Pressurized dock water replaces your water pump
But these systems aren't designed to just connect a hose to a faucet onboard. Pressurized dock water is a system...and the system requires some plumbing: a thru-hull connection with a quick-connect for a hose on the dock and some hose and fittings to tap into the onboard water supply. Some systems bypass your water tank altogether...others go through the water tank, which is a much better idea because it keeps the water in the tank from stagnating. One VERY important caution when using pressurized dock water: the pressure on the dock is much higher than that in the onbloard system. That's why a pressure relief valve must be installed at the connection. But pressure relief valves fail, and they do so with alarming frequency. When that happens, the higher water pressure blows out a fitting somewhere in the onboard plumbing...which isn't a disaster IF you're onboard--and awake--to hear to sudden rush of water "somewhere" in the boat and turn the water off...but can sink a boat in a matter of hours if you aren't...the rate of incoming water outpaces what any bilge pumps can keep up with. (Just to give you an example of how fast a boat can fill up, one sailboat owner just took his dog out for a run...wasn't gone 2 hours...and came back to find 2' of water in his cabin. Pressurized dock water is great convenience, but NEVER leave the boat, even for an hour, without turning the water off on the dock...or better yet, disconnecting the hose. Same when you turn in at night. We have half a dozen sinkings a year that could have been prevented if the boat owners had followed that advice. So I suspect what you've been seeing in the catalogs are replacement parts, not full systems...if you think you'd like to add pressurized water, your best bet may be to talk to a boat dealer who knows how to install one.
