A model experiment on the rubbish sucking ability of disk roters which are equipped on the sea surface cleaning ships was carried out, and following facts were found. Rubbish sucking ability of the disk rotaters is effective in the following cases. They are the case when there is a cover over the disk roters, thus preventing the splash of water, and also the case when there is a water conducting channel under the disk rotator.
　Water sucking ability generated by the rotation of the disk rotaters in the channel is found to be expressed by the function of rotation force of disk rotaters and sectional area of the channel.
　When the width of the channel is fixed (the sectional shape of the water flow in the channel is a rectangle), the maximam water sucking force of disk rotaters is found to be gained by lowering the channel at one third of the submerged depth of the channel.
　Another model experiment on the rubbish sucking ability of water jets shows that the sucking ability generated by using water jet is found to be more effective then the one by the rotation of the disk roters. This fact shows that the water jet may become the effective method of sucking rubbish for the sea surfase cleaning ship.