The effect of water-jet and teeth equipped with the Tokushun-maru No.1 at time of dredging the hard-packed sand was investigated and compared with the previous test result.
　The water-jet contributed obviously to an increase of the amount of soil dredged up. As for teeth, their shape and position of fitting were very important. They worked more effectively when fitted near to the heel of the head only.
　The propelling power during the dredging was measured directly by the FM-telemeter set and compared with the values calculated from angle of the CPP. Examination to the power distribution of the main engine revealed that the power consumption of the dredging pump and the jet pump was almost constant and then each ratio to the output of the main engine decreased as the ship speed increase. The properlling power naturally increased with the ship speed and the power distribution rate to that also but gradually increased.