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Turn a Cooler Into a Compartment

You say you have a cooler you’d rather use for stowing gear than chilling drinks? Here’s how you can add sufficient ventilation without ruining the structure.

Two adults in a white fishing boat proudly showing off crabs caught out on the water on a sunny day.

Photo: Lenny Rudow


  • Easy


  • Cooler
  • Stainless-steel louvered vents
  • Wooden tongue depressor
  • 3M 4200 Fast Cure adhesive/­sealant
  • Stainless-steel screws


  • About an hour hands-on plus overnight drying time


  • $100 to $200


  • Power drill, bits, and hole saw bit
  • Screwdriver

Coolers are great for more than merely hauling drinks and ice: They also make excellent seats and work well for stowing gear. Unfortunately, if you try stowing gear in a cooler that’s left aboard for longer than a day trip, everything inside will soon become peppered with mold and mildew. A lack of ventilation is the challenge, but that can be easily overcome with a few simple alterations.

1. Choose your cooler, recognizing that after this alteration it will no longer be suitable for holding ice.

The size and type of cooler you choose will be the biggest determining factor in the cost of this project. If you plan to use the cooler for seating, be sure it’s thick and rigid enough, but stay away from “super coolers” with thick, insulated sides, as they have minimal stowage space inside.

For this project, I used an Igloo Polar 120-quart cooler. It’s wide and rigid enough for two people to sit on and has sufficient space inside to stow four life jackets, a throw cushion, an ammo-box containing safety gear, a small first-aid kit, and some miscellaneous supplies. We found that 5-inch circular louvered vents fit perfectly in the thinnest area of the cooler’s sides, behind the swing handles. However, the ideal location and vent size will vary by cooler brand and size. As a general rule, remember that larger vents will allow for better airflow.


You can ­remove the cooler’s drain plug to increase ventilation even more.

2. Hold one vent in place, then mark the screw holes and the perimeter of the vent.

Drill out the screw holes with the appropriate-size drill bit and use a hole saw bit to drill out as large a vent hole as possible while allowing at least a half-inch of room between the vent hole and screw holes. Then repeat the process on the other side of the cooler

Young adult with a backwards ballcap, black rimmed glasses, gray shorts and white shirt at the front of a boat holding a fish.

The cooler works great as a seat and also stows all that loose gear that used to roll around on the deck. Photo: Lenny Rudow

3. Seal the foam.

This step is critically important; if you don’t completely seal the foam and sides, water intrusion may saturate the foam. Squeeze a large bead of 3M 4200 or a similarly strong sealant along the surface of the foam all the way around the hole. Then use the wood tongue depressor to spread the sealant all the way ­around the hole, completely sealing it.

Allow the cooler to sit overnight and give the sealant time to cure. Otherwise, when you press on the plastic sides of the cooler, flexing may cause the plastic to pull away from the sealant and create a gap between the cooler walls and foam.

Vent on the side of a white cooler providing airflow.

Adding 5-inch louvered vents to either side of a 120-quart cooler will provide enough airflow to prevent mold and mildew. Photo: Lenny Rudow

Large white 120-quart cooler storing a red life jacket, red paddle, red tool box and other supplies.

A 120-quart cooler is enough to hold all the safety gear for a 16-foot boat plus plenty of other supplies. The cooler works great as a seat and also stows all that loose gear that used to roll around on the deck. Photo: Lenny Rudow

4. Screw on the louvered vents using stainless-steel screws and a screwdriver.

Give the screws a dab of 4200 before driving them in, to seal up those holes as well.

Now it’s time to load that cooler up with gear. As you do so, be careful not to block the new vent holes with the cooler’s contents, which cuts airflow.

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Lenny Rudow

New Boats, Fishing & Electronics Editor, BoatUS Magazine

Top tech writer and accomplished sports fisherman, BoatUS Magazine Contributing Editor Lenny Rudow has written seven practical boating books, won 30 awards from Boating Writers International — many for his marine electronics articles – and two for excellence from the Outdoor Writers Association of America. He judges the NMMA Innovation Awards, and is Angler in Chief at FishTalk, his own Chesapeake-based publication. A great teacher and inspirational writer, Lenny hosts many of BoatUS Magazine’s very-popular how-to videos, which can be found on the BoatUS YouTube channel, or at