Vibration coming from prop shaft strut

I was up under my boat this weekend checking my prop and decided to give it a spin. While the prop spun freely there was a very loud vibration coming from the strut just ahead of the prop. I'm assuming there is a set of bearings inside this metal strut. What could be causing the vibration and what does it take to service?

It takes water! I assume you do not feel this vibration when driving it? The strut will typically be sticky when on dry land.

Water... It is a nylon bushing and it uses water as a lubricant. Try hosing it down and spinning it. The vibration you hear/feel should go away.

Thanks. I'll give it a try