Onboard Water Filtration for Yachts?

I've heard that water makers can be a real pain if you don't use them regularly?

Like any equipment with a couple of additional issues. Basically you regularly flush it but if it's going to sit unused you pickle it. Then you don't use the first 20 minutes or so of water after.

They can be. I've seen Algae grow in the pre-filters and stuff. Should be flushed every 2 weeks so the membranes stay wet. I've run them in any area where there is decent current and not trapped in a marina with one opening like Atlantis. Most boaters follow the rule of make water during the day and pump out at night, but that's not always the case. Pickling them is a double edged sword as many say it will destroy the membranes. I prefer to just keep them flushed.

First, we constantly run from our tanks only, no dockside water. This keeps our water fresh.

After the pump, we have a whole home 25 micron inline charcoal filter.

At the galley sink, we have an under the sink reverse osmosis filter. This supplies our ice maker and drinking water tap with very pure drinking water. This is a standard home unit that operates at low pressure (30 - 60psi) and reduces our dockside water of 180ppm to about 10ppm. The drinking water and ice tastes fantastic.

We use a watermaker while cruising to keep the tanks topped off. We just replaced our 400gpd watermaker with a 700gpd unit. I have an automatic flush add-on that I have yet to install, but I just manually flush the watermaker weekly. Maintenance is a big deal, and the payoff of unlimited water while cruising is worth it.

You state in the first line No dockside water then go on to say your under sink filter reduces dockside water to about 10ppm so I am little confused as to the use of dockside water or not.

I think he is referring to hooking up dockside water and bypassing the holding tank. On a 53 carver I used to run you could use dockside water plumbed directly into the boat and bypass the tank and pumps, or fill the tank and use that. If you bypass the tank the water in the tank could end up sitting for quite a while.

Yes, but that unlimited fresh water comes at a price of electricity and about 25 amps worth on most decent sized watermakers. Plus the cost of the membranes, pre filters etc. On yachts under 65' that don't anchor and don't have a watermaker and don't spend more than 30 days a year in the Bahamas, I tell my customers to just buy the marina water, if they don't have a watermaker already. On boats over that, 50 gph I recommend or larger, that way can refill the tank in not a lot of hours when moving from place to place.

Yes, right now we have on board 9 women, 7 who would qualify as young, 5 with very long hair. Three men on board. That's why we have 1780 gallons of water plus two 1800 gallon watermakers.

No, we've never lost that war.

I lost!

I have a homemade water maker. I carry membranes for salt, brackish and fresh water because of the places I anchor. I haven't used city or marina water in 5 years. I filter the incoming water thru 20, 5 and 1 micron 4.5x20 filters wherever I am. After the membrane I use a GAC, CTO and uv light before the tank. My tanks are galvanized steel. After the tank a GAC and another uv light. I chlorinate the tanks every year or so and then dump them. I don't care to drink even small amounts of chlorine. Membranes I'm not using get cleaned and pickled. I buy my filters by the case on ebay. I can run city water thru the post membrane filters. The private dock I stay at in the winter has no water supply and the close by marinas have bad water.

Why different membranes? Can you just not adjust the back pressure to compensate for salinity? That's how I ran my homemade water maker.

I can't understand that either. I've run lower pressure with normal membranes. For pure freshwater right around 100 psi gives you the same output as around 800 psi in saltwater. Brackish is close to saltwater in pressure.