01 May 2016
One of the vital necessities onboard any boat is fresh water. You can only carry what your tanks can hold, and depending where we are, water may not be available where we go, at least not in the quantity or quality that we want to stay safe from dehydration or even disease.
Water making systems have been around for a long time and most cruising boats have them, but they are be expensive, depending their complexity and capacity, but they all follow the same principle: when you force sea water through special membrane under high pressure about 10% of it becomes drinkable fresh water and the rest is pumped back overboard as “brine”.
As with any system there are tradeoffs. Although there is a seemingly inexhaustible supply of sea water around us, the system to pump it through a membrane and into your water tanks takes power; there are systems that use 12 volts from the batteries (like ours) and others that require your engine to be running. The membrane has to be clear of debris and can’t come in contact with any petroleum. The pump and the lines it supplies generate several thousand pounds of pressure to get the water through these membranes and all need some maintenance.
Brilliant came equipped with a rather dated system that had been laid up for several months when we purchased her. What we didn’t realize was that the production stopped on this version in about 2001 and spare parts are, shall we say, in short supply. While some of the components are common to all systems there are particular parts that aren’t necessarily interchangeable.
So, with other priorities looming we didn’t resolve the issues with our water maker before leaving the States, believing from our experience that we could find sufficient fresh water along our path until we reached the USVI, where we know of resources to assist us if necessary; now that we’re in St. Thomas this project floated to the top of the list.
Over the last several days, I had the membranes (2 of them) replaced by a local vendor since the housings were not replaceable if damaged; I replaced the seals and O-rings on the pump; I had some new high pressure tubing made to replace tubing that was leaking, repaired some rubber motor mounts, and repeatedly worked with the system to contain the leaks caused by the considerable pressure needed to do its thing.
After several days of work, accompanied by the expert advice of some invaluable cruising friends, I have successfully made drinkable fresh water from sea water onboard Brilliant while on a mooring in St. Thomas USVI. The system needs some tweaking and is not fully reinstalled yet but I now feel a whole lot of “oneness” with my water maker having torn it apart and put it back together again.
Please keep fingers crossed that it will serve us adequately for some time. This would relieve us from having to find potable fresh water in the countries that we visit and transport it out to the boat; one less chore on the list.