Built In Fiberglass Water Tank

[Styx]

I have a S2 8.0c with an aluminum 20 gallon water tank. I have removed the water tank (doing a complete re-build from hull up). I have read a number of articles that aluminum is not the best for water tanks. I have also noticed that there is a lot of empty space on the sides and back of the tank. I am considering building an integral fiberglass tank that will use all of the space. (guessing I will gain 10 gallons or so making it a 30 gallon tank). I have also notice that I have unused space in the bow under the bed. I am not talking about under the seats for the table, but forward of them. It is a big space. Without doing the calculations, I bet there could be room for 40 - 50 gallons.

Has anyone built their own fiberglass water tank? I know that I need to use FDA approved epoxy. I can get Reichhold Dion ISO 6631T isophthalic polyester resin. I can buy it from Merton Fiberglass.

Does anyone have thoughts about adding a water tank in the bow. I know it will add additional weight. Will that be an issue?

Is there anything I am missing? All thoughts, ideas, suggestions, and pictures are welcome.

 

[Steve Dion]

Why not have a poly tank? Either custom or off the shelf.

Www.Ronco-plastics.com

 

[Old Skool Neil]

The older Columbia/Coronado's had integral water tanks. Speaking specifically to the Coronado 35 center cockpit, the tank was part of the port settee in the molded interior liner and after installing two 3/8" (if I recall) nylon thru hulls in the aft end panel (one discharge, one vent) a lined plywood top was screwed in place. The fill plate was installed in the tank top requiring a hose to be brought below for filling.

I hope the lining on the underside of the top was Formica but I seem to recall it was MDO.

 

[Patrick S/V Shangra-La]

The poly tank sounds like a good idea....Remember though as you add gallons you add pounds. That boat was designed for only so much extra weight to sail correctly. As you add weight you loose performance.

Just make sure you are not "shooting your self in the foot" with too much water on board.

 

[kloudie1]

I helped to seal a leaking integral fiberglass tank in a Beany Toe 43.. The inside of the hull is the bottom and the liner grid is the top and sides .. The sailing induced flex between the liner and the hull skin broke the sealant that Beneteau had used.. so be careful of the configuration..Aluminum is not that bad if properly constructed and installed. If it is not leaking now and an inspection says you don't have corrosion (inside and outside) then it would seem to be a good material to have lasted these many years.

 

[woodster]

i had to replace my water tank on my 9.2....i checked in to doing a built in and also asked on here ...but for some reason i cant remember what right now i decided to just go back with what i had......i checked with trionic and ronco and coul get the tank in polly but the freight was as much as the tank and i was not willing to pay for he tank twice.....so i just had the sheet metal shop make me the tank parts and welded it up myself and put it back in .....

regards

woody

 

[Old Skool Neil]

The problem with aluminum water tanks is the formation of disgusting stalactites on the top.

My previous boat had stainless water tanks that as far as I know have performed well for 26 years. My current boat has a poly tank that is fine but is not used for drinking.

 

[FastOlson]

Choices....

For drinking water, go with SS, or with good quality roto-molded plastic, or with fabricated custom hot-air-welded plastic. The later absolutely must be constructed correctly by someone who really knows how to do it.

After almost two decades of water and fuel system upgrades to our boat, we nowadays have a larger aluminum diesel tank (right material), a very custom drinking water ss tank - shiny inside and out, with double clean-out ports, and another custom welded plastic aft water tank. The welded plastic one was replacing a Ronco tank that was just wrong-shaped for the area and they did not have one that fit any better.

The ss one increased water tankage under a settee from the stock 23 up to 38 gallons -- and of course used the available space a LOT better.

Note that adding a lot weight in the ends of the boat does change how it floats and handles under way, too.... so add up the weight changes and be real careful.

I love the variety of Ronco tanks, and their quality and service are both top notch, by sometimes it's just as cheap to go with other avenues.

Good luck,
Loren

ps: and as pointed out by others, aluminum alloy is not recommended for drinking water tanks. Do use the 5000 series alum for your diesel tanks tho.

 

[thinwater]

Yup, built a FRP potable and FRP fuel tank for my last boat. Yes, chose the correct resins, give good thought to mounting, baffles, drains, and construct with nice filets and a smooth resin-rich finish. No problems with either for the 8 years I owned the boat.

Yes, weigh in the bow seems like a problem. As long as you are building a tank, can you find a better place near the CG and store on light things in the bow?

 

[Styx]

Thank you everyone for your input. I will do more researching and when I decide, I will post a few pictures.

 

[Scott T-Bird]

I suppose that you are thinking that the water storage would be good to have for extended periods on board, but, how much water do you think you really need to carry on your 26 foot boat? It sounds like the amount you are contemplating would start to affect the way the boat handles.

OTOH, what about your other storage requirements, such as holding tank and fuel? Does it make sense to go overboard with the water storage and limit the other storage requirements?

 

[Styx]

Good point Scott. The fresh water storage is 20 gallons. I do not have a holding tank, I have a composting head. And yes, the fuel storage is small, it is also 20 gallons. I am working on increasing my fuel to 30 gallons. I have removed the icebox and turned it into a storage area. I think that 20 gallons of water for 2 people is too small. As I look at the wasted space around my current water tank, I am sure I can increase water storage there and maybe not us the bow area at all. Being able to throw out ideas and getting help is what I really like about this forum. I am not sure exactly what I will do.

Thank you everyone for your input so far.

 

[Ron20324]

Years/decades ago one of the sailing magazines had a DIY article to build in a water tank. Sorry, I don't recall how long ago or which magazine. I do remember that the top was removeable, as post #3 mentioned.

 

[Alan Gomes]

Good point Scott. The fresh water storage is 20 gallons. I do not have a holding tank, I have a composting head. And yes, the fuel storage is small, it is also 20 gallons. I am working on increasing my fuel to 30 gallons. I have removed the icebox and turned it into a storage area. I think that 20 gallons of water for 2 people is too small. As I look at the wasted space around my current water tank, I am sure I can increase water storage there and maybe not us the bow area at all. Being able to throw out ideas and getting help is what I really like about this forum. I am not sure exactly what I will do.

Thank you everyone for your input so far.

For additional water capacity how about adding a flexible bladder type of tank? I'd never consider using one for holding waste but since you are talking about water this might be a good way to go as far as easy mounting options.

 

[Styx]

Thanks Alan. I will have to check out a flexible bladder tank. Not sure where to get one, but I will do a little searching and see if it will fit the bill.

 

[Alan Gomes]

Thanks Alan. I will have to check out a flexible bladder tank. Not sure where to get one, but I will do a little searching and see if it will fit the bill.

You could look here for starters: http://www.westmarine.com/webapp/wc...toreNum=50632&subdeptNum=50638&classNum=50644

 

[Chris Patterson]

I have one of those bladder tanks forward. Works brilliantly.