Close-in defence needs overlapping weapons, not a token pair

Warships designed around limited conflicts have often carried only one or two close-in weapon systems as the final barrier against a leaking missile or aircraft. The problem is what remains when the sole mount fails or one member of a pair is unavailable. A triangular arrangement with one weapon forward and two aft can give most approach angles overlapping coverage. If one mount is disabled, a modest course change can still bring another system onto the threat. Laboratory performance does not remove the effects of salt water, wear, power faults, or battle damage. Ordering critical defences in threes and fours is therefore an insurance policy that preserves a fighting arc when reality defeats the nominal specification.