Stern structure for internal rotation double-paddle ship

Abstract

The invention relates to a stern structure for an internal rotation double-paddle ship. The stern structure comprises a pair of small tail fins. In a vertical view, each small tail fin is arranged at a horizontal inclination angle from front to back towards the central axis of a hull, and a pair of supporting shafts in the small tail fins incline at the same angle. The small tail fins inclining inwards conform to the direction of a flow field of a stern, tail water flow separation is reduced, and therefore resistance is reduced. In addition, pre-rotational flow with the rotating direction opposite to that of paddles act on the paddles, so that the rear tail flow rotation of the paddles is weakened or eliminated, and the effects of tail flow energy loss reduction and propelling efficiency improvement are achieved. By the adoption of the stern structure, the tail flow field is effectively improved, the propeller exciting force is reduced, the propeller first-stage exciting force under designed draft is reduced to be below 1.5 kPa, and the ship comfort is improved; the structure is relatively simple, the structure and the size of a tail attaching body are not additionally arranged or changed, and optimization and implementation are better facilitated; and the economical efficiency and rapidness are better considered.

Description

technical field [0001] The invention relates to a stern structure of a ship, in particular to a stern structure of an internally rotating double-screw ship, and belongs to the technical field of stern structure design. Background technique [0002] Passenger ships (including ro-ro passenger ships and passenger and cargo ships) currently use sculls due to draft restrictions, maneuverability requirements, and international regulations for safe return to port. Propeller internal rotation is more efficient than external rotation, so if there is no special reason, the form of internal rotation is used. [0003] The line shape of the large tail fin corresponding to the double propellers will cause the vibration of the propellers to cause the hull to vibrate, so it is basically no longer used. Currently, the more popular tail types are no tail fin + dual-axis bracket or small tail fin + single-axis bracket. The structure of the former is relatively simple, and it is often used on...

AI Technical Summary

Problems solved by technology

[0008] The technical problem to be solved by the present invention is: the stern structure of the existing internally rotating double-screw ship has a lot of room for improvement in terms of reducing resistance, improving efficiency, and improving the uniformity of wake flow. More bodies, more difficult to optimize

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