building a water tank

[riiggs]

I am concidering building a water tank to fit into my boat.the roof is curved and i canot fit a conventional tank and cannot afford to have one made for me.I was thinking about making my own out of fibreglass but i was wondering if a fibreglass tank maybe slightly toxic?does anyone have any ideas on this?

[Dr Bradley]

i'dbe abitwaryof building my own fibre glass water tank as the stuff stinks for months after setting. If you look in the boating press (maybe Practical BoatOwner rather than the canal mags) you should find adverts for flexible, made to measure plastic tanks which may be abetter solution.

[John Orentas]

I must admit to having some curiosity as to why anyone would want a water tank on his roof.

[Guest]

I seem to remeber reading that a different resin is used for making potable water tanks, than would be used for say a boat hull.

[blackrose]

I seem to remeber reading that a different resin is used for making potable water tanks, than would be used for say a boat hull.

 

Depending on the size, a full water tank on the roof might raise the centre of gravity and affect the boat's stability. Considering GRP can suffer from osmosis it might not be the best of materials. Also as Catweasel alludes, since it's not really designed for containing potable water one might find that the freshwater might be subject to a great deal of resin migration - a packaging term referring to the transfer of elements of the packaging material into its contents. That's why for example clingfilm shouldn't really come into direct contact with fats - plasticisers in the PVC will migrate into your cheese!

Edited March 18, 2007 by blackrose

[bottle]

Riigs

 

Did say into his boat, now this may have been a typo, but even then a tank high up is not the problem when full but if only half full/empty and it does not have baffles.

 

If I remember correctly 1 gallon of water weighs 10lb and as Blackrose said it will have an effect on the centre of gravity possibly making the boat unstable.

 

Riigs I think we need more information as to what you are trying to do.

[riiggs]

Thanks for the info.I am going to put the water tank inside the the boat above my head as there is alot of room.I will put it to one side of the boat and use some balast on the other side.my boat is an exlife boat and it did have large floation tanks in the roof untill i ripped them all out so i want to use the space and save needing to pump the water up to the taps all the time.

It sounds like maybe its a bad idea to make my own tank using fibreglass. i have now found a tank that is like a poly bag and it can mould into the space i need,so i think my problem is solved.thanks again,riiggs

[chris w]

Why not use one of the collapsible bags designed for potable water and often used on GRP cruisers? They come in a variety of sizes; I used to have a 200 litre version when I had a cruiser (IIRC about £50).

 

Chris

[bottle]

Thanks for the info.I am going to put the water tank inside the the boat above my head as there is alot of room.I will put it to one side of the boat and use some balast on the other side.my boat is an exlife boat and it did have large floation tanks in the roof untill i ripped them all out so i want to use the space and save needing to pump the water up to the taps all the time.

It sounds like maybe its a bad idea to make my own tank using fibreglass. i have now found a tank that is like a poly bag and it can mould into the space i need,so i think my problem is solved.thanks again,riiggs

 

I might be missing something here but you will have to pump the water to the tank. unless you fill it with a hose or buckets.

 

1 gallon of water weighs 10lb, how big is this polybag. A 'jerrycan' holds five gallons thats 50lbs or 3.5 stone as you can see you will be getting to a significant weight and it could cause stability problems especially when not completely full or completely empty (rigid tank)

 

A polybag will need a substantial support around it.

[Guest]

If you do go fibreglass you could do worse than talk to these people:

http://www.glasplies.co.uk/

 

It is a different resin for potable water BTW.