NAUI Master Scuba Diver 270 Boating, Diving, and Seamanship er diver down flag on the trail line is also very useful. • Prepare your divers’ down-line at mid-ship, if used. The anchor line can also be used for descending and ascending by divers. • Many boats deploy a precautionary decompression line with extra scuba cylinders and regulators at a depth of 5 m (15 ft) to encourage divers to make a recommended safety stop. KNOTS Perhaps the most mystifying of all the nautical skills is the tying of knots. Of the over 2,000 kinds of known knots, you can comfortably and safely get by with nine basic knots (figure 12-11). Knowing which knot to tie for the proper application is an important and admired nautical skill. Your knot tying abilities are useful above as well as below the water. The following explanations of these knots describe the knot, as well as the use of each one. Only practice will make you proficient at making knots. Since many knots are used under water as well as above, it is a good idea for you and your buddy to practice tying knots under water wearing your diving gloves. Figure Eight Knot Used to prevent a line from unlaying or running through a block. Will not jam. Bowline Makes a temporary eye in a line. Might be used as a temporary substitute for an eye splice in mooring line. One of the strongest, practical, and most useful knots. Square Knot (Reef Knot) Quick way to join two ends. Is secure only if the two lines are the same size and the knot is pressing against something, such as the rolled part of a reefed sail. May “capsize” and come apart under strain if not supported. Becket Bend (Sheet Bend) Used to join two ends when knot must stand alone in “mid-air.” Will work with lines of different sizes. Round Turn and Two Half Hitches Quick way to make fast to anything of any shape. Remains secure with or without strain from any direction. Can jam and be difficult to untie. Clove Hitch Quick to make and will not jam. Secure when made around cylindrical object and strain remains steady but can loosen if standing part goes slack or strain comes from varying directions. Rolling Hitch Quick, secure, and adjustable. Knot can be slid along spar or line without loosening. Bowline On A Bight Handy if you need an eye but the ends are not available. Sheepshank (Theoretically) used to take up excess slack or strengthen a weak spot in a line. Will hold if very carefully made and strain is absolutely steady. When a line is cut, it tends to unravel. “Whipping” is twine that is wrapped around the end of a line to keep it from unraveling.
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