Leeway
Leeway is the motion of an object to leeward due to the component of the wind vector perpendicular to the object's track. [1] The National Search and Rescue Supplement to the International Aeronautical and Maritime Search and Rescue Manual defines leeway as "the movement of a search object through water caused by winds blowing against exposed surfaces." [2] The resultant total motion taking into account the wind and current is the leeway drift of an object. Objects with greater exposure to each element will experience more leeway drift than ones with less exposure.
A navigator on a vessel must adjust the ordered course to compensate for the leeway drift and more importantly set and drift which takes into account the steering error.[1] Failure to make these adjustments during a voyage will yield poor navigational results. An object can either be active like a ship navigating through a waterway or a passive object like a liferaft. A passive object will also experience leeway drift. It is this drift that is of utmost importance to those involved in search and rescue upon the inland waterways and oceans.[3]
References
- ^ a b [Bowditch. (1995). The American Practical Navigator. Pub. No. 9. 1995 Edition. Defense Mapping Agency Hydrographic/Topographic Center. Bethesda, MD. p.116.
- ^ [National Search and Rescue Committee, (2000). "U.S. National Search and Rescue Supplement to the International Aeronautical and Maritime Search and Rescue Manual," Washington D.C.
- ^ [Allen. (2005). Leeway Divergence. Government Report prepared for the U.S. Department of Homeland Security. January 2005. CG-D-05-05. Retrieved. from http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA435435.