A/C installation

[mystery117]

I'm in the process of acquiring a 50' Beneteau for live aboard and cruising. It does not have A/C and we will require it. Looking for information from others who have had A/C installed on a larger sailboat - system used, installation concerns and issues to be aware of, whatever you may have learned. Thanks

 

[gettinthere]

Try to minimize the number of turns the ductwork has. It is amazing how much efficiency you loose with each bend in the ducts.

Consider the noise and vibration when siting units. They can get annoying.

I installed a venturi in the water discharge hose. The venturi creates a vacuum at a small nipple, you run a hose to the drain pan and all the condensate gets sucked up and pumped overboard with the cooling water. Works great. But do plumb a drain hose in case the suction hose gets clogged.

Is there a second 30 amp feed into the boat to handle the power consumption?

 

[Paul Mermelstein]

I have two friends with Beneteau 50s. Both boats have 3 AC units. One for the forward cabin, one for the salon, and one for the aft cabin (2 cabin model) or aft cabins (3 cabin model). You need to figure a BTU load for your boat and sailing climate.

 

[Gunni]

I have two systems, a 16,000 btu and a 12,000 btu. I rarely use more than the 16,000btu system in the sweltering heat of a Chesapeake summer. I use fans and open doors to move the air around.

Keep it at 2 systems, because that can be serviced by a single 30amp AC service. You want the other 30 amp service to feed your house bat charger, WH, and outlets. Maybe go with two 16,000 systems and good ducting.

The installation requires careful consideration of through-hull placement and configuration. There are ABYC standards for the installation. Don't let some jack-leg do the work.

 

[Eric M]

We have a 16k BTU system on our IP-35, it is sufficient even on the hottest day here in FL. I would not want to sleep in the same cabin as the unit. We keep the door between the unit and our cabin closed anytime we sleep with the unit running due to noise. I would strongly recommend a programable thermostat that allows you to set the unit to run either for a few hours a day, or to a particular humidity level such that you can keep the moisture out of the boat when you are away. As others have said, there is a lot of wiring, plumbing and ducting involved. You defintely need a highly competent installer.

 

[Lee Hadjiosif]

The first thing I would do is contact Beneteau factory and ask them for the schematic for installing the factory A/C units, including wiring routing BTUs and water pump installation location for the pump and controller. Usually one pump can be sized to serve all A/C units on board. Pay careful attention to the recommended duct size and routing. Someone will try to convince you that you don't need outlets in all cabins because it will be easier to install. Don't listen, (unless you don't need ac in that space) go with the factory schematic. Insulate all ducts. Don't let them tell you that you don't need it because it runs through conditioned space. You will be getting warm air out of the vent! Also you have to consider whether you will ever need heat when on the hard. If you do, get the resistance heat instead of the reverse cycle. In some units you are able to add auxiliary electric heat for when out of the water and when water is too cold for heat. Cruiseair and oceanbreezeac.com make good units. Good luck.
Lee

 

[Benny17441]

For a boat that size I would recommend at least two separate units. I would go for a 12K btu unit for the Captain's quarters and a 16K unit for the rest of the boat. The idea is that when at anchor you may run the smaller unit with a portable gas powered generator. A total of 28K btu are just about right for a 50' boat. You do not want too large a unit as they would not cycle frequently enough to remove humidity. A tent cover and hosing the deck periodically will allow the A/C units to work more efficiently in the Florida heat.