Stability indicator for marine vessel
US4647928A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 6, 1984 |
| Grant date | Mar 3, 1987 |
| Priority date | — |
| Expiry date | Feb 6, 2004 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB63B39/00
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A stability indicator for a marine vessel. The indicator continuously determines a GM value for the vessel equal to the square of the vessel's beam length times the square of the vessel's rolling constant divided by the square of the vessel's rolling period. The rolling period is determined by means of a gravity sensor whose output is an electrical signal corresponding to the instantaneous magnitude and direction of the roll angle. Electronic level adjustment and gain selection means are also provided, to compensate for the fact that the stability indicator may often be installed with the gravity sensor off-horizontal. The signal from the gravity sensor is input into a data processor that computes the rolling period by first analyzing the roll angle signal to establish a zero level and threshold levels above and below the zero level. The rolling period is then determined to be the time required for the roll angle to change from the positive threshold, to a value less than the negative threshold, and back to the positive threshold again. Successive rolling periods are averaged by means of a recursive filter, and the average rolling period is used to determine GM. In another embodime…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.