Once a boat’s hauled out of the water, it’s a lot easier to inspect the propellers, prop shafts, seals and zincs. It’s also a good time to get any needed repairs or maintenance done, rather than waiting until the start of next season when everyone else is clamoring to get their boats fixed. Let’s check out the major inspection points.
Whether you own an inboard, sterndrive or outboard, carefully scrutinize the propeller blades for damage. Dings and missing chunks are easy to spot, but a slightly bent blade may not be readily apparent, though you can often feel it when underway because it usually creates vibration. Looking at a prop from the side makes it easier to spot a bent blade.
Another way to determine if a blade is bent is to measure the distance between the outermost edge of each blade and a straightedge suspended from a fixed point such as the anti-ventilation plate of an outboard or sterndrive or the bottom of the hull of an inboard. If the distance substantially deviates for one or more blades, you have an issue such as a bent blade.
You can often fix small dings and chinks in prop blades by filing them down, but be careful not to remove too much material, because this can throw a prop out of balance. Major damage such as broken or bent blades requires the expertise and equipment of a prop shop for repair and rebalancing. While many shops can perform near miracles in fixing mangled props, sometimes a wheel is beyond repair and you’ll need to buy another one.
Vibration while underway can also be an indicator of a bent prop shaft. Any variation in the distance between blade tips and a fixed point, or a visible wobble, can also mean a bent shaft. For inboards, check out the bearings: The prop should be centered within them. Ultimately, if you suspect a shaft is not true, have a shop check and replace or retrue it as necessary. The shop should also check related components such as bearings, seals and couplers, which can be damaged by running a boat with a bent prop shaft.