Propeller, Shaft and Rudder Work During a Bali Haul Out

Written and maintained by the Bali Shipyard Build Desk · last reviewed 19 August 2026

In Bali’s warm water, running gear works harder than most owners assume. Fouling loads the propeller, growth in the shaft log accelerates bearing wear, and electrolysis is more aggressive than in cooler water. Annually, with the boat out, is the moment to get honest numbers.

Cutless bearings

The cutless bearing supports the shaft in the P-bracket or stern tube. It wears, and when it does the shaft moves — which then destroys the seal, unbalances the propeller and vibrates the whole drivetrain.

Check: grip the shaft near the bearing and try to move it vertically and laterally. Any perceptible play at that point is more than it appears at the propeller. Also look for uneven wear patterns, which indicate misalignment rather than simple age.

Note: a cutless bearing that has worn unevenly is a symptom. Replacing it without addressing the alignment behind it means replacing it again next year — see the alignment discussion in repowering in Bali.

Shaft seals

Seal type	Check	Common failure
Traditional stuffing box	Packing condition; gland adjustment; hose and clamps.	Over-tightening scoring the shaft; perished hose.
Dripless face seal	Bellows condition and age; carbon face wear; vent line clear.	Age-expired bellows — a genuine sinking risk.
Lip seal	Lip condition; shaft surface at the seal.	Grooved shaft at the running surface.

Shafts

• Straightness. Checked on rollers or in place with a dial indicator. A bent shaft causes vibration that gets blamed on the propeller and destroys bearings and seals.
• Surface condition at the bearing and seal running surfaces. Grooving means the seal will not seal regardless of how new the seal is.
• Corrosion and pitting, particularly near the coupling and where the shaft sits in the log.
• Keyway condition and coupling fit.
• Withdrawal. Periodically the shaft should come out entirely for inspection along its full length. It is the only way to see what is hidden inside the log.

Propellers

Propellers get treated as durable, and they are not. Small damage has a disproportionate effect on efficiency and vibration.

• Edge damage and dings — even minor deformation of the leading or trailing edge costs efficiency and generates cavitation.
• Erosion and cavitation burn on blade faces, usually a symptom of a pitch, alignment or flow problem rather than a propeller problem.
• Balance and pitch accuracy. A propeller can be checked and reconditioned to specification; on a boat that vibrates, this is often the answer.
• Pitch against performance. If the engine cannot reach its rated wide-open-throttle rpm, the boat is over-propped and the engine is being overworked continuously. Re-pitching fixes it.
• Rope cutters, which in Indonesian waters with widespread fishing gear and floating lines earn their cost quickly.

Rudders

Rudders are inspected less than they should be and fail expensively.

• Bearing clearance — measured at the blade, where a small clearance at the bearing shows up as significant movement.
• Stock condition where it enters the blade. Corrosion here is hidden and is the classic cause of a rudder failing at sea.
• Water inside the blade. A hollow rudder that has taken water is heavier, can freeze internally in cold climates and, more relevantly here, corrodes the internal structure. Drill-and-drain testing at haul-out answers it.
• Steering linkage, quadrant, tiller arm and stops, including the emergency steering provision, which nobody tests until they need it.

Anodes and bonding

Running gear is where galvanic protection is proved or disproved. Anodes are measured, not glanced at, and the rate of consumption is as informative as the amount remaining. An anode that disappears in months indicates a fault — commonly a bonding problem or stray current — rather than a need for a bigger anode. This is covered fully in tropical corrosion control.

Record the measurements

Every one of these checks produces a number: bearing clearance, shaft runout, blade thickness, anode consumption. Recorded consistently, they turn into a trend, and a trend tells you when something is going to fail before it does. Recorded nowhere, each haul-out starts from zero and everything looks acceptable.

How to keep that record usable is covered in documenting repairs for insurance and survey, and the scheduling that makes it happen is on yacht maintenance Bali. To plan the lift where the work happens, see Bali haul out and dry dock.

Diagnosing vibration before you replace anything

Vibration is the symptom most often treated by replacing the propeller, and the propeller is often innocent. Work through the causes in order rather than in order of cost:

Symptom	Likely cause	Check
Vibration at all speeds, worse with load	Shaft misalignment	Alignment measured afloat after settling.
Vibration appearing at one rev band	Propeller balance or blade damage	Blade inspection; balance and pitch check.
Rumble with play at the shaft	Cutless bearing wear	Physical play test at the bearing.
Vibration after a grounding or line strike	Bent shaft or distorted blade	Shaft runout on rollers; blade geometry.
Steering-related vibration	Rudder bearing clearance	Play measured at the blade, not at the stock.
New vibration after a repower	Alignment set on blocks, never re-checked	Re-align afloat and after running-in hours.

Building a running-gear baseline

The first haul-out where all of this is measured is the expensive one, because everything is unknown and everything looks acceptable. From the second onwards, you are comparing against a baseline, and comparison is what turns an inspection into a prediction. Record clearances, runout, blade condition and anode consumption in the same format each year, and the boat starts telling you when a component is entering its last season rather than surprising you in the middle of one.