Air conditioning on a live aboard

[skipmac]

One thing that was mentioned a couple of times that I think bears emphasizing, putting up an awning will dramatically reduce the temp inside the boat and make any air conditioning much more effective.

[stormalong]

I had a Mermaid 16,500 BTU unit in my 44 ft. boat when I lived aboard in Washington DC and Annapolis. It had reverse cycle which I would recommend for the cool season. It is the largest unit available that can run on 110V. It worked quite well, even on one of the hottest summers in DC history. It was over 100 degrees for something like 30 days straight. I recon it saved my life.

I also added a second 30 amp inlet for it - a necessity due to it's power draw.

[Cpt Mark]

On my 35' cat I calculated 16,000 btus were needed which I ordered through Amazon. Later when talking to the factory rep he thought 16K was too small. He was right. The lower staterooms are awesome during the day but the main salon is still way too warm. I'll add a sunshade and that will help a lot. Just put up the silver bubblewrap covers inside to reflect the heat back outside. One thing I didn't realize was you can't use them in waters less than 37 degrees. I was so excited to have central heat this winter. 1st run, flipped the switch and magically heat poured out. Awesome. 20 minutes later I heard a strange sound and watched as the water exhaust completely froze solid! It was 2.5 months before I got to use my heater. Life on the Columbia River.

My advice is to call the manufacturer and ask them.

[sailorboy1]

Originally Posted by skipmac

One thing that was mentioned a couple of times that I think bears emphasizing, putting up an awning will dramatically reduce the temp inside the boat and make any air conditioning much more effective.

I have 2 over the boat right now

My experience is that an awning and open hatches = the temperature your phone is going to say it is. So right now it's 88 degrees, with 68% humidity. which feels 96 degrees, outside.

I have the air conditioning running on the generator instead and it' 78 degrees for real inside.

[dakno]

I can tell you we have a 16k forward and a 12k in back. Insulater covers on all hatches, sun screens over all saloon windows, a boom tent, and a fore deck cover. This makes the boat comfortable, running both units.

[Rising Tide]

Practical Sailor just sent an email on calculating your AC needs. Search it up. You do not need to subscribe to receive their free emails.

[Mother1ship]

41'Morgan OI ketch, Corpus Hot Christi. Two cabins, two units, Marinair 16 Btu for aft cabin and 32 Btu for the salon and forward cabin.
Would not be without them, we have a 6kw genset when not plugged into dock. Just do it.

[contrail]

[QUOTE=zeehag; i will continue to use 5000 btu window unit in my formosa 41. works well. gets 120 here max, plus humidity, on occasion, so ac is a mandatory life saving piece of kit.
at anchor even in heat, the breezes are such ac is not needed. just place a shade screen over boat and open ports in bow for thru breezes.[/QUOTE]


120? Really, in Barra?

[ranger58sb]

Originally Posted by Keithward

How big are the units in most 40 ft boats and thinking that Pearson 424s would be a perfect example but other 40 foot boats what do you have for air-conditioning and how effective is it and what are your issues.

We have two 16K BTU units; one for saloon and galley, the other for staterooms and head. Maryland summers: hot and HUMID. ACs adequate, not extravagant.

-Chris

[Leo Ticheli]

We have one 16 BTU unit in our 40' boat in Pensacola, Florida. It keeps the boat acceptably cool, but certainly not as cool as our land home. We do not run the unit when we're away from the boat because I refuse to leave any seacocks open.

On our previous boat, a 28', I bought a stand-up room air conditioner and ran the exhaust hose through a replacement bottom washboard. We covered the exhaust hose with an insulation fabric and it worked very well. The condensed water goes out with the hot air exhaust. This is a cheap and easy method and you can stow the unit in a dock box when you go sailing. I'm considering doing this for our present boat so I can keep the boat cool and dry without opening a seacock.

Fair winds,
Leo

[GordMay]

Originally Posted by Rising Tide

Practical Sailor just sent an email on calculating your AC needs. Search it up. You do not need to subscribe to receive their free emails.

Some Practical Sailor Articles:

Calculating the Right Air Conditioner Size
➥ https://www.practical-sailor.com/iss...e_12606-1.html

Air Conditioning for Sailboats (Long Term Test)
➥
https://www.practical-sailor.com/iss...g_12433-1.html

More ➥ https://www.google.com/search?client...r+conditioning

[Simi 60]

We have no a/c and have never wanted it on our 60fter and have been onboard full time for 3 years at anchor with temps getting to around the 35c to 38c mark in summer (100f)

White roof, large overhangs, lots of cross ventilation works well except for zero wind days and then there is a noticeable difference but those days are rare.

As we head further north towards equatorial waters I reckon we'll need to look to a large 240v house type split system mounted on roof and plumbed into the wheelhouse hoping that spillover from that will cool our cabin aft of the wheelhouse and also drop down the stairs and cool the lower deck level.

[Quadrille in JB]

Redsky49
Why not discharge the condescent into the bilge?
My bilge (keel stub) always has ~1” of water in it and the condensate discharge is minimal.

[RaymondR]

Originally Posted by Quadrille in JB

Redsky49
Why not discharge the condescent into the bilge?
My bilge (keel stub) always has ~1” of water in it and the condensate discharge is minimal.

If one is already having humidity problems putting warm water into the bilge to evaporate is probably not a good idea. Also it's fresh water and encourages dry rot. Legionnaires disease petri dish? and smelly.

[transmitterdan]

Originally Posted by RaymondR

If one is already having humidity problems putting warm water into the bilge to evaporate is probably not a good idea. Also it's fresh water and encourages dry rot. Legionnaires disease petri dish? and smelly.

It all depends on boat design and construction materials. Condensate water is actually quite cold when it comes out of the AC condenser unit. Basically it is “pure” water since it is made the same way nature makes rain. If the AC unit itself is dirty that may be a different issue. And one should fix that as soon as possible. After all, the cool air you breath has been pumped through the wet condenser. If there is a possibility of Legionnaires then it exists there no matter where the condensates water goes.

Salt water in the bilge grows many critters but AC condensate not so much because it contains no nutrients. For keel stepped boats it’s impossible to keep the sump dry because rain will drip down inside the mast. AC condensate flushes that water out with a steady stream of clean water. It’s like a continuous car wash. Many boats drip condensate water into the bilge where it is sent overboard by a scavenger pump. I think there is no excess risk of health issues since condensate water is the same as rain water. In fact, one could argue that it helps keep the bilge clean.