avril 22 2013
The term bowline, bowline comes from the English term, “heads or bow ties” that were used in the square sail boats to withstand the leeches of headsails when sailing to windward. The bowline is properly rope that pulls the luff of the sail to windward or leeward bow, so that when it follows the wind, it enters into the candle without making flaming.
Meanings, compounds and phrases
Position of the ship into the wind.
Punishment in warships was given to criminals, running alongside azotándoles rope passing through a ring secured to your body.
The junks with sails which folded in the galleys.
Bowline stick: the stick where they are envergadas gaff sails and other equally.
Bowline scarce: the position where the gear touches snugly even after, to follow a bearing.
Bowline in reverse: reverse strands, which are the windward and leeward tack and bowline.
Bowline long, frank, wide or open: Bowline position of ease, where the candles are the wind without it makes them flaming.
Running bowline: suffer the punishment of this name.
Aiming the bowlines: use these ropes to windward tesar leeches of the sails.
Air flow is generated around a candle (or any body immersed in a fluid in motion) causes an increase in speed of the points of the outer (convex) of the sail. In an incompressible fluid to a speed change corresponds to a change in pressure.
The pressure acts on the sail: sail imagining divided into many small pieces, and taking into account the contributions of the pressure acting on these small pieces both windward and leeward, we obtain the resultant force of the wind acting on the sail , called thrust.
It is the same principle that generates the thrust to the keel of the boat, on the wings of airplanes, bridges, etc.. In essence, rather than by the pressure generated on the windward side, the thrust is caused by depression generated in the lee side. The resulting thrust is perpendicular to the mean chord of the curved section of the sail (in first approximation).
The profile of a sail exposed to the wind divides the air flow into two segments. Due to the curvature of the sail in one of the two segments (windward) air circulates more slowly, because you must travels less “way”, while running along the outer surface of the sail, long way (leeward) increasing the speed accelerates.
The velocity difference causes, according to Bernoulli’s principle, the establishment of a pressure difference between the two sides of the sail. The pressure inside (windward) is greater than the outer side (downwind) and is manifested as a suction force spare sail, roughly perpendicular to the wind direction and thereby advancing the vessel.
This principle, combined with the use of the keel allows the boat moves in a straight line against the wind. Which would not be so in the absence of the keel as it creates a force on the water, “equal” in intensity, but opposite to the component perpendicular to the axis of the boat described without constructive use of this device keel, would only result without the possibility of having a windward or controlled direction.
When the mainsail is added presence of a jib (or genoa) therebetween establishing a complex interplay. The hypothesis that there is a bottleneck that increases the air velocity in the surface downwind of the mainsail must be considered erroneous. The fundamental interaction of both candles can be summarized in a transfer flow aft (apparent wind) acting on the headsail improving the ability of the boat to go upwind.
In the old ships with square sails, the bowline or “Borin” (bow-line) was a rope that allowed tighten the vertical edge of a sail block (called luff). Since this place was used to hunt the windward end of the square sail when the boat is “encircled” the wind, the term has become synonymous with this type of navigation and the “adjustment” of the candle optimal to do so.
In antiquity, the paddle boats (galleys and galleons), the bowline was a punishment by which the condemned was run throughout the ship, while beating him.
Location de bateaux et excursions en voilier à Palamos, Costa Brava, Espagne