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Legend 35 - Icebox Refrigeration Conversion

Discussion in 'Big Boats' started by walmsleyc, Mar 10, 2018. Add this thread to a FAQ

  1. walmsleyc


    Joined Feb 2, 2006
    358 posts, 15 likes
    Hunter Legend 35
    CN Kingston
    I'm in the process of installing refrigeration for my 1987 Hunter Legend 35. It's a big enough project and I've ended up tearing most of the galley apart to get at the icebox to correct/improve the insulation that I thought I'd post a thread in case it's helpful for others with the same boat (or any boat!).

    Some background:
    • I'm installing an Isotherm Self Pumping unit with an evaporator.
    • The icebox is quite large, about 8cf by my calculations
    • The shape of the icebox is totally wacked out. They decided to fill the entire available space (good), but contoured it around the hull, liner protrusions, followed the angled back of the settee, and all other manner of shapes and angles, all of which will cause a headache in future steps
    • The cooler is VERY deep. Very hard to reach the bottom without lying on the counter
    • The construction of the galley cabinetry around the icebox was clearly done in a way that was never intended to be taken apart. Not easy to take apart, and MANY hidden, inaccessible screws.
    From what little of the icebox I could see from previous inspection, I knew it needed attention in order to have a reasonably energy efficient result. Here's what I've found:
    • The icebox will NOT fit through the companion way, so work has to be done on the boat.
    • Insulation is sprayed on the outside of the inbox
    • Overall, the insulation is mostly 1" - 1.5" thick (too thin)
    • Almost all of it has detached from the icebox. This renders it almost useless as there is up to 1/4" gap between the insulation and the icebox on almost all sides. It will convect away the cold easily, but made worse by ...
    • The entire top ~2" of icebox has no insulation. They ground the foam away to be able to access the screws holding it to the underside of the counter
    • The top of the icebox has very little insulation,maybe less than 1"
    • They ground the daylights out of the insulation to make it fit. Maybe necessary in a few tight spots, but other places they did this, there was lots of room.
    • The top lid has no proper air seals
    • The icebox has a drain. I had previously added a hose with a trap to prevent cold air from draining out of the icebox
    I now have the galley disassembled to the point where I can access all sides of the icebox. Doing so was a complete jigsaw puzzle of reverse engineering. There is a very specific order to disassembly, and it still involved getting a 2' long flex screwdriver to get at a few impossibly located blind screws holding things together. A good part of the cabinetry had cleats and screws that were 100% inaccessible. I had to keep a list of instructions so I can figure out how to re-assemble. I have ziploc baggies of screws all labeled as to their origins. I will re-design/build the cabinetry for easy of reassembly and of future disassembly. I can also add a little more space for insulation around the icebox too.

    I'm not 100% sure of my insulation plan yet. It will likely start with peeling the old insulation off. Once that's done I could re-spray new insulation (messy and tricky to get where it's needed) or adhere 2" (more in some places) insulation board (polyisocyanurate, still tricky because of the stupid shape of the ice box). I might consider trying to unscrew it from the counter so I can pull it out and get at it properly to apply the insulation.

    Here are a few picks of the galley with the icebox fully exposed:
    20180310_105440.jpg 20180310_105428.jpg 20180310_105424.jpg 20180310_105418.jpg

  2. RoyS


    Joined Jun 3, 2012
    321 posts, 68 likes
    Hunter 33
    US Bay Pointe, Quincy
    Looks like a difficult job. For what it is worth several companies make pourable foam insulation. These consist of two liquids that you quickly mix and then pour into an enclosed area. The chemicals react and then expand into a polyurethane foam insulation that fills the entire cavity. I have been considering using a product made by US Composites called 2 Part Expanding Urethane Foam. Although there are many similar products available, this one has some great qualities according to the advertisement. It produces a closed cell insulation that is resistant to water. Can be poured in multiple layers, each reaching full expansion in five minutes. In my case I will be drilling 3/4" holes in the top edge of the plywood surround to permit pouring the chemicals. The holes will be plugged with wood mushroom shaped plugs purchased from Widgets. My original ice box was also deep to accommodate massive amounts of ice on the bottom. It would not be practical to stack food from the bottom to the top after converting to refrigeration. I have instead built two stackable "milk crates" that will be used to hold refrigerated items in an organized and retrievable form once my refrigeration system is installed. Good luck with your project.

  3. walmsleyc


    Joined Feb 2, 2006
    358 posts, 15 likes
    Hunter Legend 35
    CN Kingston
    I have considered "pour in" or "spray in" foam. But I think I have too many issue that would complicate that approach. It wouldn't necessarily solve the delamination of the original foam from the outside of the icebox, though it might expand enough to push the gap closed. I can't help but think that it expand down to the floor, and into bilge, floor boards, and wiring chases. Getting it to stick under the bottom, or on the side against the hull would also require some creative thinking in order to prevent it from going everywhere and popping apart all the cabinetry.


  4. walmsleyc


    Joined Feb 2, 2006
    358 posts, 15 likes
    Hunter Legend 35
    CN Kingston
    • Cabinetry all removed
    • All but the backside ( and parts of the bottom) are now exposed
    • factory sprayed on foam insulation removed
    • Removed most of the screw holding it to the underside of counter
    If you look at the pictures (below), you will see that there just two small areas where the foam actually bonded to the glass icebox tub. Removing the foam was easy as it wasn't attached except for those two small areas. In general, it was 1"-1.5" thick. Rarely would it be close to 2" thick, and often <= 1". I'm not sure why it didn't bond, perhaps the tub wasn't cured fully when they sprayed the foam? Anyone have thoughts on this? I will test whatever glue I use first to be sure it will stick.

    Looking at the pictures, they used an angle grinder to remove the foam near the screws that hold the tub to the counter, and made a mess of everything.

    I will need to do something creative to avoid air gaps around the tub. The tub has a cored constructions and thus the exterior surface dips down near corners and other transitions.

    I was thinking about removing the whole tub to work on it, but the screws that hold it to the underside of the counter on the backside against the hull are a) very stuff to undo, and virtually out of reach. I know I will be able to a better job of gluing the new insulation to the box if I can remove it. Still pondering this one.
    Without modification, I will be able to put 2" insulation on just about everywhere (one area under an angled hull liner support will have to be 1"). Maybe 30-40% can be boosted to 3"-4", so that's good.
    If I'm not able to remove the tub, then I will have a tricky, but doable effort in sticking new insulation to the back and undersides of the tub. As you can see, 3 of the side are totally accessible, and will be relatively easy to apply new insulation to.