Anti-Roll Stabilizing Tanks for Ships.

摘要

1,165,605. Ship stabilizers. JOHN J. McMULLEN ASSOCIATES Inc. 1 Feb., 1967 [7 Feb., 1966], No. 4831/67. Heading B7M. A ship stabilizer for minimizing rolling comprises an elongate tank 10, Fig. 1, which is orientated athwartships and contains a liquid in a free-surface condition, the motion of said liquid in response to rolling being retarded by a vertical plate 11 that is attached to the bottom of the tank and placed obliquely relative to the longitudinal sides of the tank so as to define therewith two convergent passages causing the liquid to flow around said plate, as indicated by arrows. The uppermost edge of the plate may be either adjacent the top of the tank, Fig. 2a (not shown), or below the static freesurface level of the liquid, Fig. 2b (not shown), so that during rolling of the ship some of the liquid flows across said edge. Alternatively, the edge aforesaid is inclined upwardly from each end of the plate, Fig. 2c (not shown), said free surface level being coincident with the outermost ends of said edge. In another embodiment, Fig. 4b, a non- return valve 40, or 42, is lodged between each end of the plate and the side wall situated at the greatest distance therefrom, each valve being constituted by a plurality of horizontal slats pivoted so that they permit flow of liquid in one direction only. The valves may be replaced by electrically-driven propellers (50), Fig. 7 (not shown), which operate either continuously at a constant speed to encourage flow of liquid around the plate in response to rolling of the ship or under the control of a gyroscope (30) that is sensitive to rolling motion so that the stabilizer is then of the activated-tank type. The propellers can be stopped when required by opening a switch (34). In a further embodiment, Fig. 5, holes 16 are provided in the plate 11 to permit some of the liquid to by-pass the ends of the plate, flow through these holes being regulated by pivotal shutters 15 that are operated by mechanism 13, 14, which is controlled by rollsensing means (not shown). Alternatively a plurality of holes (21), Fig. 6 (not shown), in said plate are controlled by horizontally-sliding shutters (17). The tank may have a profile in a horizontal cross-section which is that either a parallelogram, Fig. 3a (not shown), or a rectangle with rounded corners, Fig. 3b (not shown), the plate 11 being correspondingly arcuate at each of its ends with curved guide plates (11SP1/SP) situated adjacent said ends to promote the flow of liquid around the plate. The plate 11 may be pivotally mounted on a vertical shaft, or axle (12), Fig. 3c (not shown), so that its obliquity can be either adjusted to obtain optimum stabilization or varied under the control of a gyroscope (30) sensitive to rolling of the ship.