Improving Refrigerator Ventilation

Mar 20, 2007
Catalina 355 Kilmarnock, VA
Lousy sailing weather lately, so back to the project list. The fridge in the 309 is not very efficient, partly because it is set into a very tight space in the galley cabinetry with virtually no means to ventilate the hot air from the condenser in the rear (put your hand on the countertop above the fridge when it's running - almost too hot to touch). A recent issue of Catalina Mainsheet had an article from a 375 owner (the 375 has a similarly configured fridge/cabinet space), who cut a ventilation hole behind the fridge and covered it with a louvered grate. He found that It very much decreased the fridge run time and improved its cooling efficiency. Not sure what's on the other side of the fridge compartment bulkhead on the 375, but it seemed like a good solution for the 309 since the large cockpit locker is on the other side on our boats, and should be a good "reservoir" for the heated exhaust air.

It's a fairly straightforward modification, once you remove the fridge (which is the hard part). After removing the storage drawer and its frame under the fridge, there are 3 screws that can be accessed, attaching the wooden shelf that the fridge sits on to the fiberglass cabinet floor. After these are removed, the shelf slides forward (if it's never been previously removed, you may have to carefully saw/chisel out a small piece of the teak bulkhead trim on the starboard side to allow the shelf to slide past it - hardly noticeable unless you know it's there). Unplug the wiring from the control module, and the fridge can be lifted out (heavy!). I bought a non-rusting plastic 4"x12" floor register from Home Depot ($6-7), and cut a rectangular hole with a jigsaw, sized to give the register's flange a tight press fit. The hole is centered in the compartment, about 3" from the top since the compressor and evaporator are at the top of the fridge. This places the hole in a clear part of the bulkhead, to starboard of the trash can and behind the vented loop for the engine raw water system. I put the plastic register on the cockpit locker side of the bulkhead, so that the unfinished side is behind the fridge. Cleaned up, replaced the fridge and drawer unit, and done.

Although I haven't spent enough time on the boat to determine how much improvement in efficiency this will add, I did note a steady stream of warm air flowing into the cockpit locker through the vent, and the counter top is cooler to the touch. An added benefit is less added heat in the cabin for the AC to contend with at the dock.

Sorry for the lack of photos. Will get a few to add next trip.
Feb 21, 2013
Catalina 309 Newport NSW
A very worthwhile modification!
I have attached a picture of how I removed the fridge - note the screwdriver on the left holding the side panel out of the way and the screwdriver on the right used as a lever to pull out the fridge. Also attached is how I ventilated the back panel with a 2" hole saw.


Apr 6, 2009
2 309 Frog Motar Creek
Finally after much struggle got my fridge removed. Catalina factory dropped caulking from some other installed procedure. Used a saw and hammered it in between plywood and fiberglass shelf before unit slid out.