| 英文摘要 |
Boats, especially fishing boats, sailing in shallow water usually encounter tangling problem. Current Taiwanese fishing rafts/boats and many ring net fishing vessels all face this problem. The present project’s objective is to evaluate the possibility of installing pump jet on fishing vessels, including the comparison with traditional propeller on issues of tangling, efficiency, and life-cycle cost for typical Taiwanese fishing methods. New possible design of engine room and lines will also be considered. This study found that pump-jet almost avoid tangling problem；rim-driven propellers can easily clean tangled material by reversing operation or different speed, and can still operate even when ropelike material stuck with the blades. Both are better than traditional propellers. Without the consideration of indirect benefit of less tangling situations, the installation of pump jet on American style purse seine ships as subsidiary propulsion, small boat power, or maneuvering device (replacing rudder), will delay the balance of cost and benefit for only a slight level. The effect is smaller than the changing of fish price, and is about the same as the changing of fuel price. |