The therapeutic benefits of a long hot soak have been know ever since man found his first hot spring. Nowadays my old body increasingly aches after a day of physical work. I therefore have had hot tubs in every home I have ever owned. So why not have one on my boat as well, even if it is a sailboat?
Luckily the Down East 45 had a bathtub of sorts built-in the aft head, but it was only a three quarters size with a tapered end, so for a six footer it was a tight waste of time
I searched the web for tubs which might fit, but could not find a hot-tub bath as such. I did find a local hot tub manufacturer, who fitted ten jets into a standard bath. It is a beautiful dark blue acrylic molding with polished brass jets and faucets.
To install it I first had to remove the built-in bath, which I thought was just a hollow molding. Au contraire! it turned out to be three thickness of ¾” inch marine plywood sandwiched with resin! It had to be chopped out with a saws-all electric saw, bit by bit, and each lump lugged to the dumpster using a cart. The whole lot must have weighed something like 300 lbs, and I think the boat came up 3 inches on her marks. We went though five heavy duty blades! After three days the bath was finally cut out, and the floor prepared for the bath.
I had to cut 1½” inches off a side flange of the tub - not to fit it in - but to get it through the companionway and along the aft corridor. Once in the bathroom it plonked down exactly where I had planned it, even allowing for its 4” inches of extra length, which fitted into the neat little alcove I had to pinch out of the engine room.
There is not enough water in the boats 11 gallon hot water system to fill the 55 US gallon bath, so a separate heater was necessary. The bath maker recommended a 1.5kw 110 volt heater, which was supposed to heat the water and keep it at 102F. This proved to be hopelessly inadequate and soon burned out the heater element.
Wth nobody to turn to, I began to research spa heaters, (isn't that usually the way?). I first learned that 110 volts is not man enough to heat a hot tub from cold, even if it is only 55 gallons. No wonder it had taken nearly five hours to warm the water.
I had previously fitted a second 110 volt shore power, to accommodate my two AC units. So, by combining the two 110 volt inputs with a double pole breaker I had a 220 volt supply. I then bought a 5.5kw heater and built in circulatory pump and plumbed it into the bath pipework. This now heats the water from cold to 102F in less than an hour. Another pump drives water through the massage jets, which can be adjusted like any hot tub.
I fitted faucets in the bath with a flexible shower pipe takeoff and this hot water comes from the boats water heater. I fill the tub from the dock hose, and it empties automatically through the shower drain