Water tank placement

[Polishicebreaker]

Hi folks,Another day another question!

 

Time has come to work out where I'm gonna stick 600 litres of water for my girlfriend to use for washing up:)

In the boat is a badly designed integral tank in the bows( around 300 litres) I don't really want to use this and think plastic better. Options are:

 

1. Sticking inflatable tank in space at front ( no other options for 'off the shelf ' tank to fit) 300 L

And another tank somewhere 300 L

 

2. Put 2 slimline tanks on top of each other in stern 1100x 800x 330 built in to the wall/ cupboard( nicely hidden with access) total 560 L

 

3. Something I haven't thought of.

 

 

Problem with option 1 is there's no where to out another tank except the stern but then if have to plumb them together. seems easier to go option 2

 

Also inflatable tanks around 600 quid

The slimline tanks 160 each

 

With option 2 could the boat be over ballasted at stern or could I make up in the space in bows where old tank was.

At the moment uxter plate still needs to come down 2 inches. It's just sitting out of water and there's already ballast in the engine comp not to mention a big ford 4d engine.

Boat is 40 x 10

 

Any thoughts

[trackman]

If you put the tanks in the stern as described, do you intend both on one side?

If so you'll have a problem avoiding the boat listing as the level in the tanks alters.

If you put tanks each side, you'll need some interconnecting pipework to balance them up.

On top of all this, as you suggest, you will need to rearrange the ballast. Moving from 300kg of water in the bow to 600 in the stern is a major change!

[Polishicebreaker]

good question! I'm going to measure and see how central they can be, i'll get back to you on that one!

[Alan de Enfield]

 

2. Put 2 slimline tanks on top of each other in stern 1100x 800x 330 built in to the wall/ cupboard( nicely hidden with access) total 560 L

 

 

 

1) You will be in effect adding almost a tonne to the stern weight (removing 300kgs from the front and adding 600kgs (560 kgs + tank weight) to the stern. This will have a majoer effect on the trim.

 

2) If you intend to put the tanks in a cpboard / in the wall this 600kgs will have an effect on stability / rolling. You need to keep them at/or below floor level..

 

3) If you do put them on top of each other (rather than one on each side) you will be adding 600kgs to that side of the boat - you will then need to add 600kgs to the otherside (or get out 600kgs of ballast from under the floor) to keep an even-keel.

 

If you want to increase to 600 litres you really need to try and keep the 300 'up-front' (why not use the tank that is here ?) and add 300 kgs on the centreline towards the rear. Ideally you will need to interconnect them or have a 'switchover' tap.

[nb Innisfree]

We have a bow tank, not under the front deck but in the bow, ideal for access to black it. I installed the other tanks (plastic) under the pullman dining area. Holding tank is on the opposite side to act as a counterbalance.

[Polishicebreaker]

Good point regarding the height of the water storage and the effects of the water rolling around. Low is the better option then.

It's also going to be tricky to centre the tanks so I would need to counter-ballast. Also I suppose with the water level constantly fluctuating it would be constantly altering anyway.

Hmm ( scratches head) maybe I keep the integral tank until I can afford to line it, the outlet is already there so that's simple.

Something else I should of mentioned, the boat also has another low tank at the stern end of cabin which I've just cut the top of to clean and inspect. I'm not sure what this was for, maybe a fuel or septic tank but they then changed their mind on the build. It certainly looks as if its never been used. There's one outlet/inlet in the form of a threaded pipe that sticks out the top a couple of inches and goes down to the bottom of the tank. ( I'm trying to get in touch with the builder to find out what this was for)

Maybe I should now use that one as my second tank and have the pump etc at the stern although I'll then be relying in gravity for the feed from the bows tank where the outlet is low down. Perhaps time to call a plumber

[thorne lass]

1. There should be no problem with an integral tank (the one in the bow) if it can be cleaned out and painted efficiently and occasionally. We used to pressure wash the tanks out and then repaint with potable bitumen with the boat on the dock and a heater underneath to ensure a good dry surface to paint to.

 

2.

Pressed the wrong key there, but don't know which one.

 

To continue.....

 

2. The tank aft was undoubtedly intended as a black water (pump out) tank. there is no reason why this cannot be used for water although it is probably bare steel and will need painting as per the bow tank. The pump out pipe can be cut off within the tank and used as a filler. You will need a vent as well. Simply connect the forward tank to the after tank with say 22mm Hep 2O pipe or hose, then connect the after tank to the water pump, which is best located in the engine room so that it causes less damage if it leaks in the future. When filling you will need to fill both tanks separately since the 22mm balance pipe will not allow the tanks to balance as fast as you fill, but that is a small inconvenience perhaps. The alternative would be a 38mm hose balance pipe between the tanks. You will need a take off pipe at the bottom of the tank for the water supply to the pump. This is easiest achieved using a cunning rubber seal (forget the name but its a bit like a heavy duty grommet)) sold by Leesan. You simply hole-saw a hole in the tan of suitable size, fit the "grommet" and push an outlet pipe of suitable size through the grommet.

[b0atman]

what is wrong with bow tank that you are not going to use it