I am having problems with the water quality and as I was dealing with it I noticed that the bow water tank had been drawn down more than the port side tank. Maybe a stupid question on my part, but shouldn’t they been at the same level more or less?
Also is the preferred method of draining tanks to remove the hose and let the water drain out of the bilge?
Thanks as always
Eric
“Elle”
Nonsuch 30U #280
Greenwich Cove
On my 30U, under the floor in the bilge near the head door, there are two water valves so you can shut off the tanks. I use one tank at a time until empty, then shut off and switch to the other tank.
Don
‘87 NS30U Breezin’
Vancouver BC
Eric,
Responding to the first part of your question about whether the tanks should be drawn down equally, I’m not 100% sure about the physics but I’d guess that the answer would depend on whether they’re at the same level on the boat. If one tank is located higher, then I’d expect the water level in the two tanks would tend to equalize to the same level. Especially if the tanks are effectively connected by having both valves open. When all the faucets are off, the lower tank and upper tank can completely fill. But, as water is taken out through a faucet, it would also be flowing from the upper tank to the lower.
If the overflow vent lines were acessible and clear, I’d guess that the lower tank’s overflow line would have water in it to the height of the water in the upper tank.
This would lead to an upper tank draining down faster than the lower.
I don’t know the preferred method of draining the tanks. Off the top of my head, I’d suggest getting as much out as possible by other means before emptying to the bilge, to minimize the risk of the bilge pumps being overwhelmed.
– Bob
Me Gusta
Nonsuch e26U #233
You could just empty them by running the galley faucet. Or drain them into bilge by disconnecting the hose after the shut off valve into the bilge. Then use bilge pump to pump out the bilge. If too much water coming in, just shut off the valve. Also this is a good way to test both your automatic and manual bilge pumps are working properly. I did this last spring and found my manual bilge pump didn’t work, and needed servicing.
I also installed a Camco water filter at this junction.
Don
Don, thanks for water filter location suggestion as I’m about to replace the mid-tank on my boat and several old water lines too.
As I have an Excel instant hot water heater I’d like to keep the water pressure strong as the system is pressure sensitive.
Have you experienced a dip in water pressure with the addition of the Camco?
Ed Strazzini
NonsuchPelican@gmail.com
N33#36
Deltaville, VA
I have not noticed any change on water pressure. But I don’t have a gas water heater, mine was removed and replaced with a hot water tank aft of the engine by PO. Where I put the Camco filter, there was previously a Jabsco screen filter to protect the water pump, so easy spot to put the Camco. Plus its readily visible as a reminder to replace it annually, and easy to do. I wrote the install date on it too.
Don
I believe, that most 30s, like mine, have the same setup as Don. I have a large filter canister located there for clean water. Always use one tank at a time otherwise you will suck air from the other.
Joe Valinoti
S/V iL Gatto NS30U #221
Sea Harbour YC
Oriental, NC USA
I always use one tank at a time. I also use a filter but attach it to end of hose when I fill the tanks.
Half way to Tortola from Norfolk during a 1500 rally one year we thought we ran out if water. The owner had both valves open and when one of the tanks drained the pump was drawing air but not water. The other tank had plenty of aqua.
Best to use one tank at a time to avoid suddenly being out of water 
What we do is drain from one , then open both valves overnight giving us two half tanks. Close one tank. when you run dry time to fill up.
Got the idea from Bob Jenkins
We have a small filter in our bilge that filters out course stuff from our water. To drain the tanks, we pull the clear cover off the filter and let the water drain into the bilge to be pumped out. If anyone is worried that their draining tanks may overcome their bilge pump, I suggest you get bigger pumps - the amount from our tanks is nothing compared to a hole below the water line.
In the fall, after the tank has drained, I next use a shop vac to get the balance of the water from the tank and then stuff a plastic tube into the outflow line from the tank and blow out the line. We run anti-freeze into the plumbing (but not the tanks) via an attachment that goes where the filter was - allows me to pump straight from a bottle into the plumbing. Only takes a gallon or so, including the propane fired hot water heater.
lloyd herman
Rendezvous, 30U
Port Washington, NY
I installed a T in the line downstream of the tank selectors to pump T. There is a short length of hose (1 metre) with a shut-off valve in its centre, leading from the vertical of the T. To drain the tanks into the bilge you open this valve and the tank valves. To put antifreeze into the lines for winter, place the end of the line in a jug of antifreeze placed in the bilge, close both tank selectors and open a faucet until you get antifreeze coming out. I find this much easier than pulling a hose off one of the fittings to get into the system.
Peter Moodie
Nonsuch 30U 366 ‘Catalyst’
Sidney, BC/Winnipeg, MB
Thanks for all of the help. Bought my boat during Covid so I am learning everything the hard way… Any tips on how it keep the water fresh in the first place would be appreciated.
Eric
NS30U 280 - Elle
Greenwich Cove, CT
West Marine has a good article on that subject
Joe Valinoti
S/V iL Gatto NS30U #221
Sea Harbour YC
Oriental, NC USA
