Measurement and Quantitative Evaluation of Skill Seaman's Sweeping Force of a "Ro", an Oriental Scull for "Wasen"

Abstract

In this study we experimented to clarify handling and sweeping method of a "Ro". Using a strain gage attached to the "Ro", we compared the skills of an "expert" seaman (A or A') with those of average skills, the middle (B) and those who have almost no experience (C). The results were as follows : 1) In the case of the "expert" seaman, the boat headed straight for the target point because push (Osae) and pull (Hikae) rate was relatively constant as was the tension on the "Haya-o". In addition the ship's pitch and roll was very small. 2) Under good sea conditions the average "Haya-o" pulling force was about 30% of each seaman's body weight. Comparing body weight the maximum value of "Haya-o" for the expert seaman was from 70%(A) to 120%(A'), and "Osae" was 1/3 or less than that of "Hikae". 3) For this study the "Ro" was positioned on the port quarter of the stern. It was found that although the power which moves the blade in the water depends on the position of the "Ro-gui", it was almost equal for "Osae" and "Hikae" when the boat was going straight.