Fresh Water -air lock

[pfrinaldi]

I have a Pearson 323 with 3 fresh water tanks, bow, port and starboard. When I run off the bow tank the system works fine but when that tank runs out and I switch to one of the others the system air locks and I have to physically prime it. Most of the time I have trouble whenever using the port or starboard tanks. I've replaced the original pump with a surflo and it is mounted about 6-inches higher than the highest piont in the system.

All of the vents are clear and the tanks run freely when I disconnect the outflow fitting.

Has anyone experienced this problem and found a solution?

 

[Mike G.]

I own a 1977 (#2). My foward tank was converted to a holding tank.
However, I encountered the same problem when I first purchased the boat.
That first season, valves for port and starboard tanks were always open. I discovered that only one valve can be opened at a time. Are you closing the valves on the empty tanks?

Mike

 

[Ariel]

I fought this same problem for fifteen years on my P36-2. I relocated the pump up and down, rotated it to pump on top and pump on side. The air locking didn't change.

The only solution I could come up with was to not let the tank run dry, but that was hard as we live and cruise on the boat during the summers.

I investigated all the tank gage systems made at the time but did not find one that was reliable or did not require considerable work to install.

Having spent my career designing refineries, I decided to make my own. The picture shows the level gage on the bow tank. If you look carefully you may see the water level in the tube. It gage is made from 3/4 inch polycarbonate (Lexan) tubing, connected to a tee in the tank outlet line. The tube is slightly taller than the tank. The cap is a chair leg protector with a 1/16 inch air hole drilled into it. The gages are now over eight years old with several thousand sea miles on it without insident.

Some time ago someone wrote an article in Good Old Magazine about a simillar system he made from small diameter vinyl tubing. Try a search of the GOB archives for that.

Ask if you have any questions.

Dave
s/v ARIEL

 

[pfrinaldi]

Yes, I'm only running off one tank at a time. I'll try changing tanks before the bow empties.

Thanks
Pete