Marine Police will step up security of impounded ships after the disappearance since 1990 of three vessels held in judicial custody. Police said a watchman would be put on every detained vessel and regular checks carried out. To ensure a court order was obeyed, police would try to step up security measures regarding detained craft in Hong Kong, a department statement said. The latest disappearance was on May 18 at Tai Kok Tsui typhoon shelter, when a cargo ship, the Chao Shun, vanished with 13 crew members who were also its co-owners. News of the disappearance came during a High Court hearing last week on a multi-million dollar damages case against the ship's owners. Hon Lin Security was responsible for guarding all three ships and was expected to install a guard on board each ship. A company spokesman declined to comment as the case was under investigation. Operators who moor their boats at Tai Kok Tsui and Yau Ma Tei typhoon shelter areas said they sometimes spotted uniformed guards posted on seized vessels. But they said it would not be difficult for the detained vessels to sneak away from the area - where hundreds of ships are anchored - if security were not tightly imposed. 'There are many barges mooring in the area at night and the traffic is usually very busy in the morning between 6.30 am and 8 am when many vessels leave the sheltered area,' one operator said. 'It would be easy to take cover from these barges to sneak away if the security imposed on the detained ship was not tight.' Another operator said: 'It would also be easy to avoid checks by just covering the ship's name and number with paint.'