Heat is used up in the process of turning a liquid into a gas; that’s why we feel cooler as our sweat evaporates.

B

For centuries, people have used this principle to cool things down. Nowadays, the most common examples are wearing a wet hat to feel cool, using a wet canvas-covered water bottle or simply hanging a beer bottle in a wet sock to cool it down in a breeze.

C

Ancient porous terracotta pots kept drinking water cold by letting it evaporate through the sides. A wet pottery wine cooler or a pot-in-pot zeer filled with wet sand does the same thing.

D

Drinks covered in a wet cloth can be kept cool in a bucket half-filled with water.

E

Pockets like this wick up moisture to chill small items
like cheese.

F

A crude air conditioner can be made from a thin sheet wicking up moisture. Any breeze from a wind sail scoop, or fan, will be cooled.

G

The bilge is normally the coolest place for storage. Drinks can be chilled when you’re at anchor by submerging them in a net for a while. Mind you, in some parts of the world seawater temperatures can be pretty warm!H

H

Portable cool boxes stay cool longer in an insulated locker under a foam mattress.

I

Put ice packs at the bottom of the box and fill any air spaces with an old towel.

J

Frozen square bottles of water are good, but reusable ice packs stay colder for longer.

K

Frozen food takes a few days to thaw out in a well-insulated box, but do label things so you don’t leave the lid off too long while searching.

L

First-aid instant cold packs will chill things for an hour or so—but may contain poisonous chemicals, so care needs to be taken around food.

M

Some bluewater sailors cope without a fridge by keeping cheese in olive oil and “bottling” cooked food with a pressure cooker.

Dick Everitt has sailed thousands of miles in various parts of the world. He has been an illustrator, journalist and engineer for more than 40 years.

September 2015