Dock water hoses can be seen connected to lots of boats in marinas, particularly where people live aboard. A hose connects from a dock faucet to a pressure reducing inlet on the boat and pressurizes the boat’s water system.
Advantages are: constant pressure in the boat’s water system without using any pumps or battery power—which also means no noisy pumps. The supply can often be a more even flow to say a shower, instead of using a small pulsating pressure pump. Also, if you live aboard it saves having to fill the tanks.
BRITANNIA had this system built-in from original, and we liked the advantages and convenience. But when one of the old connectors broke I realized there was nothing to prevent the boat completely flooding, and even sinking if nobody was on board to hear the bilge pump running.
My thoughts turned to how to make a fail-safe system, because there was no accounting for internal failures. We always switched the water off on the dock when we left the boat, but that’s not foolproof, because it’s easy to forget.
The most obvious foolproof remedy was not to use a dock water hose at all, and draw from the tanks, refilling them as needed. But you might say the same about a shore power electrical supply, which everyone uses without a second thought, but which have been the cause of many an electrical fire.
As a cheap added safeguard I fitted a second shut-off tap at the hose/boat connection, just in case anyone switched the dock faucet on again. This was still not an automatic safety measure, so I considered how I might install some sort of automatic shut-off.
I found a 12 volt solenoid water valve at Sizto Tech Corporation, in Palo Alto, California, for $74.25. It is normally open, but instantly closes when voltage is applied. I connected it directly after the pressure inlet, and wired it to the bilge pump float switch. On tests it closed flawlessly, but when the bilge pump lowered the water and the pump switched off the valve opened again and the cycle repeated continuously To prevent this I incorporated what is called a latching relay from Xoro.com for $22.89. Part # 785XBXCD-12D. This works like a normal relay except when activated the secondary circuit stays live and keeps the shut-off valve closed, even when the primary power disconnects. The relay only powers off when the circuit is manually switched off at a breaker.
I also wired a bell into the circuit, which rings when the system is activated. In other words, the boat now has a high water bilge alarm which is required by many marine insurance companies.
Feeling very satisfied with myself, I decided to find out how many boats in the two marinas in Titusville, Florida, used shore water hoses. Out of a total of 20 boats with direct shore water connections I managed to actually ask the owners of 12 if they had any fail-safe method, in case an internal failure. Amazingly absolutely none did! They all relied on remembering to switch the water off when they left the boat, or hearing the bilge pump working it’s socks off, if they were aboard!
I feel much happier with my safety system, knowing that even if I forget to switch the water off, there is a measure of automatic safety