When it was built in 1977 my Down East 45 foot schooner Britannia had built-in bathtub—of sorts, in the aft cabin en-suite bathroom. It was only a short tub with a tapered end, so for anyone over about five feet it was an uncomfortably tight squeeze, and for me at six feet it was practically useless. It held roughly 40 gallons, so the boat’s five gallon water heater was also totally inadequate to even draw a luke warm bath.
My first thought was to rip it all out and install a shower cubicle, which could have been quite large and modern looking, with a nice Plexiglas door engraved with some nautical scene. That would have been a relatively easy and inexpensive modification.
However: in the process of taking measurements it became apparent that if I encroached, just a bit, into the adjacent engine room I might be able to squeeze an actual full size bathtub into the space. This would of course serve as a shower tub as well, so we would have the best of both worlds. But I would still have to do something about the water heating capacity.
Then I started thinking out of square.
I have a hot-tub at my home in Orlando, Florida, where I always enjoy a good hot soak, especially after a day of back-aching work on the boat. The therapeutic benefits of a hot soak have been known ever since man first discovered hot springs. If you suffer aches and pains after physical work, there is nothing finer than to immerse yourself in a nice hot bath, and if this happens to also have invigorating massaging jets, so much the better.
This had me thinking: what if I could convert a bathtub into a hot-tub on the boat, and enjoy the same relaxation? Power boats of Britannia’s size and big catamarans often have full size bathtubs, but on a 45’ foot monohull..?
First I needed to find a bath that would fit, which had to be the type with a sloping back to conform to the shape of the hull. I went to see a local spa manufacturer and asked the salesman if they had ever fitted a hot-tub in a boat? His blank expression gave me my answer, but after explaining what I wanted he saw no reason why they couldn’t fit jets into one of their regular household baths. He showed me a beautiful dark blue acrylic molding with a sloping back, which could be fitted with any number of massaging jets. He explained that there would also have to be a blower motor to shoot water through the jets on demand, and a separate heater to maintain the water at about 102F degrees, but these could be mounted anywhere. The existing water heater could not be used, because it was to small and a hot-tub heater also needs a circulation pump, to keep the water flowing through the heater element and maintain the desired temperature.
This idea was starting to sound expensive.
I made a detailed drawing of their bath, then, back at the boat I started working out how much room would be available after removal of the existing tub. But there was really only one way to properly find out. Since I was going to pull the old bath out anyway I might as well do that first, then I would have an open area to measure accurately and consider which to do next—shower or hot-tub.
Like many jobs on a boat, removing the old tub turned out to be very much easier said than done. I thought it would just be a simple matter of cutting the bath moulding out, but au contraire! It was an unbelievable monolithic structure, with two thicknesses of 3/4” inch marine plywood all round, sandwiched between layers of glassfibre and resin, all moulded into the side of the hull and bulkheads! It had to be hacked and levered out, bit by bit, using a reciprocating saw, a die grinder, a large pry-bar and an even bigger hammer! The whole lot must have weighed something like 150 lbs and I imagined the boat coming up three inches on her marks! I wore out five heavy duty saw blades—and myself!
After three days of struggle and sweat the last piece finally went through the door, and the whole area was laid bare, down to the floorboards.
As everyone who works on boats knows, many projects often lead to others. My wife never liked the pint sized leaky old manual head next to the bath, with its exposed pipework. Anyway, it was in the way of working on the new bath, so I removed it and threw it away.
Back at the tub manufacturers I discussed possibilities—and price, and finally decided to bite-the-bullet and order the bath. I lay in the tub while they marked the position of ten adjustable jets, directed on my back, legs and side.
The bath makers didn’t have the type of heater I needed. All their baths went in houses, where the hot water heater had sufficient capacity to first fill the bath, then the heater just maintained the water at that temperature. I needed a heater which could heat 55 gallons fairly quickly from cold. I found this at Acura Spa Systems, Riverside, California, who were extremely helpful in matching up the correct heater for my application. I bought a 240 volt 5.5 kw heater with a built-in circulation pump and controls. https://www.acuraspa.com
I picked up the bath in my van, and it caused some strange looks from fellow boaters in our marina, as a friend and I wheeled a full size bathtub, with all sorts of pipes sticking out of it, down the dock, and humped it on to Britannia. I joked to one inquisitive fellow that I planned to install it in a big hole in the deck, and he didn’t seem to be too disbelieving.
I had to cut 1½” inches off the side flange of the bath to get it through the companionway doors into the saloon, then into the aft cabin and bathroom proper. The sloping back allowed the tub to fit close up to the hull, but I still had to cut 4” inches out of the engine room bulkhead, and relocate some of the equipment and pipes to make room for the heater.
Once in the bathroom the tub plonked down exactly where I had planned it—which was a great relief. I couldn’t resist then finding out what my new creation felt like.
The original bath drained into the bilge, but I didn’t like that idea. I plumbed the drain into an automatic shower sump in the engine room, below the level of the bath, so even though the actual bath was below waterline, water would self-drain from the bath and be pumped out through a vented loop in the hull, above the waterline. At the same time I installed some shiny new bath taps with a flexible wand to an adjustable shower head.
The bath makers had managed to fit the jets blower into the end of the bath, but I still had to install the actual water heater in the engine room, and plumb it into the bath. This was relatively easy using irrigation pipes from our local hardware store. However, the heater also needed electrical power. The boat’s single AC shore power cable was 120 volts, but a hot-tub heater needs 240 volts to raise ambient water temperature to 102F fairly quickly. I therefore had to install a second shore power cable, then, by combining two 120 volt inputs through a double pole contact breaker I obtained 240 volts. This heats a full bath from cold to 102F in less than an hour.
I fitted the bath controls on the side flange of the bath. The blower pump was air activated and the heater controls digital.
With the bath and heater installed it then took longer to ‘finish off’ the bathroom. I built a curved alcove at the end of the bath then glued blue vinyl tiles all round, and grouted them to form a splashproof wall when showering. A curtain and rail was installed along with a second dome light. I also fitted a light behind an oval glass picture I had found of a square-rigger, which I set into the alcove to create a nice effect.
For the new toilet I choose the electric ‘Elegance’ model by Raritan Engineering. This has a full size seat and fully automatic controls, a built-in macerator, along with a good reputation for reliability. I installed this next to the bath and encased all the pipes. I personally hate to see marine heads with exposed pipes and valves, when with a bit more effort they can usually be enclosed. It also makes the head easier to clean. Britannia is British registered, so I thought it fitting to install a “patriotic,” toilet seat I have had for a long time.
The finished result is a beautiful bathroom with a fully functional hot-tub, and a great relief to slip into the steaming hot water after a hard days graft on the boat. I even mounted a holder to carry my pint of Boddingtons Pub Ale.
Yes, it was an expensive modification, and slightly decadent, but it’s also absolutely fabulous!
Okay, so you don’t have room for a bath in your boat’s head bathroom, but what about under a bunk, and when not in use it could be used for storage? Or then again, you could just cut a big hole in the deck…
I don’t expect to be able to use the bath anywhere other than in a marina, where the boat hardly moves. Trying to have a bath at anchor could be interesting, when a passing motor boat causes their usual massive wake...