Advice on air conditioner for 1995 Beneteau Oceanis 440

[Caribe]

Hello:

I am considering the purchase of air conditioner unit (s) and wanted to get feedback and advice on proper sizing and where best to install it/them. I have the 4 cabin layout with 2 queen size cabins in the stern and 2 twin size cabins in the bow. I am especially interested in hearing from current owners of similar boats which have installed units. I understand that available space may be a constraint. I would be using the boat mostly in the Caribbean. It gets hot in the summer. I do not have a generator, so it would be used only when I am in marinas. I have 30 amp 120 volt service to the electrical panel. I have checked with one vendor and he suggested a 18K BTU for the main salon and the front cabins and a 12k BTU for the rear cabins. Let me know if you need more information. I will try and find a floor plan to post. Thank you in advanced.

[mayball]

Hello Caribe,

I am probably not the best responder to this thread, since my boat is much smaller than yours although I do have a Cruiseair installed in my aft cabin (sailboat). However, I am a refrigeration and air conditioning technician in Puerto Vallarta, Mexico, and was mechanical engineer in my former life.

The vendor would have had to be either familiar with your boat, or you gave him more information about the cubic footage of your spaces to be cooled. Normally you need a separate unit for each closable space to be air conditioned, unless you intend to leave the door open between the spaces (and then it will not work very well because the air handler would be in one space and the return air would have to be ducted from the other space). An exception to this rule would be a chiller unit which is probably too large for your application.

From the servicing standpoint it is nice to have all of your units in one place, with the refrigerant (suction and discharge) lines and the thermostat cable leading to air handlers in the spaces to be cooled. This allows the cooling water and the breaker panel to be easily combined in one place. The alternate installation is to installed "self contained" units in each space to be cooled and pipe (hose) the cooling water and overboard lines to each space. In either alternative, the condensate from the dehydration of the air must be either piped overboard or to the bilge.

This is just an overview. As you get further into your investigation, we in the forum can brainstorm from our experiences.

Don May
Fresco Marine
Refrigeration Service

[Caribe]

Don,
Thank you for your detailed reply. I found a floor layout of a 1993 sailboat which I believe to be the same as the 1995. I have uploaded it with this post. I have labeled with an "S" the storage area which are available at the moment. There are probably others that escape me as well. I labeled "Panel" where the electrical panel is right now. Hope this might help.

It would be nice to be able to shut the doors, as needed. I was told that the self contained units would make more sense for the size of boat. Thank you

[mayball]

Caribe,

So far, no response from other boaters. I agree, the self contained units look best for your application. It may be possible to use one unit for the forward cabins and one unit for the after cabins, and a third unit for the salon, using louvered vents in the bulkhead between cabins. Then the thermostat control could be located in the common area between the cabins. Then the occupants of the adjacent cabin would not be disturbed when adjusting the setting. I would suggest that you consult with the manufacturer on whether this would work. This would then be three units instead of five.

FYI, some manufacturers use a venturi in the sea water line to draw the condensate water into the line for disposal overboard.

Don

[a64pilot]

Your vendor sounds like he knows what he is talking about. I think though that you would need to add a second shore power cable and a second electrical bus and put the two AC units on that dedicated bus.
AC in the marina, will make it a whole different boat

[a64pilot]

I like the venturi idea to pull the evaporate condensate as opposed to draining it into the bilge, where can I get one?

[mayball]

a64pilot,
Check Mermaid's accessories:

Mermaid Condensator / Accessories / Marine Division / Home - Mermaid Manfucturing - Home of Mermaid Marine Air Conditioning & Medi-Kool Climate Controlled Drug Cabinets

Don

[richnjohn]

Sorry to ask a stinkpotter question but...
I have a trawler with a flybridgethat has loads of unused space. I've often wondered if it would make sense to put the A/C unit in the flybridge storage area to use the space (my engine room is cramped already). Ducting vents into the salon would be easy as you could just go trough the salon overhead. However, I've never seen the A/C located that high in a boat and assume there is a reason why. Is that because the heigth would be too much for the cooling water pump to pump it up to the flybridge?

[a64pilot]

As long as you ensure you get a pump that can pump that high, and I'm sure that would be real easy to do, I can't see any reasons not to put the Ac unit up there other than it's small weight, but several reasons to do it, one of them being put the noisemaker out of the living space

[btrayfors]

I agree that you will need a 2nd 30A AC line to run the two A/Cs. DO NOT attempt to run both of them on the same line. A 30A line cannot handle 30A continuous...more like 24A. And, the startup in-rush current from the A/C motors could well exceed the 30A, especially if both A/Cs were running.

In addition to the runtime amperage draw, don't forget to include the draw from the raw water/circulation pump(s) and from the blowers.

One possible setup: Use two identical 16.5 K BTU self-contained A/Cs, each with a plenum with three outlets. You'll likely need 4" diameter ducting, or larger. Don't skimp on size. Run one duct to outlets in each of the forward cabins and to the forward end of the main cabin. Run one duct to each of the aft cabins, with a third duct going to an outlet in the aft end of the main cabin.

Just a suggestion...

Bill

[mayball]

Although not overriding, there is a consideration when the condensing unit (compressor and condenser) is located a considerable vertical distance above the air handler: since the oil entrained in the gas must travel in the suction line back to the compressor, often the momentum in the oil is not sufficient to overcome gravity for this distance. Then the compressor starves of oil. This is solved by placing a U trap at intervals in the suction line to accumulate the oil and then blow it on up towards the compressor. People who have an mini split air conditioner on their roof sometimes learn the hard way about this consideration.

[Caribe]

Hello and thank you for the responses. I am glad that you made the point about the AC amps. I have been considering whether I should change the shore power 120 volts, 30 amps stern connector since the panel was originally wired for 220 volts. The boat was in Antigua in her early days. I am told that most other places except the US and its territories tend to have 220. The present marina has an option for 220 volts 50 amps.

What solutions would there be if I stay with the 120 volts 30 amps.? You mentioned 2 shore power cables.

In terms of brands for the self contained units, which ones would you recommend that are reliable, cost effective, and quiet?

[mayball]

With respect to brands of self contained units, of course I only see the units that are giving a problem. Although I have worked on most of them, I cannot say that one brand is more reliable than another. The key is owner maintenance, especially the sea water cooling circuit and the air filters.

Looking to the future, I would suggest you stay away from units using R-22 refrigerant, since it is going the way of R-12 and will soon not be available.

[Caribe]

Thank you all for the responses. I am going to tackle this project a bit later due to the costs.