Up to the present, the Timber-Port-Loading come into operations by mankind power.
　But the latest trend is a tredency mechanization in accordance with an increase of labor efficiency.
　In this paper, we describe the experimental studies of some problems that is against mechanization in the Timber-Port-Loading.
　The experimental consitions are follows.
　Model scale : 1/4 Raking velocity : 5m/min
　Materials : 3 kinds of timbers (125, 200, 250φ))
　The experimental studies made a through investigation of some problems that are accumulating stages by a rake and power of rakes, some fundamental characteristic of the raking instrument and etc.
　We conclude from experiments and theoritical consideration described above : That is as follows.
　The accumulating power of rakes is proportion to volume of timbers.
　Even less power of rakes are capable of pile timbers in case their more variety in the specific gravity and diameters.