A Case of the Shakes

Being out on the water presents a wonderful opportunity to de-stress, but too much vibration can shake your hardware loose and detract from your enjoyment.

We were reminded of this fact during a recent pre-purchase survey, when the surveyor noted excessive vibration and recommended a repair. After the purchase, the buyers took the boat to a repair yard, where the shaft was replaced. Unfortunately, the problem persisted, and they visited another repair facility that suspected the prop and removed it for reconditioning.

As you might have guessed, after the work at both yards, the problem remained. The owners’ story is a lesson in how challenging it can be to diagnose vibration problems correctly.

FIRST THINGS FIRST

Before going down the rabbit hole of vibration mysteries, start by having a mechanic come on board for a test run. Boat owners can become desensitized to sound and vibration, and a technician with trained eyes and ears can uncover problems that an owner may not recognize.

In this case, on the trial run, there was no question something was up. Starting around 2500 rpm, a thrumming sound radiated from the drivetrain. This disturbance only increased the faster the boat went.

Before diving into more serious troubleshooting in this type of situation, a diver may need to be called or the boat may need to be hauled to verify the propeller condition. In