AC when away from the boat

[jgwinks]

The ac pumps are usually not self priming which means they have to be mounted below the water line. If the hose comes off the pump or any other below water connection, you're going to flood whether the pump is running or not. That said, hoses and connections are more likely to fail when the pump is running and under pressure. The ac unit will shut down if cooling water stops and it may or may not shut down the pump as well, but if the failure is below the water line it's all moot.
My boat has two ac units, one is completely below water. Any hose failure on that one will flood the boat. The other is up under the fly bridge, so at least half the connections are high and dry.

 

[Old Sea Dog]

My old Cal 2-27 had a molded keel with ballast in the fore end and about 18" in the bottom. That left about 24" bilge depth. Mounted pump and switch to 2" aluminum strap that lowered to bottom of keel. Also a manual in cockpit. My soon to be GB 36 has rule just forward of engine and manual at lower helm and salon entrance step. I would not leave a/c running when away from boat. Just have some ventilation.

 

[cardude01]

I am surprised there aren't more folks doing this. I brought it up a couple years ago and was flamed for suggesting fragile domestic equipment in a marine environment. While it makes sense that salt spray would create corrosion problems uncommon in land-based applications, the cost (low), safety (no through hulls) and comfort (AC without a generator running) benefits seem to be worth exploring.



My idea is to put the evaporator split in place of the current Webasto marine units, and the condenser split in the fly bridge seating with condenser air flow ducted from "inside" the seats out the rear of the seats. Dry as I can get it.

I’m also surprised more boats don’t set up a solar mini-split system. Silent AC while underway sounds so appealing to me. I experimented with the system installing it in my garage and it has worked out well. It’s a 12000 btu unit and cools off my two car uninsulated garage well. I used this unit because I also hooked it up to the grid for night time use, but they have total off grid units that will run off batteries as well.

https://www.hotspotenergy.com/solar-air-conditioner/

My boat really isn’t set up for this because of the lack of a good spot for the outside compressor, but I think most boats could make it work.

So the compressor/condenser on the fly bridge would be enclosed under a seat? You think you would have enough air flow? Interesting idea.e

 

[ksanders]

I would love to install mini split units in my boat.

The problem is where to mount the inside units.

Mini Split AC is the go to solution here in La Paz for both residential and business applications.

 

[cardude01]

I have a bookshelf in the PH that I think I could shoehorn an inside unit into, and maybe on a wall in the forward bedroom. Another problem is running the long line sets all the way forward. It’s definitely a challenge because the copper lines can’t make sharp corners very easily without kinking the tubes. At least I couldn’t do that well on my garage installation. I screwed up one line set.

At the last dock there was a defever type boat with the large covered rear cockpit area, and the owner fabbed up a wall on the starboard side that contained two mini split compressors. Pretty cool, but blocked a lot of his view.

 

[Steve1.0]

When I had my Morgan 452 ketch, the bilge was about 48" deep. I had my pumps (3) on 3/4 x 4" pt. decking planks. This made them "easier" (still a PITA) to pull up and service. One in the fwd bilge, one aft. On the fwd set-up, I had a secondary (oh sh*t!) pump with separate float switch/alarm, clamped just above above the primary. All were 2k gph. Never needed the os! pump fortunately, but it was nice to know it was there on long offshore passages.

 

[Steve1.0]

Back on topic, I leave my a/c units on and set to 80 when I'm away. It makes me nervous, but I inspect the system regularly when I clean the strainer basket.

The humidity and mildew potential in S. Florida is also insane.
If I'm away for any length of time, I hire someone (dock neighbor live aboard) to keep an eye on things.

 

[cardude01]

This thread currently seems to have three topics due to my scatter-brain mentality. ?

1. Leave AC on when away from boat? Consensus seems to be mostly no.

2. Have more than one bilge pump. Consensus seems overwhelmingly to be yes.

3. Feasibility of mini-split install on a boat. No consensus, but I like the idea. I think it makes good sense for AC in a pilothouse type boat for when underway running entirely on solar, since the line set run will be pretty short if compressor is located behind the PH somewhere.

 

[cardude01]

When I had my Morgan 452 ketch, the bilge was about 48" deep. I had my pumps (3) on 3/4 x 4" pt. decking planks. This made them "easier" (still a PITA) to pull up and service. One in the fwd bilge, one aft. On the fwd set-up, I had a secondary (oh sh*t!) pump with separate float switch/alarm, clamped just above above the primary. All were 2k gph. Never needed the os! pump fortunately, but it was nice to know it was there on long offshore passages.

Thanks for that description. Mine is also down in a “hole” so that’s probably why I have ignored it. [emoji51]

I do have a big 125v trash pump with a long hose to run out a porthole I could put down there in an emergency, if my generator starts that is.

 

[Steve1.0]

3. Feasibility of mini-split install on a boat. No consensus, but I like the idea. I think it makes good sense for AC in a pilothouse type boat for when underway running entirely on solar, since the line set run will be pretty short if compressor is located behind the PH somewhere.

Will you please post info on the split system you're considering.


edit, Never mind, just looked at previous post #33

 

[cardude01]

Will you please post info on the split system you're considering.


edit, Never mind, just looked at previous post #33

Just to be clear, the one I installed in the garage is the hybrid unit that is also hooked up to 230v. It seamlessly switches to AC when it’s cloudy and at night. This unit would work on a boat I guess if you wanted to tie it into you AC panel for use at the dock.

However, I think the totally DC unit makes more sense on a boat that already has enough solar and a good sized house battery bank that could run it a few hours at night if needed. Then if you are at the dock and want to run it all night I suppose you could with the battery charger running?

This is the DC only unit:

https://www.hotspotenergy.com/DC-air-conditioner/DC-AC-Complete-Systems.phpd

 

[Comodave]

They look really efficient but where do you put the outside unit? I guess if you have the room it might be a good solution. Not so much worried about corrosion because they are in houses by the ocean and you can replace it if it corrodes in 5 or 6 years.

 

[cardude01]

They look really efficient but where do you put the outside unit? I guess if you have the room it might be a good solution. Not so much worried about corrosion because they are in houses by the ocean and you can replace it if it corrodes in 5 or 6 years.

Seems like a pilothouse type boat like a Manatee would be a good candidate. Put the compressor on the rear deck next to the PH. Not sure where the air handler would go however.

 

[Comodave]

Yes, how to fit it in would be the issue. They are very quiet inside and efficient, just how to fit it in…

 

[rslifkin]

Fitting a mini split will be very boat-dependent. Some will be easy enough, others not so much. The typical water cooled marine A/Cs are definitely not used because they're better or more efficient (they're not), it's primarily for packaging reasons as you don't need to move enough air volume across the condenser, you only have to worry about the evap side of the system.

 

[Comodave]

A lot of houseboats use them but they have the room for the equipment to fit. Typical cruisers and trawlers not so much.

 

[ABfish]

Standard "humidity" mode on my Cruisairs runs the fan constantly, but only runs the A/C compressor for 30 minutes every 12 hours. The run time frequency can be adjusted.

I leave my air conditioners on Humidity mode whenever I'm away from the boat.

 

[boathealer]

Quality hoses and well maintained systems don't just break. My view is you're over-thinking it. Yeah, if you have no idea what your systems look like down below then something COULD happen.

*IF*, however, you have new, quality hoses and good clamps, and you inspect them and the rest of the system often, there is no reason not to leave the AC on.

We left ours running on all of our past boats. I knew those systems inside and out -- everything was rock solid and no way anything was going to "pop off".

Update your system components if needed, inspect them regularly, and sleep well.

JMHO....

 

[OldDan1943]

I have a 12K and a 16K. I leave the 16K running when I go to Atlanta for a couple of months each year. I turn it up to about 85F. So far, no problem.

 

[Pelican1987]

Given that I'm using my boat as a liveaboard I'm running the AC constantly. If you're worried about flooding your boat over the electric bill, replace the hoses and double clamp them.

 

[AquaDestiny]

I bought a portable A/C unit, ran the drain hose to the bilge and had my millenial mini me make me a 3D printed porthole adapter that I can swap out with the existing window for the exhaust. I'll take a picture when I get home. Pretty proud of it.

 

[Larry M]

On running the marine ACs when away from the boat, I think one of the considerations is the water quantity not if I’d loose a hose. Our home marina was on the Ortega River, off of the St John’s River in Jacksonville. The average depth of the marina was 4-9’ with lots of crap in the water particularly in the summer during seasonal thunderstorms. We were cleaning the raw water screens every 3-4 weeks and at least monthly I’d wake up at least once because the pump had lost its flow do to blockage.

 

[cardude01]

Larry last time I left my AC on multiple days at Ortega Landing the thru hull got clogged and shut the pump down. And for some reason ever since then that AC unit will no longer trigger the pump to run.

So I hear you on the crap floating around problem.

 

[AquaDestiny]

Here is the picture of my porthole “adapter”

 

[cardude01]

Here is the picture of my porthole “adapter”

That’s very slick

 

[psneeld]

I had bought one but didnt get to install it before I sold the boat....

It was a simple relay that cut off power to the AC pump and the trigger was the high water alarm system.

If I lost a hose, the bilge pumps would probably keep up but if they didn't, the high watsr alarm system would cut off power to the AC pump. The ACs whould shut diwn when they reached their high pressure limit.

Cant solve the strainer problem other than paying someone to clean it regularly.

 

[cardude01]

I had bought one but didnt get to install it before I sold the boat....

It was a simple relay that cut off power to the AC pump and the trigger was the high water alarm system.

If I lost a hose, the bilge pumps would probably keep up but if they didn't, the high watsr alarm system would cut off power to the AC pump. The ACs whould shut diwn when they reached their high pressure limit.

Cant solve the strainer problem other than paying someone to clean it regularly.

That sounds interesting. Where did you get this shut off system? Or did you build it ?

 

[BandB]

We leave ours on, but we do also have monitoring, both electronic including cameras and someone checking regularly.

 

[psneeld]

That sounds interesting. Where did you get this shut off system? Or did you build it ?

It was a solenoid I bought off amazon.Amazon.

OONO DPST 1NO 1NC 8Amp Power Relay Module, AC/DC 12V Control Voltage.

Trick is to find a relay that will not only work when the high water alarm triggers but will keep the power off until manually or electrically reset other than the float switch going back to normal off.

 

[cardude01]

When I got to the boat yesterday it was 103 inside according to the temp on the AC panel when I turned it on. Not sure how accurate that sensor is, but that seems a bit too hot!

Boat is in New Orleans.