At-sea Towing Experiment Using Patrol Boats

抄録

There have been many marine accidents around Japan Recently. About 270 ships have actually been towed by the patrol boats in 1991. The towing operation is a very important role in the rescue mission of the patrol boats of Maritime Safety Agency in Japan. Maritime Safety Agency carried out the preparatory towing experiment using patrol boats first in the calm sea. After investigating the procedures of experiment, Full-scale measurement during towing has been carried out using 3 patrol boats offshore of Chiba prefecture. The main purpose of at-sea experiment is the estimation of towing force and the maneuverability in wind and waves. The following remarks have been demonstrated in this experiment. The average towing force during towing using synthetic fiber ropes agreed well with the estimation. However, the estimation of the extreme towline tension is quite important under rough sea conditions. The Characteristics of the turning toward the windward direction of the towed ship have to be understood during towing especially in the case of towing of PCC. The standard estimation of 1 ton per 100 PS decreases drastically in waves.