The ships are on guard/ protection duty to the nearby royal residences which also includes an exclusion zone along the seafront to all maritime vessels including jet skies and small boats.
From reading articles on the internet the naval presence is semi-permanent and ships in the Thai Navy operate on three month rotational basis. Around 300 naval personnel are involved and up to six warships. They are provisioned by local suppliers and may also be visited by refueling vessels returning to base at Sattahip (Chonburi Province) for any maintenance.
REG - TH
Chuang Class Water Ship
Built - Mahidol Adulyadej Naval Yard
L 33m W 6m
GT - 180
Year - 1966
Hua Hin, 21 July 2016