KNOTS AND PROPS
Man has used the sea for transportation as well as a food source for centuries. Rowing a boat is labor intensive, so harness the wind. So enters sail power. The use of knot tying line for control and ship’s power was essential.
Sailing knots include the bowline, cleat hitch, figure eight, and others do the work. Old Bosun Mates knots or BMs date back to the 13th century. Some knots are decorative while others are necessary and practical. True sailors must learn how and which knot to use and when.
Knots for speed is a unit of speed equal to one NAUTICAL mile per hour. The nautical knot is approximately 1.15 STATUTE mile (i.e. land mile) per hour. The term originated in the 17th century when sailors used common log (a rope with knots tied in it) to measure a ship’s speed. Knots are used because knots are directly related to nautical miles based on the earth’s latitude and longitude. One nautical mile equals one minute of latitude. Fishing knots are used to attach lures, weights, and specific knots to prevent slippage are a must for the professional as well as the recreational angler.
Propellers commonly called props are categorized into fixed pitch or controlled pitched types. Fixed props have a permanent fixed blade angle while controlled pitch types can be changed.
Three, four, five, even six bladed props can be aluminum or stainless steel to offer you the best choices. There is even a weedless prop. Match your prop to your boat for the best performance. Consider this: the prop cuts through the water and pulls the water down and back toward the stern. This causes the boat to move forward. Runabout or aircraft carrier, they all work the same way.
propellers.
Airplane owners have propellers on their piston engine aircraft. The propeller has a pitch (angle) either fixed or variable (controlled). There are specialized props as well. As a boat prop moves water an aircraft moves air. It’s as if you reach out in front of you while swimming and pull water back towards you to move forward. The aircraft spinning prop pulls the air back towards the rear of the aircraft thus moving the plane forward.
Planes or boats, man strives to conquer the environment. Work or play, from dugout canoe to spacecraft, the brilliance of the human mind tries to find a better way. It drives us forward.
