How to Align the Shaft on a Ski Boat

How to Align the Shaft on a Ski Boat
Small boats, including ski boats, utilize a propeller found at the end of a shaft coming off the end of the boat to move the boat forward. Although smaller crafts can withstand a slight deviation in the alignment of the propeller shaft, a propeller shaft that is misaligned by a quarter of an inch or more can result in major operational and steering problems. Fixing the alignment of your ski boat's propeller shaft involves checking the original shaft for imperfections and replacing if necessary.

Instructions

Difficulty: Moderate

Things You’ll Need:
  • Swimwear Ski boat trailer Ski boat owner's manual Socket wrench Screwdriver Rubber mallet V-blocks (at least 2) Dial indicator
  • Swimwear
  • Ski boat trailer
  • Ski boat owner's manual
  • Socket wrench
  • Screwdriver
  • Rubber mallet
  • V-blocks (at least 2)
  • Dial indicator
Step 1
Check the security of the propeller shaft's fit into the shaft coupling while the boat is in the water. Wear the proper swimwear. With your hands, feel the connection between the propeller shaft and the coupling. Make sure that the space between the shaft and coupling is uniform around the shaft's perimeter.
Step 2
Make sure that the propeller is stable within the coupling. Work the propeller shaft back and forth to see if there is any give in the coupling connection. The shaft should have very little play back and forth. Replace the coupling if there is too much give. Reference your ski boat owner's manual for propeller shaft coupling removal instructions. You will need common hand tools, such as a socket wrench and screwdriver.
Step 3
Take your ski boat out of the water and transport it to your workspace on a ski boat trailer.
Step 4
Remove the propeller. Find the propeller nut and use a socket wrench to loosen and remove. Use a rubber mallet to tap the propeller cap forward to loosen. Reference your ski boat owner's manual for proper propeller removal instructions.
Step 5
Remove the propeller shaft from your ski boat. After removing the propeller, you generally need to remove an additional cotter pin to free the shaft from its coupling.
Step 6
Check the propeller shaft for cracks and other imperfections. If you can see any, have a certified ski boat technician check the shaft to see if it must be replaced.
Step 7
Lay the propeller shaft out on a pair of V-blocks so that it is parallel to the ground. Use a dial indicator to check the straightness of the shaft by holding the dial indicator directly above the shaft as your rotate the shaft beneath it. Check three or four different places across the entire shaft. If the dial indicator shows a deviation of 0.1 mm during this test, replace the propeller shaft. Contact your ski boat's manufacturer to find where you can purchase a new propeller shaft.
Step 8
Install your new propeller shaft into the coupling using the cotter pin provided in the packaging. Secure the propeller over the shaft by tapping it into place with the rubber mallet and securing the propeller nut.

Tips & Warnings

 
Do not let anyone operate the boat while you are attempting to check the propeller. Operating the ski boat during alignment may cause injury or death.
 
Do not let anyone operate the boat while you are attempting to check the propeller. Operating the ski boat during alignment may cause injury or death.

Article Written By Steve Brachmann

Steve Brachmann has been working professionally as a freelance writer since 2007. Hailing from Angola, N.Y., his work has been published in "The Buffalo News," SUNY-Fredonia's "The Leader" and on various websites. He is currently attending the State University of New York-Fredonia to earn a Bachelor of Fine Arts degree in acting with a communication minor.

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