28 FBC AC Install

[h2ojetga]

Wanted to say hello to everyone as a new member and thank Capt. Patrick for helping me to register. New owner of a 1979 28 FBC and the first project is to add a self contained AC unit. Looking for advice on BTU capacity, sea water discharge location etc. I'm assuming that the best place to locate the unit would be the starboard storage locker. Any help from past experiences would be greatly appreciated.

In addition, I'm in the water cutting industry and have customers all over the Southeast and South Central US. If anyone needs any custom parts I'd be glad to help in any way.

Thanks
David

[MarkS]

Welcome David

[Tony Meola]

David

Welcome. We have a couple of members with 28's I am sure they will jump in.

You can also do a search of the forums and will find threads about AC units in the 31. That should give you a good idea of what is needed in BTU's. If I remember right, the southern members were close to 16,000 BTU's

[h2ojetga]

Thanks. I had 16K btu in mind. Just trying to confirm that a 1800W cont/2200W peak generator will start that size compressor. I'll search around for 31 owners.

[Skipper Dick]

David,

I am way down in Southwest Florida in the Fort Myers/Cape Coral area where it gets hot and muggy almost year around. I have a 12,000 BTU unit in my 28 and it will keep the interior nice and cool. Of course, you will need a generator if you want to use it off shore. I do not have a generator, so I can only use it when I have my shore power plugged in. I have never had to service it except replace the water pump once.

The unit is located under the forward seat of the table and is very easy to get to.

Dick

[CaptPatrick]

David,

1.8kw just ain't gonna' cut it for air conditioning... You need at least a 3.5kw to run 16k btu along with additional power loads. The best option, in my opinion, is manufactured by Next Gen. The 3.5kw is what I installed in Pat Hancock's B31 to run Mermaid 12k btu ac.





Hancock Generator Installation

Hancock AC Installation

[Harry Woods]

Bow weight is deadly on performance and economy. Move the unit aft under the dinette seats. Good luck with the new boat.
Harry

[Kevin]

I second Harry on the weight distribution being critical to boat performance. If you can mount the compressor against aft cabin bulkhead, that is the best for a couple reasons along with the boat performance. The raw water pump needs to be low as possible for ease of priming and that usually would be between the engines near all the thru hulls. Mounting the pump there will keep the raw water hose runs short and orderly to the compressor if it is located on the other side of the bulkhead in the cabin. Make sure you have a strainer with basket before the raw water pump. Keep the discharge thru hull close as possible to the compressor to keep it a clean install and not waste money on extra hose.
I have a very open cabin layout and only use one vent which is located less than two feet from the compressor/fan unit. 9000btu with the open cabin is more than plenty in south Florida. Stock cabin layout with multiple vents will need more btu like everyone said. I have a Yamaha 2000W inverter generator that will run it, but the ac compressor turning on requires full power of the generator and if it were in economy mode(idled down) it will not handle compressor start up loads.
I can post pictures if you would like to see them.

[h2ojetga]

Thanks for all the advice. I really appreciate it.

DA

[Tooeez]

Now that I am in Florida I am planning to install an a/c in my 28. I was looking at the Mermaid 9,000 btu unit. I am considering trying to get the unit behind the fridge on the port side--there is a huge empty space there, and it would help offset the weight on the starboard side (everybody likes to sit at the table while underway). I don't have a gen set--has anybody tried running a unit like this off a 2,000 watt inverter? It would be nice to keep the wife cool while trolling . . .

[Tony Meola]

Now that I am in Florida I am planning to install an a/c in my 28. I was looking at the Mermaid 9,000 btu unit. I am considering trying to get the unit behind the fridge on the port side--there is a huge empty space there, and it would help offset the weight on the starboard side (everybody likes to sit at the table while underway). I don't have a gen set--has anybody tried running a unit like this off a 2,000 watt inverter? It would be nice to keep the wife cool while trolling . . .

The inverter may not have the juice to start the compressor. It takes a lot to start them. I thought at one point, there was a unit on the market that was designed to run of an inverter. Not sure it is still around.

I did find this doing a search. Might help.

[Navatech]

Now that I am in Florida I am planning to install an a/c in my 28. I was looking at the Mermaid 9,000 btu unit. I am considering trying to get the unit behind the fridge on the port side--there is a huge empty space there, and it would help offset the weight on the starboard side (everybody likes to sit at the table while underway). I don't have a gen set--has anybody tried running a unit like this off a 2,000 watt inverter? It would be nice to keep the wife cool while trolling . . .

According to this the total running amps of this unit is 8 amps... Following the electrical formula of watt = amp (8) × volt (110) we get that your required wattage for the inverter to run this unit is a minimum of 880 watt and the required wattage for the inverter to start this unit is almost double that... So you SHOULD be able to run this unit of a 2,000 watt inverter... HOWEVER, you'll want to REALLY beef up your alternators and battery banks as this application will chew up your stored power like it's going out of fashion... Also, if you regularly run other stuff (e.g. fridge, microwave) you might want more inverter capacity...

Seriously, IMHO if you're thinking AC you've got to be thinking generator...

EDITED: I realized I made an error in my calculations so I recalculated... I also completely disregarded heating (electric or reverse cycle) as heating is rarely an issue in FL...

[Navatech]

I did find this doing a search. Might help.

Tony, I think you forgot to paste the link...

[h2ojetga]

tooeez,

you don't add those amperages up. once that compressor is running it will draw 8 amps. The start-up amperage is 1.8 X the running amperage so 14.4 amps. Heat running amps will be a little higher that AC running amps.

I think I'm going with a 9-10K btu unit and possibly even adding a hard start capacitor to bring down the compressor start-up amperage.

DA

[Tooeez]

The inverter I have is a Xantrex with a 3,000 watt surge capacity--according to the instructions it came with it is designed to handle the starting load for a fridge or freezer. I guess I won't know for sure until I hook it up. . . so far it has run everything I plugged in--vacuums, saws-all, circular saw, small air compressor, without any problem. I have a small a/c fridge in the galley that is on the inverter whenever we are away from the dock--of course that is a lot smaller than an a/c compressor.

Thank you to everyone for the feedback.

[Tony Meola]

http://www.offshoreonly.com/forums/gene ... erter.html

Nav

Thank You, I thought I attached the link. Hope this helps.

[bob lico]

i devoted quite a bit of time on my A/C and heat installation what i came up with is different.most of the big sport fishing boats beyond 60' have a enclosed air condition bridge so i installed a "hide away" 10,000 btu, high speed fan made by cruise air in the right side of the head vanity against main bulkhead ,return air is fur filled by way of slotted sliding door on vanity with complete access by sliding door open. this is also the best possible place for weight distribution .the 6" output goes to a distribution box located in back of galley refrigerator with two 4" outputs on straight to v-berth bulkhead the other under sole to back side of hanger locker with output facing salon. head door for return air is always open with sliding door in head.door has latch to keep in open position. amazing unit leaves room for shelf above unit on right side of vanity.

[Tooeez]

Tony, thanks for the link--it helps a lot! It seems that as long as the inverter can handle the starting load running the unit should be no problem.

Bob, thanks for the picture--she looks outstanding! I will check out that unit.

I will probably start this project around February--I will post how it goes.

[Kevin]

This is the location I installed the AC unit at. This is an old photo with the old unit that has since been replaced. As for water discharge location, mine is about 5 feet towards the bow on the same side. I had the hose and just used existing discharge location rather then putting in more holes. With a fresh install you can really put the discharge where you want.
With the vent so close to the fan motor pumping losses are very low so with the open cabin it gets chilly. It think at night I set the thermostat around 76 but the wind chill makes it feel about 70.

[Yannis]

Kevin,

Do you know if this "step" that shows in your pic ( the one that's under your couch and goes all the way forward - port and starboard) is structural, that is, can we cut it and get rid of it or we'll ...drown one day ? If I could cut it, it would have made my life SOOO much simpler, both during my couch building as well as the galley.
Thanks.

[Kevin]

Yannis,
My liner had been opened up prior to me buying the boat as you can see in photo above. Cut runs bow to aft in the top portion but does not go all the way to the corner where it goes to the floor. I would not remove any more than was already removed as I suspect there is some structural support as a whole. If you were to cut the corner where it goes from horizontal to vertical I am guessing you would have integrity issues with the floor sagging, but that is just a guess on my part. I am sure Pat or Bruce would know better as they have done extensive rebuilds far beyond what I have done. My boat seems to be holding up just fine with the mods that were done to it.

[Kevin]

Opened up a lot from factory design. 9000BTU handles it fine.

[Yannis]

Thanks Kevin,

I figured that too, I should rather leave the liner alone...

I like your open space mod; this past summer I invited a couple of friends and they slept in the fwd cabin. The guy at some point was looking for extra cushions and pillows, he said he needed them so he could level the bed surface as it was leaning aft; I thought so too, but hadn't thought by so much that extra pillows would be needed. With 2 people it's more convenient to put your legs forward I think. So I'm now thinking to add some wedges under the aft side of the cushions. Will this boat ever stop needing new things ? !!!!

[Tony Meola]

Yannis

A dear departed friend on his 31, put a removable insert into the V berth opening, so that the V berth while sleeping was now evened off and created a bigger bed. Just a suggestion.

[Yannis]

Tony thanks, but I don't seem to understand this. Perhaps if you could explain a bit more. Thanks.
In the 31 you may have to sleep athwartships to fit.

[JH_B28]

David,

I have a 10,000 btu on my B28 and it works pretty well with the temperatures we have in PR. I had to tint all the glass to keep the temps down during the day, but at night it can get quite chilly.

I'm currently redoing the whole boat and will probably go with Kevin's idea for the location of the A/C. It is perfect for many reasons as he said...weight distribution and the pump can be mounted close to the inlet seacock.


Regards,

George

[JH_B28]

Kevin,

Do you know if this "step" that shows in your pic ( the one that's under your couch and goes all the way forward - port and starboard) is structural, that is, can we cut it and get rid of it or we'll ...drown one day ? If I could cut it, it would have made my life SOOO much simpler, both during my couch building as well as the galley.
Thanks.

Yannis,

I cut a part of the liner "step" in the Head to gain a few more inches of floor space. Once I finished cutting, I gained about 4'' up to the stringer. To regain strength in the floor, we poured polyurethane foam under the floor between the hull and the liner and tabbed the liner to the stringer with 1708. The foam is to create a sort of "cushion" under the liner in case the hull flexes.

If you cut both steps, you would have to tab the whole floor to the hull. I don't think this would compromise the structural integrity of the hull but I'll leave that to the up to the pro's.


Regards,

G

[Yannis]

Thank you George,

I've been through the tough times where I had to decide what to do with this liner that was always in the way.
Now I'm done and I'm contemplating "what if" situations.
I'll start another thread with some structural issues though.

As far as the A/C, I agree that insulation plays a critical role. And our 28, and probably all other B's too, are not that well equipped. These windows, even closed, are as if they are open, and there's that door top hatch opening too!

[h2ojetga]

haven't been on in a while. Thanks again for all the advice.

DA