His Swedish Majesty's Ship
His Swedish Majesty's Ship or Hans Svenska Majestäts Skepp abbreviated H.S.w.M.S. or H.S.w.M. Ship, is the ship prefix used for ships of the Swedish Navy (Svenska marinen) when the head of state is a male monarch. In English, this is sometimes used when abroad to differentiate Swedish vessels from those of the British Royal Navy.
In the Royal Swedish Navy, all vessels are given the prefix H.M.S. (Hans Majestäts Skepp or His Majesty's Ship). This is true for both surface and submarine vessels