Fresh water equalization

[rvolkwein]

I just de-winterized my 2002 Mainship 390. After flushing the tanks and filling them with fresh water I find that the tanks do not equalize. The port tank empties while the starboard tank is still full. It appears to me that I have a plugged line. Does anyone know where the line is and how to access it? Thanks

 

[caltexflanc]

Or a plugged vent. Or a valve that got closed.

 

[johnma]

the same thing happened to me on my 2003 390 today. As it turns out, when i was winterizing last October I shut off the valve in the line from the starboard tank to the pump. Ran out of water halfway through a shower. Checked the tanks, and saw the port was empty and the starboard was full. Only thing can cause that is a plugged line(not likely) or a closed valve (very likely). I opened the valve and the problem was solved.
John
2003 MS390

 

[rvolkwein]

John, where was the valve located on you vessel, back by the tanks or on the valve chain located under the helm?

 

[MikeM]

So should the valves on both tanks be left open? I've been drawing from one tank at a time. For some reason, I assumed they should not be open at the same time.


Mike Metts
KK 42-165
Virginia Beach, VA

Sent from my iPad using Trawler Forum

 

[Larry M]

So should the valves on both tanks be left open? I've been drawing from one tank at a time. For some reason, I assumed they should not be open at the same time.


Mike Metts
KK 42-165
Virginia Beach, VA

Sent from my iPad using Trawler Forum

We have 2 tanks and use one at a time. My thinking is if we have a failure after the tanks, I only clean the bilges with one tank. Also, we use a water maker when out. The water goes into the tank we're drawing down from. If the membrane on the water maker fails, I've only lost one tank and still have a reserve.

 

[johnma]

my valves are on the bulkhead just under the pump.
John
2003 MS390

 

[souzaham]

Since the 390 has a natural list to port I use that(port) water tank first then switch over to the starboard.

 

[Phyrcooler]

My 390 doesn't list. Did they forget to install something?

BTW, my valves are all under the starboard berth of 2nd stateroom, along with the water heater. She has 3 fw tanks; 2 aft, one midship center bilge area forward of ER

 

[johnma]

Phyrcooler, what year is your 390? I have 2 fresh water tanks aft. one on each side. The center midship tank on my boat is my holding tank
John

 

[David O]

I believe it all depends on which engine package you have. I have twins, so the holding tank is in between the engines. I have 2 plastic water tanks aft and 1 aluminum belly tank in the center bilge. Each tank is valved at the water pump on the ER bulkhead.

 

[H2oplayer]

I believe it all depends on which engine package you have. I have twins, so the holding tank is in between the engines. I have 2 plastic water tanks aft and 1 aluminum belly tank in the center bilge. Each tank is valved at the water pump on the ER bulkhead.

I have a 99 and it is the same as this. I usually leave the valves for the aft tanks open and save the forward tank as my reserve.

 

[Mr.Nulook]

I found the water tank vent was clogged and did not allow the water to pump from the tank. A quick test is to leave open the fill cap to see if it levels out. I found the vent hose was pinched between the inner and outer hull when the boat was made. Ran a new vent hose and it worked fine.

 

[AusCan]

So should the valves on both tanks be left open?

Mike,
I'm in favor of drawing off one tank at a time; both for water and fuel.
Having the tanks equalized doubles the total volume of possible leakage should a hose connection fail.

Another issue is - once the boat starts listing for any reason, such as an imbalanced load or cross wind, the problem starts compounding as even more water and/or fuel crosses over to the lower tank.

One item on my to-do list is installing a small inline pump to transfer water to the windward side to minimize heeling when motor-sailing on a long continuous tack.

 

[rwidman]

If you have two tanks, one on each side, doesn't it make the most sense to use them both at the same time? Treat them as one tank?


That not only equalizes the weight of the water you are carrying (from side to side) but it's the simplest. No fooling with valves, no checking to see if one tank is almost empty and less worry about a tank running dry and the pump continuing to run trying to pressurize the system. And if you want to install a level indicator, you only need to install it on one tank.

 

[Mr.Nulook]

If you have two tanks, one on each side, doesn't it make the most sense to use them both at the same time? Treat them as one tank?


That not only equalizes the weight of the water you are carrying (from side to side) but it's the simplest. No fooling with valves, no checking to see if one tank is almost empty and less worry about a tank running dry and the pump continuing to run trying to pressurize the system. And if you want to install a level indicator, you only need to install it on one tank.

Yes. I agree to use both tanks at the same time. They designed the fuel and water to be some what the same weight on both sides of the boat regardless of what level they are at.

 

[AusCan]

The best answer may depend on your hull shape.

If all other weights are always balanced, equalizing the tanks works well. On a hard chined boat this may be the best option.

With a rounded bilge hull such as mine, the boat starts to list with minimal extra weight on one side (one person). Then the cross flow starts making the boat list more if the tanks are equalised. I prefer to control the weight transfer.

 

[porman]

Our Camano Troll had both port and starboard fuel and water tanks. With all four tanks full the boat sat down on the port side. It was worse with people sitting since all seating was on the port. I ran with just the port tanks open until the boat sat level, and then alternated side to side. Access to the valves was easy so that wasn't a problem.