Customary to have near the companionway. Ours is under the garbage bin, held in place with Velcro. For coastal cruising, the two most important items in our bag are a waterproof handheld VHF and waterproof handheld GPS. Both with premium AA batteries installed. We have other signaling items (mirror, flares, etc) sunglasses, spare prescription glasses, hat, water, knife. Basically geared to a short time in the water or dinghy.

For multi day passages we keep ours under the games table (Stbd) with an easy release lashing around the table leg. (the table leg has a hook to hold the leg in place in case of knock down / inversion). We have to be able to find it in the dark...