''Twenty years from now you will be more disappointed by the things you didn't do than by the ones you did. So throw off the bowlines, sail away from the safe harbor, catch the trade winds in your sails. Explore. Dream. Discover.'' – Mark Twain
Yesterday, we spent our first night at anchor in a very long time. I can’t explain how happy that made me.
We are anchored off the Key West harbor Marina where we’d been tethered to a dock for over a year. It’s a place I wanted to try since we got there, it’s a place we’ve been through innumerable times fishing in the dinghy and on the little Key West. We are at anchor now. All the hatches and ports on Pearl are open. We have a nice jazzy radio station on the the background, and we are sorting through the accumulated junk from life at a dock. Shortly Pearl will be lighter, tidier, and ready to put out.
Right now, she sitting comfortably in the wind and current. Tarpon are rolling around us. That’s what she was meant for. Bliss.
There’s a Southern phrase, “I’m fixing’ to …” that usually means “I am preparing to ….” Since it’s Spring, Lisa and I have been thinking about cruising again. In other words, we are “fixing’ to go cruising.”
Unfortunately, that phase has take on a whole new meaning for us. We’ve literally been fixing Pearl for the six weeks. We installed an air conditioner, we’ve replaced the batteries and charger, changed Pearl’s registration, replaced the fluxgate compass and recalibrated the autopilot, and now we are messing with the refrigeration system. The refrigeration system failed before we tried to leave the last time. Guess what? It did it again.
Harley chilling out on deck. He couldn’t be more relaxed.
Having determined that there should be no magical boxes on Pearl, we’ve dug into the refrigeration system. It’s both simple and interesting. It is has an air cooled compressor/heat exchanger (unlike our air conditioner which has a water cooled heat exchanger) and two cold plates, one each in the fridge and the freezer. The way the system works is the compressor and heat exchanger cool the refrigerant, pass it through the first cold plate in the freezer, then through a constant pressure valve, into the second cold plate, and back. The system is controlled by a thermostat on the cold plate in the fridge — it really doesn’t matter how cold the freezer gets as long as the fridge stays at temperature (about 35F). There are no fancy electronics here, just tables mapping temperature (remember Boyle’s Law?) and pressure and a mechanical control in a closed system.
There are two pressure readings that apply, one is the “low side” pressure for the cooled refrigerant where it exists the compressor/heat exchanger, and the “high side” for where it returns to it. The magic here is balancing the high and low sides with a combination of adding refrigerant and twiddling the constant pressure valve until it equalizes out. It’s not quite rocket science, but the same principles that apply in the combustion chamber and nozzle of a rocket engine apply here. Hmmm. Maybe it IS rocket science.
The base line pressure for the refrigerant on the low side should be 2-3 psi. The high side pressure depends on the ambient temperature.
Where we’ve been running into a problem is getting the pressure balanced between the high and the low sides. So far, this has been the result of a faulty constant pressure valve, and or some debris in the low pressure line when the valve was last replaced. Also, there may be a very small leak in the system that causes refrigerant loss whenever the freezer is defrosted. To find that we need to pressurize the system with Nitrogen to about 500 psi. I hope we can skip that for the moment.
Lisa and I don’t do well together when it’s too hot to sleep. We bicker. Tempers fray. Harley the dog tries to find a place to hide. None of that works well on a small boat.
A couple of summers ago we solved this problem by jerry rigging a window-type AC on deck to keep us cool. While cost effective and functional, the jerry-rigged solution is (as a friend of mine put it) ghetto-fabulous. It also makes taking Pearl out sailing a major production causing us to stay in rather than go sailing.
Having turned 50, I relented. I decided that I should follow Lisa’s advice and we should bite the bullet and install an self contained reverse cycle air conditioning system. The upside is that we can have air conditioned (both heating and cooling) comfort wherever we go — particularly if we add a a generator. The downside is the expense, installation aggravation, and loss of storage space.
Having finally consumed most of the stuff we provisioned for going to the Bahamas last year we agreed we could use the lose the roughly 2 cubic feet of space the the air conditioner and 4 cubic feet the ducting would consume. Note to self: don’t over provision. Also, we’ve been freeing space by tossing out stuff we (mostly I) thought was essential.
One can spend truly egregious amounts of money on an ACs and installation. Yes. There are such things as “bespoke” air conditioners — custom made units to fit in specific places in a boat — and it’s really easy to get sucked into thinking you need one. Having looked at the options, however, and friends who’d done their own installs, Lisa and I decided that we would purchase a kit and do the installation ourselves. It’s not rocket surgery, after all.
What we learned from out experience:
Measure several times, cut once.
Lay out every component and ensure that you have the space to do what you need to — e.g. connect fittings, hoses, and hose clamps — and leave extra hose and wire so that you can do maintenance.
Ensure there is a constant upward. flow of water from the through-hull to the filter, then the pump, and air conditioner — if you do this, you don’t need to worry about priming the system.
You don’t need to install a sump and possibly separate thru hull for draining condensation. A couple of vendors (Marvair and Mermaid) offer venturi pumps that attach to the discharge hose.
Double the time you think it will take to get anything done.
Also, consider taking yoga classes to prepare yourself for the unique positions in which you will likely need to pose yourself to install some of the components.
Fortunately for us, Beneteau offers the 373 with a factory installed air conditioning as an option. Beneteau’s Customer Service very helpfully provided us with the schematics and a parts specifications for the ACs they install, as well as pictures of someone else’s installation. While we did purchase several parts from Beneteau for the installation, we didn’t get all of them — in some cases because they just weren’t available.
As it turns out, the Dometic Marine Air 16000 BTU Retrofit Kit fits perfectly in the space mapped out. We tried a Webasto 16k BTU but despite the specs indicating it would fit, we just couldn’t wrangle the unit into place. We bought our system from West Marine, and avoided getting the install kit in favor of buying individual components. This ended up being less expensive than buying the “kit” and had better components — e.g. brass rather than plastic fittings.
The AC in place under the Port side settee. The grubby bilge is from the condensate buildup — which should be addressed by the Marvair Condensator.
The most demanding part of the installation was running the plumbing. While we had a “spare” through-hull fitting that we were able to use, getting the water filter, pressure pump, and air conditioner on a consistently increasing gradient was a bit of a challenge. We still need to fiddle around with this whenever the filter gets clogged.
Fortunately, Lisa is both small and flexible. Running the pipes and attaching the necessary hose clamps and fittings in tight spaces required some impressive contortions on her part. Regrettably, there is no photographic evidence of her feats as my picking up a camera would have resulted in “bad things” happening. I am not sure what the bad things are, but i prefer not to find out.
The most traumatic part of the install was cutting into Pearl’s cabinetry and drilling a hole in her hull. With the right tool, anything is possible. We ended up getting a Rigid Multi-Tool from Home Depot for cutting the holes for the return air vent, ducting, and the thermostat/control head. The multi-tool was far easier and more precise and manageable in the confined spaces we were working in than either a rotozip or a jig saw — we tried to use both. The mutl-tool was well worth the $65 cost. Prior to this, I thought they were completely pointless. For the vent into the salon, we needed a Milwaukee 5″ hole for which we used a hole saw. These tools, along with a nut drive for tightening the hose clams made the install quite manageable.
The other part of the story was hooking up the power. This wasn’t too bad. Instead of trying to patch into the existing wiring and adding a circuit breaker, we opted to run a completely seperate dedicated 30 amp circuit for the AC — complete with a Beneteau standard Merlin Gerin Circuit Breaker. There is nothing else on the circuit. This way, if we choose to run the AC while at anchor all we theoretically need to do is plug in the generator.
There is one other component we need to install. It’s a Venturi pump made by Dometic/Marvair that evacuates the condensation pan that currently drains into the bilge. While, once again, you can jerry rig a much less expensive solution using fish tank supplies, we figured the potential downsides out weighed the higher cost. Hopefully, once this is complete, we’ll be back to having a clean, dry bilge!
We love having our AC so far. It works much better than the ghetto fabulous cabin-top jerry rigged unit we had. It dries out the inside of the boat — which is nice — and keep the outside of the boat cleaner and less cluttered. Good call Lisa. Stay tuned for more.
