The first thing you should do is think through as to how much water you will need during a normal day for cooking
, washing dishes and clothing
, bathing, drinking, etc. That will define the volume of water you would need to produce.
A bit more information on my system. It is a AC system which I run with a 2000 watt Honda Generator
and it produces 11/gph which is sufficient for my wife, 1 1/2 yo little girl and I- I run it every couple of days for 3 hours and charge my batteries and do other AC stuff as I make water.
If there are 2 or more people on your boat you will need a system large enough to make about 15 to 20gph. 12V will not provide that kind of power and you would be running he system all day and using a whole lot of diesel fuel
to tun the engine. You will need either engine driven or AC with a genset. Engine driven systems get more expensive and complicated but produce higher output in shorter periods of operation.
What size system are you looking at that will require a 1200PSI pump? Most membranes operate at just under 1000PSI as does my system. Look at March Pumps they are the most popular for this type of project
and have a VERY GOOD reputation. Depending on your system you may need a second smaller boost pump to bring sufficient salt water
volume of water up to the HP pump.
As far as pickling the system, you only need to do that when you are not going to be using the system for a more that several weeks. What one needs to do at least once per week is to do a back wash on the system to clean the membrane and HP lines.
I donīt know what your sailing plans are nor where you plan to go but if you plan on cruising for extended periods with a water maker you need to design it to slightly exceed you water need. All of the above been said, I cruised the Eastern Caribbean
for 12 years w/o a water maker. I donīt stay I marinas
unless absolutely necessary and after a while got tired of hauling 6 gallon jerry jugs of water to the boat to replenish my water. I have a 100 gallon tank which will last me 2 weeks w/o adding any water.