16 BASIC POWERBOATING. SAFETY & RESCUE FOR SAILING INSTRUCTORS Twist-Grip Throttle and Gearshift


For outboards with a separate gearshift lever on the side of the motor, the twist grip throttle will usually have a shift position marked on it to which the throttle should be set before shifting the lever into forward, neutral, or reverse, so as to prevent serious damage to the outboard.


Shear Pins and Safety Sleeves


All outboards have a designed weak link between the propeller and the propeller shaft to protect the engine and drive train if the propeller hits an object. Most outboards use a neoprene sleeve (neoprene hub) that is bonded to the propeller hub. When impact occurs, the bonding is broken, which protects the outboard. Although the bond has failed, there is usually enough friction in the neoprene hub to allow the engine to turn the propeller very slowly, often enough to return to safety. The propeller must then be removed and repaired. Smaller outboards may use a soft metal pin called a shear pin, which will break upon impact. Once the pin is sheared the propeller will no longer turn and it must be removed to replace the shear pin.


Outboard Inspection E Outboard controls operate smoothly. E Propeller blades, neoprene sleeve, or shear pin are intact. E Cooling water intake is clear. E Oil level (applies to four-stroke or two-stroke with separate oil tank); add oil if indicated.


E Fuel tank level; add if indicated. E Condition of fuel line (no cracks or sponginess) and connections.


E Any leaks in fuel system or gasoline odor in bilges. E Condition of battery cables (no cracks, abrasion or frayed wire) and battery (no corrosion at terminals and proper fluid level).


E Cables securely fastened to battery. E Condition of lanyard with one end securely connected to the lanyard stop switch.


E Attachment of safety chain, wire or line to boat and motor (applies to outboards fastened to the transom with screw clamps).


Photo Courtesy of U.S. Coast Guard


A safety lanyard attaches the driver to the ignition cutoff (“kill”) switch. If the driver falls overboard or is thrown from the steering station, the engine will immediately shut off. Wireless cutoff devices are also available.


Table of Contents


A shear pin breaks upon impact with the propeller, protecting the engine and the drive train from damage.


Most modern outboards use a neoprene sleeve bonded to the propeller hub that breaks upon impact with the propeller.


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