42 BASIC POWERBOATING. SAFETY & RESCUE FOR SAILING INSTRUCTORS


Effect of Wind Shifts on Coming Alongside Generally, anchored boats point into the wind, unless the current is stronger. Before making your approach, determine the amount and quickness of the anchored boat’s oscillations and adjust your approach angle accordingly.


Large-Angle Approach: this approach easily compensates for oscillations in moored boat’s swinging motion.


Small-Angle Approach: if boat swings any farther, you will have to stop and hold position until it swings back.


Straight Approach: will have to stop and hold position until boat swings back.


HIGH-SPEED MANEUVERING Chine Thrust


As a boat rolls in a tight turn, it also slides sideways. If the boat has a chine and hits a wave sideways at high speed, it could trip over its chine or throw someone overboard.


When running at high speed, a boat is less affected by wind. Other considerations become important, such as sea conditions, wake from other boats, and semi-submerged objects in the water. Hard impact at high speed can cause loss of steering control, damage to powertrain or hull, and possible injury to occupants. Any gear that is not carefully stowed or secured can take flight when maneuvering at high speeds, especially through waves. Constant alertness, a safe attitude, and quick responses by the driver are at a premium. To be able to respond promptly, keep a hand on the throttle at all times.


During turning maneuvers, thrust from the propeller causes the boat to roll on its longitudinal axis. As the speed and tightness of a turn increases, the amount of roll increases. In a sharp turn with the boat rolled at a substantial angle, propellers on outboards and stern drives are closer to the water surface, which can result in air being drawn into its blades (sometimes referred to as ventilation). When this occurs, there will be a sudden increase in engine rpm and loss of propeller power. To avoid possible damage to the engine and drive system, the rate of turn and/or speed should be reduced immediately. If the drive unit is trimmed up too much, it can aggravate this problem.


High-Speed Safety Tips E All occupants should be in seats and/or have a secure grip on boat. E Steady your throttle hand along the base, and the other on the wheel. E Maintain an alert lookout; don’t get distracted. E Use moderate and measured steering adjustments. E Warn occupants prior to sudden changes in speed and direction. E Avoid abrupt stops. E If in doubt, slow down.


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