Round bilge speedboat with constant wetted length

Abstract

The invention discloses a speed boat model with a constant wetted length and a round bilge. A curved surface of a boat body of the speed boat model is a closed curved surface with a fair space, and the closed curved surface with the fair space is generated on the basis of characteristics of a designed waterline, a midship longitudinal section line, an upper boundary line, a stern transverse section line, a midship transverse section line, a stern bottom oblique lift angle and a midship bottom oblique lift angle. The speed boat model has the advantages that the wetted length of the speed boat model is constant under the conditions of various speeds no matter how a sailing state of the speed boat model is changed; resistance of the speed boat model is greatly reduced as compared with resistance of the traditional speed boat with a round bilge when the speed boat model sails in drainage, transition and take-off states; resistance of the speed boat model is close to resistance of the traditional speed boat with the round bilge when the speed boat model sails in a gliding state, but the maneuverability, the seaworthiness and the seakeeping of the speed boat model are greatly improved, and the speed boat model can be used under sea conditions which are upgraded by (1-2) levels as compared with the traditional speed boat with the bilge; as the wetted length of the speed boat model constantly keeps unchanged, the speed boat model is favorable for theoretically analyzing and researching the performance of speed boats with round bilges by the aid of length Froude numbers.

Description

technical field [0001] The invention relates to a type of speedboat, in particular to a type of speedboat suitable for various types of speedboats with a Froude number in the range of 0.5 to 1.3 and capable of sailing normally under relatively high sea conditions, and belongs to the technical field of ship types. Background technique [0002] Speedboat is a kind of small boat that moves at high speed on the water surface. It is widely used in military and civilian fields, such as torpedo speedboat, missile speedboat, high-speed traffic boat, high-speed luxury yacht and so on. The shape design of the speedboat is related to the various performance indicators of the speedboat. A slight difference in the shape sometimes leads to a great difference in performance. Whether the boat shape is well designed or not is directly related to its sailing performance. A speedboat with a poor shape design may not even be able to sail normally. So how to design an excellent speedboat shape h...

AI Technical Summary

Problems solved by technology

When the traditional single-body round bilge speedboat sails in the low-speed displacement state, due to the smaller length-to-width ratio of the boat type, it has greater wave-making resistance than displacement ships; at the same time, because the traditional single-body round bilge speedboat takes off The wetted length will be significantly reduced, and the wetted aspect ratio will be greatly reduced. At this time, there is an obvious wave-making resistance peak, and the wave-making resistance is relatively large; When gliding on the water surface, the draft is reduced, the bow is raised, and the length of immersion is reduced, so that the contact surface area between the hull and the water is greatly reduced. Although the wave-making resistance is greatly reduced, at the same time there is The droplet resistance is reduced, and the longitudinal motion stability of the round bilge speedboat is greatly reduced due to the substantial reduction in the length of immersion. The substantial reduction of the bilge speedboat makes the maneuverability and seaworthiness of the round bilge speedboat worse; the seakeeping of the round bilge speedboat deteriorates due to the substantial reduction of the immersion length, thus limiting the range of operating conditions of the traditional round bilge speedboat

Different from the conventional displacement ship, the round bilge speedboat is a dynamic lift ship. When sailing, its navigation state will change with the change of speed, mainly the wetted length of the hull, the draft of the hull and the height of the hull. The change of the pitch angle brings inconvenience to analyze its various performances with the length Froude number

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