Filling fresh water tank from shore water hook up

J

joelkoz

Member
Sep 9, 2012
57
Delray Beach, FL
Boat Info
eSea Street - 2001 560 Sedan Bridge
Engines
CAT 3406E
Everyone knows (or should know) that the shore water connector has nothing to do with the fresh water holding tank. If your fresh water tank is near empty from your last trip, and you connect to shore water, you get unlimited water for showers and such, until you disconnect, in which case you are out of luck if you didn't take the time to refill the holding tank.

Anyway - being a lazy sort, and also starting to tinker with customizations, I've been thinking of installing a valve on my boat that would re-direct the shore water inlet directly to the holding tank, so it DOES fill up the tank. That way, my "procedure" would be:

1. Return from trip
2. Connect to shore water and turn on
3. Turn valve to re-fill holding tank
4. Turn valve back after holding tank full to resume normal shore water use

That would be a lot less fiddling with hoses.

If I can get the above to work, my next step would be to figure out some type of "auto-fill" process that would handle steps 3 and 4 without direct intervention.

In any case, anyone know of a reason why the above would NOT work? As far as I know, the holding tank is NOT pressurized. I'm guessing that the plumbing in the boat is pressurized AFTER water is removed from the holding tank and sent thru the pumps. Is that correct? If so, I think I could just tap directly into the line connecting the water fill cap to the holding tank with another one tapped from the shore inlet, connected with a Y-valve.
 
Good idea! I did the same thing with an old motorhome. The only thing I had to be careful with is filling too fast, the vent on my tank was small and I had closed off the old fill point as it spilled water every time I put on the brakes! Inever thought bout the autofill idea, thatwoul be cool.

jerry van
 
The only concern that I would have would be the potential to overfill under pressure. The water fill hose/line, overflow vent and even the tank itself is design for gravity feed and we really don't know what might happen under pressure. You might need to remove the water fill cap just-in-case you overfill and make sure there is a way for air to freely escape during the pressurized fill.

Mike
 
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I saw a sailboat sink at it's slip when the owner turned on the valve and went in his house and forgot/took a nap. The next morning, the boat was under water.
 
If you used a floating ball valve, like in your shop vac or toilet, you could have the fill stop automatically when the tank was full..
images
 
RollerCoastr said:
Formula offers this ability from the factory. It might be worth investigating their method.
Click to expand...

My friends with Formula boats have that system and don't like it. It just complicated a simple system, there isn't a deck fill at all...I think you have to move a switch (electric) to fill and then back off again.
 
Good idea, however I'd pass on it. I flush my system a couple of times a year with a diluted bleach solution. The overflow at the fill point allows me to fill as fast as I want. Although, I wish the location of the water fill point and fuel fill points were more convenient.
 
I have a fill system as described. I do have a water tank deck fill, but never use it.

I placed a T fitting in a cold water line just downstream of the shore water inlet. A solenoid valve opens via a switch on the panel to fill the fresh water tank which has a T installed in the fill pipe. There is still manual intervention to stop the fill process when the tank is full. If I do forget to switch off the tank fill process, there is a separate overflow that allows the excess water to go overboard. I assume (maybe incorrectly) that all water tanks have this overflow. All of my previous boats have had this. I assume that you could also forget to stop the fill process if doing so through the deck plate but possibly, the overflow would be through the deckplate that would be already open with a hose in it.

I continually run water through my tanks on board. I typically fill the tank and then switch back to on board pumps. When the tank gets low, fill the tanks by switching off fresh water pumps, and switching on solenoid to fill tanks. Both switches are located on the panel, so as long as you are connected to shore water, the fill process is as simple as two switches.

Been using this for two seasons, no issues with this system.

Nothing is fail safe but a few things to consider:

If solenoid fill switch is on with on board water pumps on and shore water NOT connected. This would result in a "loop" in the system. The water would run through the on board pumps from the tank through to the fill solenoid which would be open and back to tank. This would mean water pumps would run continuously with lower pressure to the rest of the system. Could burn out water pumps but never fill system with additional water.

If solenoid fill switch is on with on board water pumps on and shore water IS connected. The same loop results but the pump pressure does not allow my system to pull water from the shore water.

If solenoid fill switch is on with on board water pumps off and shore water IS connected AND you forget to turn off the fill process. Tank fills and overflows overboard.

Of course, leaving shore water connected on an unattended boat is not a good idea, so I always disconnect shore water if I am not on board.

Making the fill process an "automated" stop when full is a little more complex, but can be done. The tank monitor would need to be more sophisticated so that it can send a signal through to some sort of switch to shut off the fill process.

The end result is that once I return to the dock, I connect shore water and will have an easier way to fill the tanks prior to departure.
 
I never leave city water connected to the boat. The pressure (even with a pressure regulator) could go high enough to break a water line or fitting and flood the boat.

I fill the tank when it's getting below half full (we hold 200 gallons of fresh water) and use an inline water filter to remove things that make the water taste bad.
 
VC117068l.jpg


Here is a low tech option if you really want to do this.
Dare-O-Matic Nonsiphonig Float Valve.
 
I wouldn't use any automatic means of refilling the tank from a hose at the marina unless you know that every hose bib in the place has a back flow preventer on it. While unlikely, it is possible that you end up siphoning sea water, or even waste from a holding tank into your system if some idiot leaves a hose hanging off the dock or shoved into his holding tank.

An even bigger risk is that your water at the slip is likely supplied thru a water system installed and maintained by the marina operator/owner so you never know when the system has been breeched for a repair or a leak.

I just don't take chances and we handle the risk by filtering every drop of water we put in our freshwater tank thru a reverse osmosis filter we installed on next to the water faucet on the dock.
 
fwebster said:
...I just don't take chances and we handle the risk by filtering every drop of water we put in our freshwater tank thru a reverse osmosis filter we installed on next to the water faucet on the dock.
Click to expand...

Tell me more. I can't fathom the size of that thing.
 
Great feedback guys. A couple of comments:

1) I to never leave the shore hose pressurized when I am not on board (unless it's a quick run for lunch or dinner)

2) My marina's water comes from city water


3) I was planning on putting water filter inline with this new hose. I already have a Seagull IV at the kitchen sink for drinking water, but it never hurts to clean the water for teeth brushing and such.


4) I was not going to disconnect the deck fill, so that would remain an option


5) By "automated" I was thinking more "manual start, auto shutoff". That way, I could avoid questionable water supplies mixing in with the holding tank.

I love the idea of the solenoid valve and switch vs. a manual valve. That is even less effort! It would also get me one step closer to automation.

I found some info on the web about using capacitive sensing for liquid levels. I may start experimenting with that. I like the idea of having a digital read out of exactly how much water is in the holding tank. With 200 gallons, "1/4" is still a lot of water, assuming it's closer to 50 than zero!

I'm going to investigate some of the ideas here for dealing with overflow and pressure buildup and factor that into the mod design.
 
dpmulvey said:
Tell me more. I can't fathom the size of that thing.
Click to expand...


Actually, it is quite small. I got it from Amazon a few years ago and forget the manufacturer, but recall the cost was about $250. I get the prefilters from Lowes. I mounted the fiter assy. on the end of my dock box and the tank is next to the power pedestal so it isn't in the way for me or my neighbor.
 
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