A broach is an abrupt, involuntary change in a vessel's course, towards the wind, resulting from loss of directional control, when the vessel's rudder becomes ineffective. This can be caused by wind or wave action. A wind gust can heel (lean) a sailing vessel, lifting its rudder out of the water. Both power and sailing vessels can broach when wave action reduces the effectiveness of the rudder. This risk occurs when traveling in the same general direction as the waves are moving.
RS K6 Keelboat broaching, caused by wind action.
The loss of control from either cause usually leaves the vessel beam-on to the sea, and in more severe cases the rolling moment may cause a capsize.
An alternative meaning in the context of submarine operation is an unintended surfacing of a shallow-running submarine in a deep wave trough.[1]
Broaching caused by wind action may occur when a vessel is sailing away from the wind and its sails are suddenly overpowered by a gust of wind, causing it to heel excessively. Heeling alters the rudder's orientation, away from vertical, reducing the horizontal force which water can apply as it flows past the rudder. In extreme cases, heeling can raise the rudder out of the water. With loss of directional control, the vessel turns into the wind.[2] In the process, the vessel may heel close to horizontal and may capsize.[3] Such loss of control may be preceded by oscillations of the vessel's mast and course, as the person steering attempts to maintain control.[2]
Waves
Any vessel that is traveling in the same direction and close to the same speed as large waves (relative to the vessel) risks losing directional control when the stern is lifted in the water by an overtaking wave. Near the crest of a large wave, the orbital motion of the upper part of the wave is in the same direction as the vessel's course and can be close to the same speed as the vessel. When the orbital motion of the wave minimizes the velocity of the rudder through the surrounding water, the rudder loses effectiveness and steering is compromised. The vessel is likely to swing across the waves, roll to one side, and perhaps capsize. Naval architects have only recently started to produce workable mathematical models of broaching: the complexity is due to the non-linear nature of the phenomenon. What is well understood is that "wave riding" (traveling at the same speed as the waves) creates a substantial risk of broaching.[4] Wave action may contribute to a broach initiated by wind gusts.[2]
^Saunders, Harold E. (1965). "10: Definitions and nomenclature for Seakeeping". In Taggart, Robert (ed.). Hydrodynamics in ship design. Vol. 3. New York, NY: Society of Naval Architects and Marine Engineers. p. 160.
^ abcColgate, Steve (1979). Anne Madden (ed.). Oscillation and Rolling. More Sail Trim. Sail Books Inc. and Adlards Cole. p. 138.
^Bruce, Peter (2016). Heavy Weather Sailing (7th ed.). Bloomsbury. p. 248. ISBN9781472928207. Retrieved 21 June 2017.
broach, nautical, broach, abrupt, involuntary, change, vessel, course, towards, wind, resulting, from, loss, directional, control, when, vessel, rudder, becomes, ineffective, this, caused, wind, wave, action, wind, gust, heel, lean, sailing, vessel, lifting, r. A broach is an abrupt involuntary change in a vessel s course towards the wind resulting from loss of directional control when the vessel s rudder becomes ineffective This can be caused by wind or wave action A wind gust can heel lean a sailing vessel lifting its rudder out of the water Both power and sailing vessels can broach when wave action reduces the effectiveness of the rudder This risk occurs when traveling in the same general direction as the waves are moving RS K6 Keelboat broaching caused by wind action The loss of control from either cause usually leaves the vessel beam on to the sea and in more severe cases the rolling moment may cause a capsize An alternative meaning in the context of submarine operation is an unintended surfacing of a shallow running submarine in a deep wave trough 1 Contents 1 Causes 1 1 Wind 1 2 Waves 2 See also 3 References 3 1 Bibliography 4 External linksCauses EditWind Edit Broaching caused by wind action may occur when a vessel is sailing away from the wind and its sails are suddenly overpowered by a gust of wind causing it to heel excessively Heeling alters the rudder s orientation away from vertical reducing the horizontal force which water can apply as it flows past the rudder In extreme cases heeling can raise the rudder out of the water With loss of directional control the vessel turns into the wind 2 In the process the vessel may heel close to horizontal and may capsize 3 Such loss of control may be preceded by oscillations of the vessel s mast and course as the person steering attempts to maintain control 2 Waves Edit Any vessel that is traveling in the same direction and close to the same speed as large waves relative to the vessel risks losing directional control when the stern is lifted in the water by an overtaking wave Near the crest of a large wave the orbital motion of the upper part of the wave is in the same direction as the vessel s course and can be close to the same speed as the vessel When the orbital motion of the wave minimizes the velocity of the rudder through the surrounding water the rudder loses effectiveness and steering is compromised The vessel is likely to swing across the waves roll to one side and perhaps capsize Naval architects have only recently started to produce workable mathematical models of broaching the complexity is due to the non linear nature of the phenomenon What is well understood is that wave riding traveling at the same speed as the waves creates a substantial risk of broaching 4 Wave action may contribute to a broach initiated by wind gusts 2 See also Edit Transport portalGlossary of nautical termsReferences Edit Saunders Harold E 1965 10 Definitions and nomenclature for Seakeeping In Taggart Robert ed Hydrodynamics in ship design Vol 3 New York NY Society of Naval Architects and Marine Engineers p 160 a b c Colgate Steve 1979 Anne Madden ed Oscillation and Rolling More Sail Trim Sail Books Inc and Adlards Cole p 138 Bruce Peter 2016 Heavy Weather Sailing 7th ed Bloomsbury p 248 ISBN 9781472928207 Retrieved 21 June 2017 Rawson K J Tupper E C 1976 Basic Ship Theory Vol 2 Elsevier Science p 562 ISBN 9780080523385 Bibliography Edit Rousmaniere John October 1 1999 The Annapolis Book of Seamanship 3rd ed New York Simon amp Schuster ISBN 0684854201 ISBN 978 0684854205 Chapman Book of Piloting amp Seamanship various contributors Hearst Corporation 1999 Herreshoff Halsey consulting editor Mudie Colin 1983 The Sailor s Handbook Boston Little Brown and Company ISBN 0316546933 a href Template Cite book html title Template Cite book cite book a first1 has generic name help Seidman David March 24 2011 The Complete Sailor 2 ed Camden Me International Marine Ragged Mountain Press McGraw Hill ISBN 9780071749572 ISBN 978 0071749572 Jobson Gary 1987 Sailing Fundamentals New York Simon amp Schuster ISBN 0671605984 External links EditSailing yacht broaching 1 Tank test of power vessel broaching 2 Training material for power vessels 3 Retrieved from https en wikipedia org w index php title Broach nautical amp oldid 1145391748, wikipedia, wiki, book, books, library,
