Dual water tanks - draw from both or one at a time?

[Ron20324]

My sailboat has 5 tanks ( 1 forward, 2 mid-ship starboard and 2 mid-ship port) with tank level monitor. I pull water off all the tanks simultaneously that way I mitigate the risk if bacteria growth in idle tanks.

And if bad water goes into one tank, it can infect all the tanks. Blue water cruisers know better than to mix two sources of water together for that reason. Better to turn off and drain 2 or 3 tanks and live off of 2. I have water in one 40 gallon tank. If it is in there for 2 weeks, the taste is different. I empty the tank after every cruise, then fill it fresh 2 weeks later. After 13 years, I can till drink the ship's water.

 

[TomY]

My boat has 3 40 gallon water tanks: One in the bow and two - athwartship under the settees, all plumbed together, with 1/2" copper, to drain equally. That was the thinking at Alden, 60 years ago.

The two things I didn't like about that set up; there's no easy way to install a gauge. And two, when you fill the 40 gallon tank way out in the bow, it drops about 4"!

Soon after getting the boat, I cut the forward 1/2" copper line and installed a gate valve. As coastal sailors, we rarely need the 120 gallon capacity. We put about 10 gallons of water in the bow tank and close the gate valve. That affects the trim little if at all.

When the two mid-ship tanks begin to get low, I can hear it in the water pump, usually in good time to fill it at first convenience. But if it runs dry, we open the 10 gallons of reserve. That solved my gauge problem, well enough.

Works for us.

 

[jssailem]

Tom a water gauge is relatively easy if you have enough height in the boat above the filled tanks.

When I got my boat I discovered the previous owner had installed a “water level” to serve as a gauge. There are a valve attached to the water line from the tank and a clear run of tubing that is above the tank when level. When the boat is at rest (and pump off) I open the valve and the water rises in the tube. With tank full the water rises to the full mark. When empty (or nearly so) the water in the tube falls to the empty mark.

Crude but functional. Not effective in a heavy sea state or if tank induces air in the line. But for the most part it serves to give me an idea how much water bid aboard and when I need to replenish.

 

[Terry Cox]

Our boat has two tanks; 65 gallon forward, 85 gallon midship. I alternate their use to keep somewhat fresh in each tank. Never had a problem with trim, odor or taste over the years. Always seems fresh as if right out of the city tap. I do use a PUR brand faucet filter on the galley sink where I filter drinking water that I keep in the fridge in a few water bottle containers.