Development of an Emergency Trip System in Response to a Ride Control System FMEA

A focused FMEA for a high-speed monohull fitted with a RCS consisting of an automatic control system and a pair of transom mounted trim tabs was performed. Inadvertent deployment of a single trim tab was identified as possibly producing a hazardous effect.

Because operator action alone may not produce timely corrective action to inadvertent deployment of a single trim tab, a backup system was investigated using data obtained frommodel-scale tests. An Emergency Trip System (ETS) based upon transverse acceleration, roll, and yaw rate was developed that signals an emergency stow of the tabs. The algorithm was designed to be able to differentiate between normal vessel responses to aggressive maneuvers such as a hard over turn at maximum vessel speed and undesirable vessel responses to inadvertent operations of a trim tab.

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References

1. “Rules for Classification of High Speed, Light Craft and Naval Surface Craft, Det Norske Veritas, Part 0 Chapter 4 (includingrelevant amendments and corrections from the January 2006 version of Part 0 Chapter 1 Section 3), 2006.
2. “Recommended Procedures and Guidelines-Testing and Extrapolation Methods Maneuverability Free Running Model Tests,” published by the Maneuvering Committee of 24th ITTC, 2005.