mounting the watermaker

I've been thinking through the approach i'll take to mounting the watermaker, and have come to a few conclusions.... I also have a couple of 'niggles' to deal with....

The area in the transom where it will go will have to hold the watermaker itself, and the seperate pump unit.... ideally i'd like the pump unit in the engine compartment to minimse the electrical run, and also to keep it as low as possible (the closer it is to/below the waterline, the less work it'll be doing, and therefore the less current it will draw), but there simply isn't room, so it'll have to go behind the watermaker.... this carries its own issue, in that it will make it a bit harder to change the filter, but i'll have to live with that....

Its a 5 micron filter, and I suspect that using it anywhere near the east coast will neccessitate regular filter changes with the silt laden water that we have around here.

The inside of the transom area is sloped/curved as you would expect, so in order to get a level mount for the pump and watermaker, I need to build a couple of plinths.... these will be a single sheet of thick wood (around 3/4") and feet at either end that are shaped to match the hull contours... I measured up for this, and will make it up at home, and then will need to fine fit when on the boat.... the plinths aren't very big, so wont need central support witha 3/4" plank, which is good as it will make the fitting a lot easier....

These plinths will then need fixing to the hull..... I won't be screwing them down as I don't want to be screwing into the hull (!), so will be gluing them down.... options are to epoxy them in, or to use a strong adhesive such as Sikaflex 291..... at the moment, I am erring towards the Sika route, as it is quicker and cheaper.... plus has a kind of 'high build' quality, so will allow for some minor errors in shaping the 'legs'

Onto these, at the front will be the watermaker (facing the locker entrance), and behind in parallel, the pump... this will mean that the Manometer (pressure guage) and flow meter will be visible through the locker entrance....

I will then finally have to plumb it in...

There is a 3 way from the seawater intake to the pump.... one direction draws seawater, the other to a loose pipe that can be placed in freshwater to 'wash' the watermaker if it is to not be used for a few days.... eventually I will plumb this loose pipe into the main tank, via an activated carbon filter (which removes the chlorine - which damages the membrane) so that a wash is a simple matter of switching the valve....

The other side of the pump goes to the watermaker itself....

This leaves two other pipes.... the first is the brine, which will need venting overboard.... I'd like to tee this into an existing skin fitting if possible to avoid making yet another hole in the boat, but not sure yet if there is an obvious candidate....

and the second is the fresh water itself... called the 'product'... this is easier at face value, as it can just be teed into the inlet pipe for the tank.... right by where I am fitting the watermaker is the airvent/overflow for the tank, so this is the perfect place to plumb in.... However, there is one remaining complication..... when the unit has been left to stand for a while or 'pickled@ run with chemicals to allow it to stand for long periods unused), then the first run (up to an hour if its been pickled) needs venting overboard, so I need to work out how to tee this product pipe and vent it overboard..... so another 3 way valve required, and possibly even a skin fitting.... or I may be able to get away with fitting a valve in the vent pipe between the tank and the tee so that it forces the product water out of the overfow... an option to be considered....

Finally, the pickiling itself..... if the loose pipe is plumbed in, then I need yet another 3 way valve so that I can have a loose hose to run to a pickling source (usually a bucket!).... this may have to wait until I plumb the loose hose into the main water tank....

These valves will all be mounted on the rear on the bulkhead that forms the aft locker (lazarette) which again isn't perfect for accessibility, but then again, not that bad, and they won't be used every day.... in fact if the watermaker is being used every day, then they won't need touching.... only when it is being left for more than a few days, or at the end of the season for pickling...

I have looked at motorised valves as an option.... I can then put switches for the whole lot on the instrument panel... and with some careful consideration, and use of some intellugent switch combinations, reckon i'll be able to have 1 master switch, a second for wash, and a third for pickling.... need to work that through properly though, and won't be rushing to do it.... the motorised valves are £85 each!

So.... i'll build the plinths this week with a bit of luck, and then can mount them next weekend, and leave the sika to set for a week, and then fit the watermaker the following weekend.... i'll worry about the plumbing and wiring after that!