Okay! Uncle! UNCLE! I need AC

[Wayfarer]

So it's been a really hot summer in Upstate New York. I feel like it's been over 90 about 4 days a week since I got here. The fans aren't cutting it. The cool showers aren't cutting it. When It rains, I have to close the boat up to keep dry, and the heat and humidity are wretched. I'm tired of sweating all the time.

I need AC.

This boat apparently has never had AC, so an installation would be all new. I'm not sure the electrical system can handle the load. I only have a single 30 amp shore power service, and I assume that won't be enough. I think my 6 KW generator could handle it, but I don't know, and I don't want to run that all the time anyway. I like the idea of being able to run it with a soft start on the batteries, but I really don't know if that's something I can fit with my setup.

I need a yard or a service person or a wizard who knows this stuff. Do you have any recommendations for trustworthy and reasonable yards or persons that can do an install from scratch without too much rape?

What system would you install if you were starting with a blank canvas? Any other lessons you may have learned that I could benefit from?

Thank you!

 

[Ski in NC]

Your boat is bigger than mine, mine being 38'. But I have a 12kbtu in the salon and a 8kbtu unit in the fwd cabins. Both run fine on a single 30A cord or the 5kW gennie. In fact on one trip in S. fla we were tied to a private dock where all we had was a 15A extension cord. On that power could run one unit or the other. In the day we would run the salon unit. At night the cabin unit. This was late June in the keys and it was hot as BALLS! But we were comfortable.

You don't need so much AC to chill it down to 72F in each compartment on the hottest summer day. You just need to get the edge off for decent sleep.

I bet you can do it with a 30A cord. I did it with a 15A cord!!

 

[rslifkin]

I just replaced my salon unit with a 16k BTU webasto fcf platinum. Draws 14 amps including the pump when cooling in today's brutally hot weather, so you could manage it. Adding a second 30 amp shore hookup would be an option as well. Your generator is plenty big, so no concern there.

For the most part, in brutally hot weather, the key is finding places with shore power. 24/7 generator running doesn't make sense, and it takes a lot of solar and batteries to run an ac that way.

You'll probably have to get hauled to put in an intake thru hull unless you have somewhere you can draw water from already in place. The rest of the install isn't too hard if you've got space to add another breaker in the panel and a place to mount the ac unit. Adding a second shore power inlet wouldn't be a lot of extra work either.

Cooling capacity wise, I've got a 16k and 2x 10k units. The 16k alone kept the salon and fwd stateroom at 73 all day today with no issue in 90 degrees, humid and sunny. That's probably only a little smaller than your interior. And I've got a lot of glass to absorb solar heat as well.

I'm happy to offer whatever advice I can. If you end up close enough I'd be happy to provide a pair of hands if needed as well. For some reason it's always nice to work on someone else's stuff instead of my own...

 

[Ski in NC]

well, boys. I makin him listen to Ted N. and i have him captive.
NOw whatcha gonna do

 

[Ski in NC]

My girl is listening to Ted Nugent and was sitting on my lap. Took over the keyboard. A little off topic....

 

[STB]

I have a 42' Europa Style Trawler home ported in the Tampa area. I have 30A service.

I've got a 9k unit for the lower cabins and a 9k unit for the salon and galley. I can run them both at the same time, I just have to give one or the other (usually the lower) a break when I run the hot water heater, stove, or over/microwave.

As far as cooling capacity, with the blinds drawn, I do fine. The lower unit cools that area without much trouble. The upper unit can't get it down to 72 on the hottest, most humid summer days, but does get it down to a dry 75, which is quite comfortable. If I had more capacity, I could open the blinds and let more solar load in, though.

If I were doing it again, I'd probably leave the 9k unit forward and move to a 12k-16k unit for the salon and galley to give it more headroom room. I'd still be able to run it at the same time as the other. And, I'd still have to turn it off for the stove, oven, or hot water heater.

I plan to put a start kit on them, one of these days, to see if that lets me let them run with the other stuff. It is the current kicking on that gets me, not the runnign current.

I like being 30A, even if it is a nuisance with things like this, because it gives me more choices for slips while keeping things simple.

 

[rgano]

Dave, I am not an AC expert, but I have installed a few and slept in a Holiday Inn Express last night. Before talking about marine air conditioners with the concomitant need for a seawater cooling pump installation and ducting, there is the idea of air-to-air units like the rooftop unit I have in my hardtop and the quick and cheap solutions available at your local big box store. A friend of mine had a twin engine trawler, oddly without an generator except for his Honda 2000 portable, with one of those portable ac household AC units with the intake and exhaust air tubes. He was happy until Hurricane Michael sank his tub. The first thing you need to decide about a marine unit is whether you want a 220/240 Volt unit or a 110 Volt unit. If you are already set up for a 30-Amp plug and the genny is set for 110, the decision is pretty well made for you. Get a 16 KBtu unit as that is about as big as you can get on 110 VAC. There are plenty of places where you can find the calculator to see what capacity you need. Maybe a pair of lesser units to cool say just your sleeping quarters and the saloon would do. I had a 16 KBtu unit which I could duct to the aft cabin or to the main cabin - it could send a bit to each, but on a hot day, it only cooled one or the other adequately (GB-42). I see where you mentioned something about a strain on your battery for starting? Well, this WILL NOT run on batteries - you are going be connected to shore power or on your generator to run enough ac to cool you off all day. Get a reverse cycle unit so you can also use it for heat if need be. Next question is split or self-contained unit. I had to have a professional to make the connection of the evaporator coil to the compressor of the 16 KBtu split unit I added to my trawler (total of two 16K units then, one self-contained, one split) because of the coolant (freon to us ignoramuses) filling routine, but I think there may be split units sold with some kind of quick connections allowing the layman to install one. Self-contained is much easier for the DIYer, assuming you have a spot for it to fit. I added a second 30-Amp shore power connection to the boat to support just the second 16K unit.

Now to starting. My brother just finished specing out his GB42 with a couple of Dometic units, and he was able to order their soft start micro-processors with them. For my 13.5 KBtu Dometic Penguin II rooftop unit (Penguin, gotta love that name) and my 10 KBtu Dometic Turbo marine unit I bought and installed the circuit board-only Easy Start from Micro-Air. Now I cannot hear when the little 3.5 KW Nextgen takes the loads - YES, I can run them both on that tiny thing because of the Easy Starts. So whatever you marine AC you might get, do yourself a favor and install either the Easy Start from Micro-Air or the Smart Start from Dometic. The big fat 35-dollar capacitors sold as soft starter kits DO NOT function like these up to several hundred dollar micro-processors; so don't get wound up in that idea.

 

[rgano]

I plan to put a start kit on them, one of these days, to see if that lets me let them run with the other stuff. It is the current kicking on that gets me, not the running current.

I like being 30A, even if it is a nuisance with things like this, because it gives me more choices for slips while keeping things simple.

BELIEVE me, the microprocessor soft start units really do work. See my note to Dave here. Not cheap.

 

[rslifkin]

Fwiw, the startup load on new webasto unit is definitely a bit less then the dometic turbo it replaced. It's not soft start, but the control box has a pile of big capacitors rather than just the one midsize one, so it's definitely a different setup. With a 6kw generator the startup surge will be no issue.

Thinking about it, I'd probably add a second 30a inlet and panel, as unless you have a 50a main on the current panel, you can't use the full output of your generator right now anyway unless your setup is fancier than I'm expecting in terms of inverter and such.

 

[boatpoker]

I feel your pain. We are in Oswego and just ran the Canal from the Hudson enroute to Port Credit, Ontario, delivering a GB46.

The heat has been devastating. We have run the three 16,000btu a/c's 24/7

The number of trees, construction debris and aquaculture has been amazing.

 

[Wayfarer]

well, boys. I makin him listen to Ted N. and i have him captive.
NOw whatcha gonna do

My girl is listening to Ted Nugent and was sitting on my lap. Took over the keyboard. A little off topic....

I was a little confused... hahaha. I thought I missed a joke somewhere. I think we can skip the court martial this time. Hello Ms. Ski!

Get a reverse cycle unit so you can also use it for heat if need be. Next question is split or self-contained unit. I had to have a professional to make the connection of the evaporator coil to the compressor of the 16 KBtu split unit I added to my trawler (total of two 16K units then, one self-contained, one split) because of the coolant (freon to us ignoramuses) filling routine, but I think there may be split units sold with some kind of quick connections allowing the layman to install one. Self-contained is much easier for the DIYer, assuming you have a spot for it to fit. I added a second 30-Amp shore power connection to the boat to support just the second 16K unit.

I'd definitely be open to adding a second 30 amp plug for the AC. I'd have no idea how to wire that all up, but I'm sure someone will take my money.

I have fairly giant battery bank at 1500 ah. Would it be possible to run the AC off of a 3kw inverter with a soft/easy start?

Also, since I already have a heating system... I don't really need reverse cycle, right? Would it save me money to get one that's cooling only?

Please forgive my ignorance. My brain has melted, and it hath wrought a stain most foul upon my settee.

 

[O C Diver]

I have three 12,000 btu units in my boat. But one of them only does the pilothouse. So, realistically, I air conditioning 2 staterooms, a hallway and a full head with separate shower, with one unit, and the saloon / galley with the other. So, I agree with Ski that you could probably get away with an 8K and a 12K btu AC units.

BUT, before you start, you need to figure the heat loading or insulation on both the saloon and cabin roofs. Insulation under a headliner makes all the difference in the world. Do you have a headliner? Is there insulation between it and the roof? How hot in the early afternoon does your ceiling get?

Another option is to air condition the saloon during the day and use a fan to push cool air into the stateroom after sundown. A single 16K to 20K BTU unit might do this very nicely provided you can close off the stateroom during the day.

I have done air conditioning on 2 boats and will be happy to give you some pointers, but you need to figure out the ceiling insulation, number of units, and if you're adding another 30 amp service, first.

Ted

 

[JohnS]

Our new 16k Dometic was choking for lack of cooling water, and as we had to come out to replace a depth sounder sending unit, I checked the through hill, found it was 1/2", and changed it out for a 3/4.
Redoing the pipe and hoses to 3/4, I found that the real problembwas that the PO had installed ghe sea strainer backwards, and I could never get it clean enough to work.
Also found that it was about to sink our boat, as the bowl was held on with only 2 of the 6 original screws, the others having broken off.
A new 3/4" Groco sea strainer fixed that.
We are cool, safe, and happier now.
JohnS

 

[Wayfarer]

So as far as the ceiling goes, the shell is something like 1/4" aluminum. The inner skin is painted plywood. There's some foam sandwiched in between, but I'm not actually sure how much. I'm thinking 1/2" or so. The ceiling doesn't get hot. The same can be said for the walls as well.

The windows get pretty warm though. The're tinted fairly darkly, and they get warm to the touch in direct sunlight. I would like to have some exterior sun shades made for them, but haven't yet.

As far as the number of units goes, I was thinking at least two, possibly three? I'd like a bigger one, maybe 16k for the main salon area. This will be hardest to cool, being the biggest area, with the most glass, and being directly over the engine room.

I was thinking maybe an 8k unit for the after stateroom, and possibly a second for the forward stateroom, hall, head, and shower.

The calculators I've used have suggested something like 36-42k BTUnits in total.

 

[Miz Trom]

I need a yard or a service person or a wizard who knows this stuff. Do you have any recommendations for trustworthy and reasonable yards or persons that can do an install from scratch

Back to Dave's original post, I think he's looking for a recommendation for a local a/c installer ASAP.


And Dave, you poor thing, I'm so sorry you are being annihilated by the heat wave. For the short term, are there any marinas nearby with covered slips? We've found that a roof makes a YUGE difference in how hot the boat gets, plus, you can leave windows open when it rains.


Another suggestion, an Air BnB for the short term? You need to get yourself cooled down for at least 36 hours, for the sake of your sanity.


I am bookmarking this thread for the excellent discussion on soft start.


And, Ski, how can I put this tactfully... did you know you can delete and edit posts for about 20-30 minutes after you create a post? This feature shows up at the bottom of my posts on my Windows internet-connecting machine. It took me a couple of years to notice it.


Cheers and stay safe,
Mrs. Trombley

 

[Comodave]

Easiest would be to add a section 30 amp inlet just for the A/Cs. A second option would be to convert to 50 amp 240 volt. You get way more power, not just 20 amps more but 40 amps more between the 2 phases. Don’t know if you need that much power or not.

Look for areas in the boat that you can possibly fit the A/C units first. When you have found all the places you could put the units then look for how to run the ducting. You want to supply the cool air up and have the returns low. I have put A/Cs in 4 different boats so far. Think outside the box on how to run the ductwork. Being in humid areas you will need insulated ductwork or it will sweat and you will have condensation which will cause mold over time.. you will need a sump pump for the condensation from the drip pans. Maybe your shower sump if you already have one but it need a down hill run to the sump or it will probably overflow and cause mold. You will need a pump or several pumps for the cooling water. They are not self priming so from the through hull it needs to be a continuous uphill run to the pump or you will always be messing with it to get it primed. Then you will need electrical run to the units.

It takes a while to plan it all out but once I had them planned and all the materials on hand usually it took a couple of days to complete the install. Hardest part is running the ductwork.

Good luck. Even if you have someone do the work these are some things to look for in the install.

 

[FF]

"The windows get pretty warm though. The're tinted fairly darkly, and they get warm to the touch in direct sunlight. I would like to have some exterior sun shades made for them, but haven't yet."

A couple of layers of news paper covering the dark glass might be a worthwhile experiment.

A priority relay would be an easy way to operate a large unit , the smaller unit could operate when the larger is off.

Personally I would not bother with a marine unit , thru hulls, water pumps etc.

I would select a Mitsubishi mini split , and forget the complexity and hassles of "marine" . Some are 120v.

It is done all over Euroland with no hassles.

 

[rslifkin]

Using just the aft 10k and salon 16k keeps my boat cool even with the tinted windows being hot to the touch (not covered) and the blinds open. Only time it really needs all 3 units is to cool the boat down on a very hot day when it's already heat soaked and the engines are hot. So 36k total should be plenty for you (accounting for cooling areas with doors closed). Even less would probably be fine, and would be easier to run all of the units on a 30 amp service (16k + 2x 10k is too much for a 30a line). On your boat, a 16k in the salon is probably right. 8k in each stateroom should be plenty, I think. Running all 3 on a 30 amp would still be pushing it, but you could always put 1 of the small units on the existing 30 amp inlet.

As far as reverse cycle, most come with it, but there are some cool-only units out there. They're not any cheaper though.

Adding a second 30 amp service is fairly easy. Just need a panel, a selector switch to select shore / gen, and another inlet on the boat, plus a little wiring. It can be done mostly independently of the existing shore power setup. Your generator will run 3, just watch what else you run at the same time. Converting to a 50A 125/250 inlet would also be an option. Then you'd have plenty of power for whatever you want to add to the boat (including enough AC to keep the boat at 65* in the tropics).

For condensation, your units will probably need to feed to a sump as Comodave said. From the pictures of your boat, I doubt you'll get them up high enough to gravity drain overboard (2 of mine are gravity drain, 1 dumps to the bilge which I need to change because it's too low in the boat).

 

[O C Diver]

Dave, you will get differing opinions on ducting, this is my experience:

Many people run into problems with the units icing up because of excess ducting. The ducting slows the flow of air down which results in the evaporator getting too cold and the condensation freezing. It is my experience (especially when adding AC to a boat without existing provisions for ducting) that locating the unit in a cabinet along a wall, with the discharge pointing up and angled to push the air across the ceiling of the room, gives the best performance. The saloon in my boat is setup this way. The unit is under a built in bench seat. The discharge comes up the back and discharges out the top. The insulated flexible duct is about 24" long and terminates in a box with a large vent with adjustable louvers. The louvers allow me to adjust the airflow to pass across the top of the ceiling and diffuse through out the room.

The second part that some people have problems with is too small a return. My saloon unit draws air through a louvered cabinet door where the louvers are 16" X 16". The smallest air passageway opening is 10" X 10". As a result of large vent and return sizes, there is more flow through the room on the highest fan setting. The room cools more evenly and the air conditioner runs more efficiently with a higher output as a result of more air flowing over the cooling coils. On most units, as you reach the target temperature, the fan speed automatically slows down. When the compressor starts cycling the fan is on the lowest setting for reduced noise. At this point, risk of the unit freezing up is essentially eliminated as the cycling compressor and constant airflow keeps ice from forming. I can't stress enough how important high airflow through the system is when the compressor is running continuously to initially cool a room down!

When I replaced the unit in my saloon, I eliminated some ducting in favor of a short large discharge, substantially increased the return size and reduced the unit size from 16K BTUs to 12K BTUs. The new system works better, cools the room faster, and is less of a load on the generator.

The final point is not to oversize the unit too much. Too large a unit has the compressor cycling more, which sounds good. Part of what makes air conditioning feel comfortable is that you're dehumidifying the room. The dehumidification only occurs when the compressor is running. A unit that short cycles can make the room feel damp for this reason. In a perfect sizing of the unit, you want it to run continuously on the hottest days during the hottest hours.

Ted

 

[rslifkin]

The final point is not to oversize the unit too much. Too large a unit has the compressor cycling more, which sounds good. Part of what makes air conditioning feel comfortable is that you're dehumidifying the room. The dehumidification only occurs when the compressor is running. A unit that short cycles can make the room feel damp for this reason. In a perfect sizing of the unit, you want it to run continuously on the hottest days during the hottest hours.

Agreed. Although on a boat if you have spaces that exchange air fairly well, you can shut one unit off to reduce capacity in less hot weather and avoid short cycling. I typically do this with my forward stateroom. The salon unit blows forward across the salon ceiling towards the door and I keep a fan in the forward stateroom pointed out the door down a bit lower. So it stays the same temperature as the salon and the forward unit can typically stay off unless the door is closed.

 

[OldDan1943]

Just my opinion. Always get a marine certified electrician to make this upgrade.
Put in an additional 30 amp service, put the A/Cs on the 2nd 30amp service and never worry again. The problem is running the duct work. That will take some plan and time.
Also you will need additional breakers on your main board for shore power or generator.
If you have an electric stove and HW heater and microwave, I suggest you put an amp meter in the galley so you can keep an eye on the electrical load of the house 30amp service. This is based upon my own experience..... I got tired of going fwd and resetting the house 30amp breaker, while cooking. I can do a bit of load shedding from the galley, briefly turn a couple burners off so I can run the microwave.

 

[caltexflanc]

Winter Harbor Marina-Boatyard in Brewerton NY has a very good reputation. Personally, I'd install the additional 30 amp (or convert to a single 50 amp/250v) so you don't have to screw with power management, and it gives you room to add other stuff as time goes by.

 

[rslifkin]

In that same area I've heard good things about Ess-Kay yards. Only personal experience is ordering a few generator parts from them though.

 

[Frosty]

A quick thing you can do that helps quite a bit is to get some Reflectix (Amazon, Home Depot, etc). It's puffy/foily stuff that comes on a roll. Cut some to fit your windows (on the inside) and it will really help with heat gain.

Some windows you can kind of tuck it into the frame with a friction fit; others I've just used a bit of blue tape. I still keep a couple of pieces to move to a super sunny window at times (stores flat).

It's vastly over-rated as actual insulation IMO, but it's great for reducing window heat gain, even if only temporarily. Standard roll is 24" wide and it comes in wider (depending on how tall your windows are). Just cuts with scissors, doesn't fray.

**********
On the AC, I don't know how interested you are in "innovating," but I found this article in Panbo interesting. (OTOH if you are roasting you want coolth NOW.)

https://www.panbo.com/dc-air-conditioning-comfort-on-the-water-no-generator-required/

**********
Now I'm going to sound like a total hack, but if there is a delay or you JUST NEED COOL AIR, consider a cheap window unit from HD, etc, as a temporary measure. They don't always have to go in a window. A buddy got desperate in a heat wave and just set one in a companionway (door type) with a curtain covering the rest of the opening. It worked (at a dock). 5,000 btu is $150 and they go up from there.

"Real" installed AC will be Sooooo Nice

 

[rgano]

......you need to figure out the ceiling insulation, number of units, and if you're adding another 30 amp service, first.

Ted

Big plus one on Ted's and others' insulation comments. I added 1.5 inches of T a before and after difference!

 

[Wayfarer]

Thanks for all of the input gang. It's all good stuff. It looks like I've got a bunch more research to do on the subject. The 12 volt options are definitely intriguing. I'd love to have the option to run it while at anchor, without needing the generizer.

With my work schedule, and everything else I have planned, it doesn't look like I'll be getting anything installed this summer. Looks like I'll be making do for the time being. I WILL have AC for next season, or my name isn't David Stupid Dangerous Fire Mozzarella Richmond.

I may actually try to bundle this project together with a couple of others, and put into a full service yard for a bit of a refit this fall/winter. I've got a list as long as Abe Lincoln's leg, and it would be good to get a bunch of stuff knocked out in one haul out.

 

[rslifkin]

To avoid intruding on your boating time, would it be possible to arrange to have at least 1 AC installed during your next work cycle?

 

[jeffnick]

I second the rooftop RV unit. Also the Micro Air EZ Start...and or the window unit. I have had great experience with them all on several boats.
https://72land-n-sea.blogspot.com/2016/07/staying-cool-aboard_21.html?m=1

 

[Comodave]

Before you go with an RV unit, get in an RV and listen to them, they are pretty loud. We live with them on our RV because that is how most RVs are made but they are loud. And it may decrease the value of your boat. I know I would not be happy buying a boat that had them in it.

 

[Bryant]

AC

So it's been a really hot summer in Upstate New York. I feel like it's been over 90 about 4 days a week since I got here. The fans aren't cutting it. The cool showers aren't cutting it. When It rains, I have to close the boat up to keep dry, and the heat and humidity are wretched. I'm tired of sweating all the time.

I need AC.

This boat apparently has never had AC, so an installation would be all new. I'm not sure the electrical system can handle the load. I only have a single 30 amp shore power service, and I assume that won't be enough. I think my 6 KW generator could handle it, but I don't know, and I don't want to run that all the time anyway. I like the idea of being able to run it with a soft start on the batteries, but I really don't know if that's something I can fit with my setup.

I need a yard or a service person or a wizard who knows this stuff. Do you have any recommendations for trustworthy and reasonable yards or persons that can do an install from scratch without too much rape?

What system would you install if you were starting with a blank canvas? Any other lessons you may have learned that I could benefit from?

Thank you!

I just ordered a new 16,000 BTU AC from Marineaire with remote control and digital thermostat. Delivered it was $1900. It cost me $500 to have it installed. It works great.