Material of the propeller and possible damage during operation

For outboard motors manufacturers usually use the aluminum propellers  and stainless steel propellers.. Aluminum propellers cheaper , than stainless steel propellers. The stainless steel prop allows to obtain a small increase in speed compared with aluminum propellers because of the possibility to make a thinner blade. Advances in technology, design improvement and production of aluminum propeller  given such excellent results that their characteristics are in no way inferior to their counterparts made of stainless steel. That is why on most small boats such set of aluminum screws. Major damage to screw arise from contact with the bottom of their reaching the shore or striking a submerged obstacle in the form of drift wood, stumps, remnants of buildings under water artificial  reservoirs, etc .. Light damage in the form of notches on the edges of the blades are removed easily with a file . Bent blades can be corrected using the mallet. However, it happens that the collision of fragments detached blades. In this case, the repair is possible with the use of welding equipment. The price of repair of aluminum or stainless steel propeller is approximately the same. Use of  ”repaired” propeller is possible, but often fail to fully recover their original driving parameters. It should be noted that the badly damaged propeller are bent and propeller shafts.. Propellers  shafts as eligible for special equipment. However, the more powerful the motor, respectively, the thickness of the shaft, edit them harder and harder. Another common injury is a screw rotation of the sleeve, id est separation of the rubber damper on the sleeve. In appearance it is almost invisible. Rotate the sleeve behaves under load, speed outboard soaring, and the speed is not increased. This type of damage is not repaired propeller