TOM NEALE: I would install that check valve. The typical
12-volt water pump will have a valve within it that should keep
water from backing up into the tank. But I wouldn’t rely on
that alone for the purpose of avoiding shoreside water backup.
Installing a check valve designed and
intended for this use is the best practice
in my opinion. There will be less stress
on the valves in the pump.
Often the valve system in the pump
is essentially the diaphragm system that
draws and sucks the water. This is not
specifically designed for the usage you
intend and could be impaired. Install a
quality valve so that the boat’s 12-volt
pump won’t have too much interference
pushing water downstream through it.
Consult the manufacturer of your specific pump.
Here are other precautions that I
would take: Install the pressure regulator
in the dock hose before the dock water
comes into the boat. Also, have a pres-sure-relief valve in your boat’s system that
discharges overboard in case of over pressure. The ABYC Standards address several aspects of this subject of which you
should be aware. The Standards include
H- 23. You can get a free five-day trial
period by going to its site and clicking on
“membership” at the top of the page.
Never leave the boat for more than
a few minutes without turning off the
water at the dock. (I have a valve on deck
at the point of entry so I remember to
turn the incoming water off there.) Be
sure the dock hose used to get the dock
water into the boat’s system is made
for potable water; many garden hoses
Engine in a flooded bilge
Rainwater recently filled up my boat’s
bilge. How should I clean up the inboard
engine and verify that there’s no serious
damage? The motor does crank OK
on the trailer. Alan York
ASK THE EXPERTS
EDITED BY TOM NEALE
ASK OUR EXPERT Our technical editor, liveaboard and DIY guru Tom Neale, creates this column from correspondence
with our members. If you have a boat problem that you can’t solve, search our website for answers.
Water where you want it
My boat has a 50-gallon freshwater tank that is sufficient for short trips. My existing pump draws from that and supplies the sinks and washdowns. Now I want to
connect freshwater from the pier when the boat is in the marina slip. I understand
that I would need to use a pressure regulator to reduce the pressure to 25 pounds or
so. If I connect the output of that regulator to the output from the existing 12-volt
freshwater pump, will I need to install a check valve to prevent water from backing
through the pump and into the tank?
Larry Whitaker, California