Boatyard Tip: Inspect your propeller and shafts.

Don’t forget to inspect your propeller and shafts.

Regularly inspect any areas on the shafts that are immersed in water but have little or no water flow, such as within the stuffing box,under the propeller and prop nuts, and within the shaft log and cutless bearing. These places are particularly prone to crevice corrosion, which could weaken the shaft. Crevice corrosion is promoted by water that lacks oxygen. It helps to run the boat to clear areas of stale water. For example, cutless bearings are normally lubricated by water passing through grooves in the surface. Also, let the stuffing boxes drip a little, even when the boat is idle.

Periodically have your propeller shafts pulled and inspected by professionals. Most propeller shafts flex to some extent while running. The extent of flex depends upon such variables as shaft length and diameter, number and location of supports, size and trueness of the prop, and engine alignment. The less flex the better.

To perform a simple check of your cutless bearing, grab the shaft in the vicinity of the bearing and try to move it back and forth. If there is play, the bearing isworn and should be replaced. If your cutless bearing wears quickly, this can be a sign of problems causing undue flex.

Source: https://www.powerandmotoryacht.com/maintenance/boatyard-tip-inspect-your-propeller-and-shafts

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Source: https://www.powerandmotoryacht.com/maintenance/boatyard-tip-inspect-your-propeller-and-shafts