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Date: 10 July 2016. Moby-Cool a/c cover Tweak.


Note: This is the follow-up article regarding my quest for cool. Part One can be found in Air Conditioning the article.

It's summertime and it is HOT. Blazing hot. Like many, Seaweed is on a tight budget. A couple years back I bought the least expensive 5,000 btu air conditioner I could find. There was a problem: It was ugly. The a/c unit was not attractive to my eyes. Installation looked ragged and not at all nautical. The solution came from a company called Moby-Cool.

Update: Circa June 2023. The current best option for a 5000btu air conditioner with mechanical controls is (in my opinion) the Rovsun. The thing is, these will run off an inverter, albeit for not a long time without running down the battery bank. In my opinion mechanical controls is a critical component for me.

Mine did run on my 1000 watt Aims square wave inverter. Aims inverters are available at http://theinverterstore.com

affiliate link→

Rovsun 5000BTU ac with mechanical controls

This is a Before picture.

My a/c unit was tucked into the bottom of the starboard side pilothouse door. Scrap 1/4" plywood covered the rest of the doorway. Though the a/c was affixed it looked shabby. Quite frankly I love having a cute boat. Though being cool is very important, other factors come into play as well.


The doorway installation had problems:

  1. The boat looked junky. She resembled something a boat bum would live on. I love my boat and aesthetics are important to my happiness quotient. I want Seaweed to look nice.

  2. Having an a/c unit positioned there blocked exit from the starboard side of the pilothouse.

    At first I had the a/c mounted in the forward cabin hatch. My bunk became an icebox. The rest of the boat was miserably hot. A huge box fan placed in the doorway to my cabin pulling cold air out did not work incidentally. Argh!

  3. Coming into docks I was restricted to port side landings. I tie up the boat from the pilothouse doorways. There are large cleats that I use for my mid-ship attachment.

    Side note: Boaters know that once you snug up a line at the middle of your boat the vessel is not going anywhere. It is a good way for soloists to have great control of the boat. Once you have that center line tight you are safe and secure.

  4. The wood over the rest of the door meant I had zero view.

  5. The inside of Seaweed was much darker. The bleakness got to me.

  6. I need to see out and that a/c unit installation prevented that.

  7. Plus it was ugly.


A friend told me about the air-conditioner cover he had seen advertised in Southwinds Magazine. I took a look at the photo and was intrigued. If I could put the air-conditioner on the roof of Seaweed she would look spiffy again. I wanted that Moby-Cool cover.

The first thing I did is make a phone call. (407-435-9733) Scott is the designer/builder and seller of the item. He is an interesting character, a former sailor and now a land cruiser.

The Moby-Cool a/c cover was just what I didn't know I needed!

I called, paid and had delivery of my custom sized package in about a week. You'll need to know the dimensions of your air-conditioner when you phone.

My Moby-Cool cover arrived in a flat box. The fiberglass panels are nice, fit together perfectly and the build quality is good. An instruction sheet comes in the box along with self-setting screws. Also included are foam window stripping and a custom cut piece of 2" thick foam. That thicker foam fits between the cover and the air-conditioner on three sides.

Although the box contained screws I opted to use my own stainless steel 1" nuts, bolts and washers. For the curious, size 6 fits the pre-drilled holes. Everything lines up perfectly.

Seaweed has exactly zero insulation. The fiberglass air-conditioner cover did not have any insulation either. Though the owner of Moby-Cool assured me that it would work well as is, I opted to do a bit of tweaking. I wanted to insulate the cover.



After much research I bought Duct Insulation from Home Depot. Though not the least expensive, it was the best value. This is a part of my continuing work towards improving the infrastructure of Seaweed. I'm glad I bought it.


Frost King Duct Insulation

This Duct Insulation is made by Frost King Duct Insulation. It has a very sticky backing that adheres well to the fiberglass Moby-Cool cover. $20 bought me a 15' roll.

The metal side is about triple the thickness of heavy duty aluminum foil we use for baking. You can cut it with scissors.

First though I needed to figure out how to cut the 15' length. I wanted to maximize the number of layers insulating my hood. Plus I was determined to use all of it for my project.

Frost King Duct Insulation foil and fiberglass
←affiliate link



Side Note: I also opted for Professional Grade Duct Tape,
 not the cheap stuff. That tape was $15 for a roll. Ouch!



These are my notes.

I have 15' to work with. That is 180" of material.

My sizing will probably be different than yours. I have a 5000 btu air-conditioner that uses just 455 watts of electricity. That means it will run off a Yamaha1000 whereas larger a/c's require bigger generators.

  • The two side panels are 25" long by 12" high

  • The center cover is 33" long by 20" wide

Because the top is 33" long and 20" wide I chose to put three 12" by 20" pieces of insulation crosswise on that panel. Fewer seams should mean less loss to air drafts.

Affiliate links for generators:


I had some leftover packing paper and used it to make my pattern.

First I cut out the curved side pieces. There were bits and bobs of insulation everywhere.

With sticky side up, this job had to be completed before bunk-time.

If you decide to follow in my wake so to speak, do not forget that the left and right side of the Moby-Cool cover are opposites. Thus, when you cut the insulating foam be sure to flip over your pattern for the opposite side.

As you can see in the previous photo the fiberglass sides have umph. They are not plain flat and boring. The design gives this solution a step above anything I could have created by myself. That it is fiberglass (sturdy/good quality) should mean a long-lasting product.

I do not mind (much!) spending money for value. I expect this cover to last.

I covered the cut-away portions from the curvature of the sides with the main foam insulation piece.

The Frost King product sticks well. Be careful of the edges though. They are sharp.

The flat top panel received three overlapping strips, each 12" by 20" laid crosswise.

Next we wanted to insure the stick-um would stay stuck. I had on hand a piece of Delrin two inches wide. My friend Edwin was a Big Help in putting it all together. He understands angles, and all sorts of other things too.

The Delrin is attached at the holes that hold the top to the sides. It secures the insulation.


Edwin was a Big Reason this job got finished and looks so well too. Putting it together is a two-person job. Edwin did me a great favor in helping. Thank you Edwin.

I really Really did not like the look of the a/c unit in the doorway.
It was a sore spot for me aesthetically so having help was wonderful.



Side Note: Scott is the designer of the Moby-Cool air-conditioner cover. He said that insulation is not required. Online his install shows a hatch opened. That would offer a level of separation between the outside heat and the inside air-conditioning.

Just because I opted to make this more complicated does not mean you must do so.

One of my many failings is that I over-think and complicate things. I can take a five minute chore and turn it into a three day project with ease!


In a day or so I will show you the finished result. I am very
 pleased. Seaweed once again looks like the spiffy little ship she is.

Edwin is doing some measurements for the final install aboard Seaweed. Isn't my cover pretty?!?

Life aboard Seaweed is progressing nicely. More and more my home is all I dreamed she would be those many years ago. Actually she's better than I imagined. Life is great afloat.

I am becoming the Queen of Decadence and loving it too!

I'd love to hear what you do to stay cool in the summertime.
And, are you living on the hook or at a dock with plenty of power?

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2016, 2023

Categories: Characters, Comfort, Gear, Locations,

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