably not an issue.

[coopec43]

Tanks for potable water should not be fiber glassed into the hull unless the tank is has a suitable non toxic coating. Without the coating styrene from the polyester leaches into the water.

West System does not recommend epoxy for water tanks.
https://www.epoxyworks.com/index.php...nk-guidelines/

Maybe you should cut large access ports so you can clean the internal walls of the tanks and coat them with a black water based bitumen suitable for potable water.

https://2ecffd01e1ab3e9383f0-07db7b9...af66fa699f.pdf

[GILow]

Originally Posted by coopec43

Tanks for potable water should not be fiber glassed into the hull unless the tank is has a suitable non toxic coating. Without the coating styrene from the polyester leaches into the water.

West System does not recommend epoxy for water tanks.
https://www.epoxyworks.com/index.php...nk-guidelines/

Maybe you should cut large access ports so you can clean the internal walls of the tanks and coat them with a black water based bitumen suitable for potable water.

https://2ecffd01e1ab3e9383f0-07db7b9...af66fa699f.pdf

Well, that’s one interpretation, it varies from country to country and West Systems are not the authority on water storage, they are merely a resin systems manufacturer. Their opinion should be viewed from this perspective.

However, in the interests of prudence, here in Australia, I use Sikalastic 560 for my tanks because it comes in white which makes it much easier to keep clean. Black would be a nightmare at hiding problems, possibly the worst colour you could use.

Sikalastic 560 is Australian/NZ Standard 4020 certified for water storage. Not sure where the OP resides, they’ll have similar standards and coatings available if needed.

And it comes in black if they’d like to hide any problems.

[coopec43]

" This is going to be a generalized statement because not all epoxies are created equal. Its important you research the brand of epoxy you are using and the chemicals/ingredients in it. However, for most epoxies that claim to be food safe, its critical that you understand that they can be food safe, if cured properly. Because it is ultimately up to the end user to mix, pour, and cure the epoxy, each application would have to be assessed individually to ensure it is properly cured in order to say that it is food safe.

https://epoxycountertopdiy.com/food-safe-epoxy/

How can a home builder ensure the epoxy is cured properly when he can't control the environment?
https://epoxycountertopdiy.com/food-safe-epoxy/

[Lepke]

Water and fuel tanks glassed into a fiberglass hull may supply some of the hull strength. I've been using West System Epoxy since about 1970 for water and fuel tanks. Cured they pose no problem. At one time I bought resin in 55 gallon drums. I've been drinking out of epoxy water tanks for probably half my adult life and I'm in my 70s. You can always use a tank coating approved for drinking water or fuel.
I never seen a growth in a water tank that didn't flush out once the organism was killed. Some day cut open a pipe in a house and see what the interior looks like. Or drain a hot water tank thru cloth.

[coopec43]

Originally Posted by Lepke

. You can always use a tank coating approved for drinking water or fuel.
I never seen a growth in a water tank that didn't flush out once the organism was killed. Some day cut open a pipe in a house and see what the interior looks like. Or drain a hot water tank thru cloth.

When using PVC for drinking water it needs to be "food grade" as it could leach lead into your drinking water. https://www.nationalpolyindustries.c...rinking-water/

If PVC pipes are exposed to sunlight algae will grow inside the pipe. Of course boat water tanks would not be exposed to UV radiation so coatings need not be black in color. Rainwater tanks are exposed to sunlight and therefore need a black coating inside the tank to stop leaching of harmful chemical and stop growth of algae.

[sailorboy1]

I would start be just bleaching and flushing the tanks. What you stand to lose by trying this first.

Btw algae is unlikely to hurt you. You have gor swimming in a lake i bet

[sanibel sailor]

Bleach is a wonder drug for algae and other organic crap.

[steamgoat]

Bigger access hole so you can clean them properly, pex plumbing and a foot pump for the galley. Hand pumps are a pain,try washing one hand while you pump with the other!

[Pete7]

Originally Posted by steamgoat

Bigger access hole so you can clean them properly, pex plumbing and a foot pump for the galley. Hand pumps are a pain,try washing one hand while you pump with the other!

Something like these would be nice, but at 5' long you will probably need two per tank and there might be a baffle in there to avoid. There is a clear lid type so you can see the contents which could be useful to check level and cleanliness in the future


https://www.force4.co.uk/whale-hende...cker-door.html

[Hartleyg]

I second keeping and cleaning those FBG tanks. If you use nasty chemicals (like bleach) make sure you have a way to dispose of it properly! An alternative might be to rent/borrow a steam cleaner - that should cut through any natural (algae) deposits without introducing chemicals into the mix.


It should also be possible to cut out & replace pieces of the tanks (such as where there are fittings) if necessary - be sure you use a food-safe coating on the inside, of course.



Hartley
S/V Atsa

[glenn.225]

Good advice above. I too would keep, make larger access holes and clean tanks.

For your pex plumbing I would use the SS clamp rings as they are secure, easy to install, you only need one (not expensive) tool and they easy to replace if you screw up or want to change lay out.

I have used the these types of clamp rings for plumbing and other automotive/boat uses, anywhere a hose has to be fastened.

Super easy to plumb in any system with these air, oil, fuel or water I have used them on all these systems. Its a handy tool for the DYI'er like myself just source a selection of various size rings and you can fasten any hose quickly and securely first and every time. Also they don't back off like hose clamps

Almost every building supplier will carry 1/2 and 3/4 rings, fittings and tool. You can use brass or ploy fittings, I use brass mostly. Auto supplies will carry larger size ones, I've used up 4 inch ones meant for CV joint boots with the same tool.

Here is video of one brand but there are several available. This tool incorporates a cutter but it is not necessary as if you clamp tight and twist back and forth the ring will break easy enough.

https://www.youtube.com/watch?v=Ltu1RdArHAM

[MJH]

Originally Posted by Billy Buck

I am slowly working through the neglect of a stunning boat by a past owner. It's a little maddening, a lot heartbreaking, and a huge opportunity. Thanks for being the community helping me through that in part.

My next query is about water tanks. I had pics but can't find them. So I'll use my words.

The water tanks are under the settees, port and starboard. They are tied into an archaic and corroding copper system by gate valves. I have removed the hot water tank, pump, and all plumbing from the head back to where it tied into the main lines. On a great suggestion from Don Casey we are removing the sink in the head and turning it into a laundry chute. We are installing a hand pump faucet in the galley. We are refitting the boat with 'simple' as our guiding criteria.

The water tanks are disgusting. They haven't been opened or cleaned in years and are coated in what is likely algae (?) gone full 90 to black and for sure harmful. The access ports are tiny. The tanks are fibreglass and glassed into the hull and measure 60"(L) 26"(D) and 18" high at the inboard side and with the curve of the hull on the outboard side.

My wonder at the moment is whether to a) cut in bigger access ports, cut out the old valves and install new ones, clean out the tanks and install new water lines and use that simple system for grey water stuff in the galley or b) do I cut the built-ins out of the boat and install new water tanks in the same place?

A friend looked at them and said they would clean up okay and there is the added safety feature of water tight holds on both sides of the boat in the event of a holing. Seemed a severe observation but he's a Captain so I listen.

Thoughts CF?

With simple as your "guiding criteria" I would clean the tanks and replace all the copper plumbing and gate valves. After you have convinced yourself that the tanks are clean I would have the water lab tested (not expensive) to insure it truly meets all health concerns. The test results should dictate where you go from there.

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