Replace Fridge with AC. What challenges to expect?

[wahoo33417]

Considering pulling out the 12v-only fridge and putting a 6,000 - 7,000 btu AC unit in its place. Looking to experienced brain trust here as to what challenges to expect.

Boat is an 2007 Sailfish. Fridge is an Isotherm Model 1049BA1CL0000. It works fine and appears to be in good shape, but I have no use for it. Boat stays on a storage rack, so no option of staying plugged in.

From what I can tell, there seems to be sufficient space for a small AC unit.

I'm assuming it will not be easy to run wires from the boat's control panel to the AC. If that proves problematic, I either sacrifice or tap into the 110v outlet on the forward edge of the Corian counter top. Or use those outlet wires as a 'pull-through' if I'm certain the two new sets of wires (one set for the outlet, one set for the AC) will make it through! My electrical prowess is that I can usually tell the positive from the negative terminal of a battery. This should be fun.

For the seawater pump, my intent is to sacrifice the overboard discharge through-hull just behind the aft berth. If I follow the plumbing hoses correctly, this through-hull is separate from the pick-up for the seawater input for the head. However, it doesn't look like this seacock has ever moved, nor has any intention of moving. As a retired marine biologist, I could never use the overboard discharge anyway.

I'm hoping that the same discharge for the sink can be used for the cooling water discharge for the AC.

The duct work, I'm hoping, shouldn't be too bad. The intake screen gets built into the new door covering the space. At least one cool air outlet should be able to exit facing the port side of the V-berth. Maybe another outlet can work its way beneath the steps and cool the aft berth.

The trade off in weight seems near enough to even.

So, what problems am I likely to encounter? I'm certain this will not be as simple as I've written it out. Any fatal flaws?

Tx, Rob

 

[Late Again Grady]

Just a thought...my ac unit is mounted behind my frig so space for what you want to do should not be a problem at all. You could still keep the frige if you like.

 

[mleads310]

Just to give you a heads up. The fridge also works without shore power! Don't get rid of that thing. Put the a/c where the factory had it originally.

 

[wahoo33417]

Thanks Keith and mleads. I did a search and read all the threads I could find of members either adding AC or replacing fridges. I really like the elegant solution of AMF of adding the AC behind the aft berth and on top of the waste tank. But I've got some bad discs in my neck that limit how much contorting I can do.

I do either day trips of fishing or snorkeling with the family so the fridge never gets a chance to get drinks cold. And when I'm doing sections of the Great Loop, I don't trust anything that puts that much load on the batteries when I'm that far from home. I even pull the 15 amp fuse just to make sure that little dial doesn't rotate to 'on' in bumpy seas!

So either way the fridge is going. Either to make space, which I need on my boat trips, or to make AC which would be really nice to have too.

This all started when Palm Beach County shut down all marinas and boat ramps due to the virus. fortunately my boat sits on a bottom rack so I can easily get to it. I was thinking of replacing the sink and faucet which have become a bit narly when I realized the fridge has to come out to get to them.

 

[Hookup1]

What about your water heater if you have one? I took mine out for storage. Under the v-bunks. Recently installed a bow thruster in it.

 

[wahoo33417]

Water heater is a good thought. That is another thing I've been meaning to get rid of. And now that you mention it, those wires could be the power supply to the AC, assuming they are correct gauge. I'd like to take some weight off the bow and open up that space for more lightweight items rather that put the weight of the AC in there, though.

 

[GWL139]

If you add an AC unit, you'll need to install a genset. The batteries and an inverter won't supply enough juice to run it.

 

[FloridaGirl]

Any updates on where you installed the AC? I just purchased a 2000 272 Sailfish and want to AC the cabin for weekends at Peanut Island or on the hook in Bahamas. I don't use the fridge at all and find the boxes in back keep stuff cool enough for a couple days, and so does my yeti cooler. I don't have shore power but purchased the EcoFlo Delta Lithium Battery Power Bank which would run a portable ac unit for a couple days before needing charging and will install a solar panel for that. Interested in what you ended up doing? Thanks!

 

[wahoo33417]

Floridagirl: I haven't done the AC install yet. But our recent trip through the Great Lakes has convinced me that AC install is a project for this winter. I gave the portable 5,000 BTU unit one more try, this time in the far north in July. Strapped in the aft berth, it was just barely adequate during the day in full sun in Michigan. At night it was plenty cold, but outside temps were in the 60s. It showed me that setup won't keep up in any truly warm climates.

When we came back from that trip, I asked our local dealer for a price to do AC install. They sub it out and quote came back at $13,000! Even the Grady dealership had to laugh at that one. Of course, the quote entailed gutting most of the cabin to run the AC supply and return vents from one end of the cabin to the other.

I've concluded that the best place for me to install is behind the rear panel in the aft berth. Prior to doing that, I will check and maybe replace some hoses leading to and from the holding tank. The AC install will essentially cut off access to the holding tank without removing the AC first. But since I'll be using the holding tank's overboard discharge seacock as the cooling water input for the AC, I'll have no electrical or moving parts associated with the holding tank to maintain.

I have already removed the hot water heater. And we replaced the fridge with a custom storage box. Both of those additional storage areas were nice to have on the Great Lakes trip.

Below is a pic of the portable 5,000 BTU AC as we had it for the Great Lakes trip. A total of three straps held it in place. Each strap was held by a U-bolt through-bolted with oversized washers. The exhaust ran through what was sold as a flush mount garbage container for boats. The cloth garbage liner helped make a seal around the AC exhaust hose. When the AC was running, I opened two 6" pie plates out on deck to let the AC's hot exhaust air out from below decks. One pie plate is on the aft face of the livewell and the other is on the aft face of the starboard cooler.

 

[wahoo33417]

Floridagirl: I forgot to say - Congrats on the purchase of the Sailfish! And good luck with her. You mentioned Peanut Island, so we must be neighbors. We store ours at New Port Cove, nearly across from Peanut Island.

Rob

 

[jmain]

$13k??? Wow. The only words I can think of to describe that have 4 letters in them. That is either someone who doesn't want the work or is trying to take advantage of you... or both.
I just installed a 9,000 BTU Reverse Cycle MermaidAir in a 1996 Marlin 30 for less than $3k. I put it behind the steps. It was a tight fit, but worth it, because I just didn't want to lose the storage space by putting it under the v-berth. The guys at Mermaid Air are great. They helped me on the price a little (they were more expensive than their competitors, and knew it), and Tom on the production team knows his stuff.
All in all, I still have a few loose ends to tie up, but it wasn't too bad. The only thing that was a 2 person job was fishing the wire from the AC panel down to the bilge. I did everything else solo.
If you have any specific questions, just let me know. I am happy to help.

 

[wahoo33417]

Jmain: Looks like a perfect fit!
I don't know the layout of the Marlin very well. But did you remove the fridge to gain this access? And (when you can) can you show some pics of how/where you placed your supply and return air vents?
Sorry to ask more of you after you provide a helpful post!

Tx, Rob

 

[jmain]

Rob,
No problem at all! I am happy to help.
Yes, that hole in the fiberglass is the cutout for the refrigerator. That is the only way to access that space in the Marlin. There is a bulkhead between it and the water heater just to the aft of it.
I have not yet cut the hole for the return vent, which will be in the side of the second step. I am trying to find an aluminum, stainless, or even plastic vent cover that is just the right size. I found one that is steel, but would only use that as a last resort, due to the inevitable rust problem from the SW FL air. Unfortunately, life got in the way, and I just haven't had time to finish that up.

The aft vent is the easy one. This is the port side of the aft berth. Just inches to the right of the water heater is the bulkhead that I mentioned above.


I am not sure I can adequately describe how the forward vent is routed, but here goes with a series of pictures.
This is the lower galley storage cabinet. The other side of the wall on the left is the space with the A/C and refrigerator. There was already a gap above the wall, so no cutting involved here. It is hard to tell from the picture, but the duct goes from the left (where the unit is) to the right and up through the top of the cabinet.


This is the top Galley storage cabinet/cubby hole. The picture is looking forward towards the bow. The duct comes up from the lower cabinet (see previous picture) and out through the front side of the cabinet. I drilled the bottom hole from the top down. It was actually relatively easy and the monkey fur (or whatever that stuff is called) cut surprisingly cleanly. I thought it was going to get shredded and fray badly, but it didn't.


And, here is my forward vent. I don't know if my hole saw was dull or too hot at this point, but it was like drilling through concrete. This one took probably 45 minutes to get through. There was a 120V outlet here (see the lower left of the picture). I could make it fit, but I don't think I am going to put it back, as there are two outlets on the other side of the "galley." I'll probably opt for putting the 12V reading light back, instead.


Finally, I haven't mounted the thermostat. The easiest place is right under the 12V plug in the picture above, but I am afraid that is too close to the vent and it will interfere with an accurate reading. I'll figure that out later.

Sorry, I don't think I have pictures of the water pump. It is in the rear of the bilge. The pickup is right next to the salt-water washdown pickup on the starboard side of the hull. Pulling the hose through the port rigging tube was surprisingly easy.

One other thing go note is that the unit has enough air flow to put a 3rd 4" vent. I may run one more to the helm area. It wouldn't make a bit of difference in the summer, but it may be nice to have a heater vent in the enclosure during the winter. More to come on that next winter.

I hope this helps. Just let me know if you have any other questions.

 

[wahoo33417]

JMain: Very nice job. Looks like you have good separation between your supply and return vents. And it looks like you did add a new overboard discharge outlet for the cooling water. I also see that my sailfish doesn't have near that much space in the area you're working in!

Something I'm pretty ignorant on: When you do place the return vent, how does it make an airtight connection to the AC unit's intake filter/screen? Does the AC unit have to be tight up against that vent or is there some ducting or insulated box that can connect the two? Sorry, but I just haven't seen a picture or a description of this part in my reading about installation.

Tx, Rob

 

[jmain]

JMain: Very nice job. Looks like you have good separation between your supply and return vents. And it looks like you did add a new overboard discharge outlet for the cooling water. I also see that my sailfish doesn't have near that much space in the area you're working in!

Something I'm pretty ignorant on: When you do place the return vent, how does it make an airtight connection to the AC unit's intake filter/screen? Does the AC unit have to be tight up against that vent or is there some ducting or insulated box that can connect the two? Sorry, but I just haven't seen a picture or a description of this part in my reading about installation.

Tx, Rob

Rob,
Yes, I added a new pickup and a new discharge. The discharge was super easy to do solo with a 1" hole saw and a tube of 3M 4200. The pickup really wasn't that bad either... I just hate drilling below the waterline!
Good question about the air return. There will be about a 1" to 2" gap between the fiberglass and the Return on the A/C unit. I am going to use strips of 1/2" foam board, caulk, and aluminum/foil tape to build a very short duct to keep the A/C from sucking in bilge air. I'll try to remember to send pictures, when I get to that. Until then, I am just leaving the refrigerator out. (We don't use it anyway, so I am considering leaving it out and building a cabinet out of that space.)
John

 

[wahoo33417]

Thanks, John. I'll have about two feet between the return grill and the AC unit. Would prefer to have that figured before I buy the AC. But now believing that I'll have to get the AC and trust that I'll come up with something, like you did. We also removed fridge and went with a custom cabinet.

Rob

 

[FloridaGirl]

Floridagirl: I forgot to say - Congrats on the purchase of the Sailfish! And good luck with her. You mentioned Peanut Island, so we must be neighbors. We store ours at New Port Cove, nearly across from Peanut Island.

Rob

We just got a slip at New Port Cove for ours! A good captain buddy of mine was able to get us in on a "dead" slip that actually works perfectly. I had another question about the AC for you....what do you think about a Casement Window AC unit installed in the Fridge space? Instead of a portable ac unit? Being they are tall instead of wide, I've found a couple with the perfect dimensions. Im having a tough time finding a portable unit short enough.. My concern is it venting into the Hull. I know there is a round hatch next to the fish box on that Port side that could be opened when in use to allow the heat out some. Do you think they throw off alot of heat that would potentially melt or damage anything in there? I've attached a pic of the fridge removed with dims, but I'm sure since you already changed that out, you are familiar with the space. Your thoughts are greatly appreciated!

 

[wahoo33417]

FloridaGirl: I do believe I’ve seen your boat. As recently as this morning when I was coming back from fishing.

I’m certainly no expert on casement ACs. But I would not think they would put out enough heat to melt electrical or water lines that run in that area. But from the fridge space, it is a circuitous path to get to that port side inspection plate. I'd look look for ways that heat could back up and seep it’s way back into the cabin. That could increase the load on your AC.

There are in-line blowers (fans) made to to assist long AC runs (not the kind that clear your bilge of gas fumes). These come in 4”-5” diameter lines. I'm wondering out loud if one of those could take the hot air and vent it to you inspection plate more effectively?

Two more thoughts: The casement ACs still drip condensate water as I understand it. Normally, this just drips outside. You would have to collect that water into one line and have a long run to the shower sump (preferably) or just to the forward bilge, since it’s likely not much water.

Second thought is that it looks like this unit will protrude out from your fridge space a fair bit. May want to put some pool noodles on the corners until your shins are used to the new obstacle!

One last thought and I'm not sure if it’s a good one or not. You could consider putting this in the rear panel of the rear berth. The heat would have a straight shot to two inspection plates. The big drawback is that the cold air circulation would be short circuited in that location. Although 8,000 BTUs is quite a bit for a Sailfish (Grady used 6,000), there would be some real inefficiencies there.

To get past that you'd have to secure some ducting to the cold air output vent of the the AC and run that to the main cabin. Even if you got it to the “window” in the stairs, coming out with some force, I think that would be good enough.

Ideally, you would split that duct, and have one run behind the stairs, under the sink, behind the the now gone fridge, and aimed at the port berth. At least on my boat, that is much easier said than done.

You would also have a much easier run to get the condensate water to the shower sump (or bilge) from the aft berth.

Take a good look at your sanitary lines running to and from the waste holding tank if you think you would consider the aft berth option. Once the AC is in place, access to replace these lines is pretty well cut off without moving the AC. So if the lines are showing their age, replace them as part of the AC project. I’m in the process of doing that now. If you have any really small friends that don't mind claustrophobic spaces, this this the time to buy them some beer.

Rob

 

[jmain]

Thanks, John. I'll have about two feet between the return grill and the AC unit. Would prefer to have that figured before I buy the AC. But now believing that I'll have to get the AC and trust that I'll come up with something, like you did. We also removed fridge and went with a custom cabinet.

Rob

Rob, I hear you on wanting to have it figured out beforehand! I could have done it in probably half the time, if I did, but I knew better. I have done way too many boat projects in the past to think that it would go according to plan!
It depends on how the unit (in particular the intake) lines up with the hole in the fiberglass for the grill. You could build something with foil or plastic ductwork. Or, you could build something out of 1/2" foam board and foil tape. (As was recommended for my situation by the folks at Mermaid Air.)
Let me know how the project goes. And, I am happy to help if there are any questions that I can answer!

 

[ttles714]

What am i missing here ???? Why not install the AC ( Mermaid as described) in the area behind the steps and keep the fridge ????