Are catamarans safer in rough seas?

Catamarans are not categorically safer in rough seas than monohulls — both are safe within their design parameters, but the failure modes differ. Catamarans don’t roll, are nearly impossible to capsize in normal charter conditions, and have redundant engines and hulls (a holed hull doesn’t sink the boat). Monohulls roll heavily but are self-righting if knocked down — a catamaran that does capsize stays inverted. Modern charter catamarans are extensively rated for offshore use and routinely cross oceans. In Caribbean charter waters, the safety question is essentially moot for either platform; in truly heavy offshore weather, a well-designed monohull and a well-designed catamaran are both fine, with different risks. See the catamaran fleet.