Q41- Important Checks to rudder and Propeller in a DD?

Answer

RUDDER Checks

• WE SHOULD OBSERVE THAT NO WATER SHOULD BE COMING OUT OF THE RUDDER. ITS A VISUAL

INSPECTION TO CHCK THE INTEGRITY OF THE RUDDER AND NOT THE FINAL CHCK.

• RUDDERS TOP AND BOTTOM PLUGS ARE REMOVED TO FIND IS ANY WATER COMES OUT OF IT.

• HAMMER RUDDER PLATES AND CHCK SOUND AND CONDITION OF RUDDER PLATES.

• G AUGING OF PLATES SHOULD BE CARRIED OUT IN VESSELS MORE THAN 5 YEARS OLD.

• CHCK THE CONDITION OF ZINC BLOCKS.

• RUDDER IS MOVED AMID SHIP AND SEE ACTUAL POSITION OF RUDDER W.R.T SHIP. THIS WILL HELP TO

IDENTIFY TWISTING OF RUDDER STOCK.

• PINTLE CLEARANCE TO CHCK.

• JUMPING CLEARANCE TO BE CHCKED.

• WEARDOWN AND RUDDER DROP TO BE CHCKED.

• VISUAL INSPECTION FOR RUDDER CORRoSION, PITTING, CRACKS ETC.

• Coupling BETWEEN RUDDER AND RUDDER STOCK CEMENT TO BE CHCKED, CHIP OFF THE CEMENT AND

CHCK CONDITION OF PALM BOLTS.

• RUDDER PRESSURE TSTING HAS TO BE CARRIED OUT..

PROPELLER CHECKS

• General Condition: Inspect the overall condition of the Propeller. Look for visible damage such as cracks,

dents, and corrosion..

• Blades: Check each blade for signs of wear, cavitation, and erosion. Measure blade thickness if necessary.

• Hub: Examine the hub for cracks and any signs of water ingress.

	Propeller is divided into 3 parts	A,B,C
	MAXIMUM STRESS A>B>C
	THICKNESS A>B>C

Oral study illustration

3. Measurement Checks

 Measurement of wear down

 Propeller nut and Propeller shaft threaded end;

 Cone, key and key way (keyed shafts), including examination by an efficient crack detection method of the after end of the cylindrical part of the shaft and one-third of the length of the ta aper from the big end;

 Where Propeller is fitted by a solid flanged coupling at the after end of the shaft t, non-destructive examination of the flange fillet area of the shaft;

 Propeller shaft bearing areas;

 Stern bushes/bearings;

 Shaft sealing arrangements, including lubricating oil system.

 Blade Pitch: Measure the pitch of each blade to ensure they are consistent and within design

specifications.

 Diameter: Measure the diameter of the Propeller to check for uniformity and ens sure it matches the original specifications.