How gun crews coped with heat until action stations

What did gun crews do for comfort when operating in hot climates?

They opened ports and used fans when possible, but action required the gun position to be closed and secured.

In hot climates, gun crews opened every port they safely could and some mountings had fans. Those measures made a confined weapon position more tolerable during ordinary operations. Once the ship began firing, however, the compartment had to be locked down. The short answer exposes the recurring shipboard trade-off between ventilation for the crew and protection during combat.