Re: Super Maramu refrigeration insulation

Andrew Wilson

Hi Amelians,

Oliver on SV Vela Nautica made a couple of YouTube videos on his project to re-build his main freezer on his A54, he used custom made/sized panels:


Andrew Wilson
Future Amel Owner
Wellington, NZ

From: <> on behalf of Bill Kinney <cruisingconsulting@...>
Sent: Tuesday, 10 May 2022 2:39 pm
To: <>
Subject: Re: [AmelYachtOwners] Super Maramu refrigeration insulation

You can not cut the panels in any way, that was what made the design challenging. If the outer skin is punctured and the vacuum compromised, the remaining insulation capability is roughly equal to the same thickness of foam. At one time there were people who made custom sized panels, but those were expensive, and I wasn't able to find anyone still in that business.

The new box itself was made out of 4mm plywood with butt joints reinforced by epoxy fillets.  It's a simple technique that makes a surprisingly strong and rigid structure. All the wood was sealed with multiple coats of epoxy to make it (hopefully!) impervious to air and water vapor.

The insulating panels themselves I wrapped in the kind of 1/4" foam sheet used under the wood sill that sits on a building's foundation. This protected the surface of the panels from any mechanical damage, gave a little bit of "squish" to the fit, and also helped eliminate gaps where air could flow.

There were a few places in the design I couldn't close up with the fixed size panels that were available. Those were insulated with 4" of high quality foam sheet, any remaining gaps were filled with spray foam. It was one of the foam insulated places where the tubing and wires penetrate the wall.  I epoxied in a PVC pipe as a conduit to keep the insulation compartment air tight, and then filled that with spray foam after connecting everything.

I did everything I could think of to keep outside air from migrating into the insulation to avoid water condensation in the insulation.

The whole thing was painted with polyurethane paint to match the Amel interior gelcoat.

If I was doing it over, I'd probably use thinner plywood for the interior lining.  Conduction along the wood seems to be the biggest heat gain.  I am sure that there is some thin, stiff, tough honeycomb engineered material out there that would be even better, but I did not find any thin enough I was sure would work. Maybe a deeper dive into material for the aviation market would find something.

Bill Kinney
SM160, Harmonie
Simpson Bay, Sint Maarten

Join to automatically receive all group messages.