After living the cruiser life for several months, it became obvious that a desalinization system to turn seawater into potable water would be a tremendous advantage.
I had done some research in the past, but now redoubled my efforts. It quickly became apparent that the commercially-available systems with all the bells and whistles were going to be prohibitively expensive. I felt a simple, manually-operated system was going to be the answer.
Friends and acquaintances maintained that a do-it-yourself system could be had for $500--$1000. That may have been true years ago, but despite what the government says, inflation is making everything more expensive. My friend Jim built his own system for under $2500, but that was in 2004, and he scrounged up some used but serviceable parts. When I priced all the components needed I was near $4000 in today's money.
The heart of the system is the reverse osmosis membrane. These are now being made in common- off- the- shelf units which are reasonably priced. However many of the major players in this game do not source COTS equipment for their products. They have the buying power to go to the OEM manufacturers and ask for slight modifications to the standard units so that their product has uniqueness in the market. This of course, means that the consumer has to go back to the vendor for parts and supplies when needed. Can you detect some monopolistic activity here? This really irritates me, so I was determined to obtain a system with as many COTS parts as possible.
I wound up purchasing all the parts from Cruise RO Water. They are a cruiser's company committed to making their equipment as easily-maintained and affordable as possible.
The system is modular, allowing great flexibility in placement.


The control panel and water tank selector went into a locker just above the lower port settee.


I wound up putting the rest of the components under the settee. In the picture below you can see the settee locker with the boost pump, high pressure pump, the various pre-filters, and some of the plumbing. You can barely see the blue RO membrane pressure vessel suspended behind the filters. The red bucket is to collect water while bleeding air out of the pre-filters. It can also be used as a mixing bucket for the preservative solution when "pickling" the system for long-term storage.




When the system was first operated, it immediately started producing fresh water better than marina water. It has absolutely no taste. I couldn't be happier with the result.
The ability to make our own fresh water will make us less dependent on shore-side facilities. We will be able to save money by not needing to dock at a marina as often.

--Sorry about the lack of pictures. Someday I'll figure out how to get the pictures to show up :-)