Fresh water storage...would this work?

I have two approximately 200 gallon aluminum fresh water tanks on Belladonna so 400 gallons. One has a leak, and considering they are 44 years old, who knows about the other. They look perfect on the outside, but...

Ideally fixing them would be great. They only have small access panels maybe 5 inches across, so getting into them isn't possible. I cant get to them from above without ripping up the floor above, and they aren't removable in one piece. I MIGHT be able to jack them up a few inches to be able to weld in patches, but concerned I might not be able to get to the areas that need repair, and I might just spend days of work only to be frustrated. I could potentially cut open the sides, repair from inside, then weld them back up again........maybe??? lol

Of course there is the possible link between aluminum and Alzheimer's to think of too. lol

My thought had been to cut the tanks out, maybe just leaving the bottom panel of each tank as a handy platform. IF I replaced them with plastic tanks (yes there are health concerns with plastic too...lol...can you tell I am in the medical field?) I have two separate questions about the replacement.

1) How much fresh water do I need?

I am considering living aboard, which means during winter months you have to unroll a hose to fill the tanks from a distant source, empty the hose and store it. Not fun if the weather sucks. Which means I might want lots of water storage........but........

Storing lots of water on board means the below decks compartment needs to be kept warm enough to prevent freezing, and if I recall correctly it takes a lot more energy to keep water warm than air, so am I creating an energy sink by keeping too much water on board?

2) Depending on how much water I end up needing, I need tanks (if I don't repair what I have). Has anyone thought about using the 55 gallon food barrels I see available on craigslist all the time for $10-$20 each for water storage? They are very heavily made and I THINK could be interconnected with bulkhead fittings.

Just wondering as I'm always trying to think outside the box, and sometimes the ideas are great, while other times..............................lol

In the picture they are the far set of tanks and hard to see, but the pic gives you an idea of the space involved. The closer tanks are 300 gallon fuel tanks each which are 6 ft long and 33" tall.

Fresh water tanks are easier to repair and not as concerning as diesel. If they do not leak to bad your could install a sump pump and divert the water to the sump. Some boats drain the grey water, shower, into a sump that is pump over the side. That is the way the Eagle was.

If you want to try and repair being fresh water and aluminum you might be able to repair with out welding if you rough/scratch up the area using epoxy, liquid weld? If it leaks again the water drains into the bilge, and you try again.

Are the tanks connect to the zinc loop as aluminum does not have a very high galvanic rating in some industries is use as a sacrificial metal. Aluminum does not rust but it does corrode into white dust. So try some thing and if they do not work then we can talk about removing and options. Being the Eagle is 35 years I have some thoughts.


As for how much and how long, does the marina water freeze and if so how thick. In the PNW the water temp in the winter is about 50 degrees, and the Everett marina does freeze over for weeks at a time, but no cold enough to freeze the bilge. So how cold is the water the boat is in and thick does the water freeze.

At least you have access to water. In the PNW many marinas shut the water off for weeks at a time. The Eagle holds 400 gallons which will last about 4 weeks but we have to real conserve water, and supplement drinking water, no laundry, very short showers, one sink of dishes per week, and not wasting of water. Being alive aboard you make due what is availible.

IF you can drop in a bladder it would be the easiest solution.

Custom to your measurements only takes about 2 weeks.

LOTS of water is not required for good winter living , two tanks , so when one runs out your not stuck is the solution.

Then the refill can be done in a day or two, instead of O'Dark 30 when the pump began to scream.

Remember there will be 10 or 20 G or more in the hot water system , and most diaphram yacht/RV pumps will push enough air to move it.

Well Phil, it varies here in the upper Chesapeake/C&D canal. Some years like the past 2 years almost nothing freezes. Other years it can freeze over...to what depth I'm not sure. The hull is aluminum, so whatever it is outside, its the same inside I'm sure. lol. That means I don't just have water temp to deal with as there is plenty of hull above the waterline, and if its 12 degrees outside with the wind blowing...it might be hard to keep 400 gallons of water above freezing. I'm just not sure yet, but its a concern.

The previous owner tried to use gobs of 5200 for repair, but he said it still leaks a bit. I believe the other tank isn't leaking yet, so I may separate them.

The marina here does shut off water to the docks in the winter. We have to run a hose from the building. Not the end of the world.

FF.....hmmmm.....a bladder might be a good idea. Can you share who makes them? I might be able to cut the side of the tank off, insert a bladder, then put the side of the tank back on with brackets.

Oh.........I don't have a sump. All grey water on Belladonna is above the waterline, so it just drains overboard. The leakage from the freshwater tank isn't awful at this point and it just leaks into the bilge where it can get pumped out, but I don't like ignoring things that should be repaired.

As to how much fresh water do you need, that's a bit of a how long is a piece of string question. Do you live aboard? Do you take long cruises? Is where you go pretty lean on fresh water (like the islands here in the summer)?

Our boat has its original tanks, two 75 gallon stainless tanks in the lazarette. We use the water from them for everything--- drinking, showers, dishes, etc. We use the boat year round, often staying on it for a weekend if we can't or don't want to go out. So the water gets cycled through at a reasonable clip. We keep the tanks topped off because with them full the boat trims properly for the deck drains which is important in the PNW with its 24/7/365 rain.

For our longer cruises, two or three weeks, if we have guests--- never more than two--- we will top off the tanks perhaps twice. If it's just us we can easily do the whole two or three weeks on 150 gallons although we usually top off once during the cruise.

We used to winterize the fresh water system, putting in the "pink" stuff and running it through all the lines. After a few years of doing this and then dealing with the taste and smell of the water all summer even after flushing the system several times we stopped the practice altogether. We leave the tanks full during the winter. It rarely gets below freezing here except at night. But as long as the temperature get above freezing during the day we don't worry about it.

We keep two electric oil heaters in the boat during the winter set to their lowest heat range. One in the engine room and one in the aft cabin. The water tanks are right up against the aft cabin bulkhead and there are some small holes and passages between the cabin and the lazarette. So some heat probably gets to the tanks.

To be safe we keep a pillbox heater in the lazarette during the winter. If the forecast calls for several days in a row of below freezing weather or we think there is a possibility of this we will turn on the pillbox heater which puts out about as much heat as a 60 watt lightbulb.

In the ten or eleven years we've been doing this we've never had any freezing problems at all even when it's been cold enough for several days to put a layer of ice on the water in the marina. We keep a bottle of water-- the plastic bottle you buy at 7-11, etc.--- lying on top of one of the water tanks as an "indicator." In the almost 15 years we've had the boat it has never frozen.

Hey Marin, thanks for the reply! Yes, I'm thinking seriously about living aboard. Of course I have a lot of hull above waterline, and its all aluminum. Scratching my head and wondering how much that changes things from those of you folks with 'glass boats. I COULD just keep the one tank that is good so far on the starboard side while adding a smaller 2nd tank as a backup. 1500 lbs of water on one side may not make that much difference to a 60,000 lb boat for now. I like FF's idea of a bladder though for the bad tank. I need to find out more about that.

I just made another post about heating with a pellet stove...if I go ahead with that it may not make much difference how much water I have on board anyway.

Most tanks have baffles welded in place. If you cut the baffles out you will have to do a perfect job of virtually polishing the old welds and cut off baffle bits because the slightest imperfection will create a wear point that will very quickly poke a hole in that nice new bladder and you will be right back where you started.

The labor to remove the baffles to the standard you need to install a bladder is probably more than that to remove the old tank in pieces and replace it with multiple plastic tanks manifolded together for the capacity you desire.

Well you could make a sump. Just have to take out of couple of inches and epoxy/fiberglass and a small bilge pump with a float. The sump on the Eagle is 6” X 6” and 3” deep.

The temps in Everett get down in the low 20 and teens with wind chill factor, but the surrounding water is a huge heat/cold sink, which should keep the are below the bilge from not freezing and then if you he above the water line that will help also.

Calking even 5200 does not have strength. The strength is being under pressure not topical application. I would remove the 5200, grind down and use Epoxy with #4 additive mix into a paste or liquid weld which is sort of a epoxy. I would give some things a try before even thinking about bladders, and removal.

So are the tanks zinc protected. Zinc is rate 3 and aluminum depending on kind rates 7 to 15 buts still lower than mild steel. So what ever you use make sure the galvanic rating is below zinc.

At least you have water during the cold winter temps.

Interesting thought Rick....there is a small access on the side of each tank and I could remove to check for baffles.

Phil, can you explain how the sump would help me? The tank is leaking from one of the back corners, not easily accessible and then running down the support and into the bilge. So I'm not sure how I would be getting water from the leak into the sump...?

I agree, the 5200 is awful for this kind of thing! lol Epoxy MIGHT work...I have Devcon aluminum putty, and it is great stuff...you can even drill and tap the stuff. But really, I like fixing a problem for good. I know what its like putting bandaids on. Lets say its leaking from that corner right now, but 6 months later its leaking from another? I don't like being the dog chasing its tail. lol

As for protecting the tanks with anodes.....I don't think they are. The hull is protected with aluminum anodes, not actual zinc. I already consulted with a marine corrosion expert on that matter, and aluminum with indium was his recommendation. So the anode which protects the hull, or the ones that protect the shafts, etc are attached to those items but in the water, and as they sacrifice they disappear.

How does a "zinc" (I'm assuming you mean that generically because the right material I have been told for my purpose is that aluminum/indium mix) get attached to the tank and act as the sacrificial anode?

I ask not to be smart, but because I don't know

P/F is positively charged.

Hey Rick, at the risk of sounding stupid, what is P/F? When you answer can you tell me the significance or tell me how what to search to get answers on it?

Thanks!

Keep in mind, this is the first boat of this size I have owned, although I have operated boats of this size before.

You attached a green wire to the tanks and then connect to the green zinc/alumimum loop green wire. So what are the hose fitting to the tank made off? Plastic I hope! With aliumum tanks you have to be careful with the conections. Is there anything metal touching the tank where it is leaking or close by.

Most water tanks do not have baffles, if they do you should be able to see lines where they were welded. So you keep the tanks full or empty so the water does not slosh back and forth, which can break/crack the tank. The middle diesel tank on the Eagel split a seam coming up from California, which I cut open and welded up. So you might want to think about opeing and welding the tank.

You would make dams/ wood stips epoxy to the bilge floor to divert the water to the sump. I have them in the bilge of the Eagle to divert water to the center drain holes rather than pooling at the sides, and on the roof to divert the rain water into the gutters rather than running over the sides. Once the water in the sump the bilge pumps turns on and pumps it over the side. At least it would contain the water.

Oh, you are in fresh water, magnesium or new aluminum anodes are used. I would use magnesium because its rating is 1, the lowest, zinc is 3 and the aluminum is someplace in between?

The aluminum putty would be better than 5200. Well, nothing is certain in live, if it leaks again and the putty works then use it again. Owning an older boats require compromising and thinking out side of the box. Most think being a live aboard is cheaper than living on land. Wrong! Its cheap and easier to live on land than on a boat. In our case we could not afford owning the Eagle and live on the dirt. Ok so I am to cheap!

aronhk_md said:

As for protecting the tanks with anodes.....I don't think they are.

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I believe all you need to do is connect the tanks to the boat's bonding system. But I don't know if the same practices that are used on glass boats are used on aluminum boats.

I'll need to check to see about the grounding wire there....not sure whats in place now. Yes, all PVC and plastic hoses attached to the tanks.

Although...the tanks are aluminum held in place by aluminum framing which is attached to the aluminum ribs of the boat which is attached to the skin.......are they not grounded this way?

aronhk_md said:

Although...the tanks are aluminum held in place by aluminum framing which is attached to the aluminum ribs of the boat which is attached to the skin.......are they not grounded this way?

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That very well may be true. But given the potential for Bad Consequences, I would be inclined to seek out someone reputable who makes their living dealing with electrical systems and issues on aluminum boats and run your concerns past him/her. Because what is standard practice on a glass or wood boat may be totally incorrect on a metal boat.

I'm not sure that when it comes to dealing properly with electricicals in a very specific situation I'd want to rely on assumptions and speculation from an internet forum as well meaning as everyone might be.

LOL Marin, you are totally right. Paul Fleury is that marine corrosion expert I mentioned, and I will be in touch with him again shortly. I prefer to save up a number of questions though and ask him all at once rather than bug him every time I have a question. The boat has survived 44 yrs as she sits, and I'm sure the tank question can wait another month or two.

aronhk_md said:

Hey Rick, at the risk of sounding stupid, what is P/F?

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Phil Fill

If you have two 200 gal tanks that is a LOT of fresh water. Of course it depends where you will be cruising but if it is coastal cruising in the USA you will find fresh water for topping off easily. Maybe you might try a couple of cruises leaving the leaking tank empty and see how you fare with the one 200 gallon tank, unless you have a lot of people on board it might work out OK.

Steve, you have a good point. And I may do just that. I may want to work at fixing that leaking tank though, because who knows when tank #2 may start to leak. Its the same age as the first.

aronhk_md said:

Although...the tanks are aluminum held in place by aluminum framing which is attached to the aluminum ribs of the boat which is attached to the skin.......are they not grounded this way?

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Let me offer a qualified yes.

If the tank is installed and secured by metallic straps that are bolted to structural components then it is fairly safe to assume the tank is electrically bonded. Use a meter and find out.

In the case of installations like yours, corrosion is most likely the result of local electrolytic "cells" created by contamination between things like mounting straps and the tank wall, or galvanic corrosion where a dissimilar metallic fitting is attached. Internal electrolytic corrosion can occur beneath sludge or deposits from minerals or silt that precipitated from the water over the past 44 years.

Bonding is not a cure for any of those issues, but a bonding wire from the tank itself (where you attach it may be problematic without welding on a tab or stud) to a nearby frame or structural hull fitting can't hurt and may reduce the severity of localized corrosion where the tank contacts structural members. That is where contamination collects and if you can "short circuit" the cell you may reduce the rate of corrosion in that spot.

A large aluminum tank subjected to sloshing and flexing for 44 years might be reasonably expected to suffer cracked welds that have nothing to do with galvanic or electrolytic corrosion.

The type of anode used on the exterior of the hull is so irrelevant as to be unworthy of further comment.

Hey Rick, thanks! Much of what you've said here I read in bits and pieces elsewhere since the discussion began, but you laid it out very nicely. I have a feeling there is silt inside the tanks...not sloshing stress, etc.

While the anodes on the hull didn't have anything to do with the water tanks, I do believe they had to do with another issue on the transom that I had to address. That's why I spoke with Paul Fleury before the purchase. He stongly recommended the Navalloy type anodes with aluminum/indium...until I go with a Capac or Electro Guard active cathode system.

I know this is old post...Did you ever install the bladders in existing water tanks..or has anyone installed bladders into original steal tanks. Thanks

A point of order here, but is someone actually thinking of installing a bonding wire, copper, in an aluminum boat? Good luck with that.