↑"HSwMS" here stands for "Hans/Hennes Majestäts Skepp" - The prefix "HMS" is used in Sweden - the prefix "HSwMS" is used in international contexts to avoid confusion with ships of the British Royal Navy.
This article includes a list of ships with the same or similar names. If an internal link for a specific ship led you here, you may wish to change the link to point directly to the intended ship article, if one exists.