Log Book -Week 5

Work Week: 5 (9-13 July 2018)

9 July (Monday)

·         Continue prove all the rule value based on the calculation on the rudder chapter 10.

·         Ask collages with the part not understand.

10 July

(Tuesday)

• Discussing with Mr Amin about the results I calculated in excel.
• Being taught by Mr Amin the part that I didn’t get, included

-          The orientation of rudder maximum is 35֯ at one side. (stopper will apply)

-          Tiller is a part connected between steering gear and rudder.

-          Jumping collar is a part to ensure the rudder from being lifting.

-          Dye penetration, magnetic particle test and ultrasonic test.

-          When rudder stock does not exceed 350mm, the coupling flange may be weld into the stock, provided that its thickness is increased by 10%.

-          Then the assembly is subjected to heat treatment. (stress relief)

-          The coupling flange welded, the grade of the steel used is to be weldable quality. (carbon content not exceeding 0.23%)

-          Rudder trunks which are open to the sea, a seal or stuffing box is to be fitted above the deepest load waterline, to prevent water from entering the steering gear compartment and the lubricant from being washed away from the rudder carrier.

-          Tiller key is the part making sure the rudder from being move.

-          Testing included structural testing, hydropneumatic testing, leak testing and hose testing.

-          If rudder is constructed with double plating, the inspection required is leak testing.

·          Ask by him to continue read nozzle part.

11 July

(Wednesday)

• Propeller nozzle details drawing is given by En Amin.

• The nozzle is being classed by details below:

The requirements of this Article apply to scantling steering nozzles for which the power transmitted to the propeller is less than the value obtained, in kW, from the following formula

P=16900/dm

where: dm is the Inner diameter of the nozzle, in m.

Thus, P=16900/1.730= 9768.786kW.

From the drawing, the power of generator is 50kW which is less than 9214.83kW. The scantling steering nozzles can be applied.

Nozzles normally consist of a double skin cylindrical structure stiffened by ring webs and other longitudinal webs placed perpendicular to the nozzle. One of the ring webs is to be fitted in way of the axis of rotation of the nozzle.

The thickness of the inner plating of the nozzle is to be not less than the value obtained, in mm, from the following formulae:

The thickness of the inner plating should be at least 22.7mm by using the formula above. The thickness of the outer plating of the nozzle is to be not less than (tF − 9) mm, which is 22.7-9=13.7mm. The thicknesses of ring webs and longitudinal webs are to be not less than (tF − 7) mm, which is 22.7-7=15.7mm.

Care is to be taken in the manufacture of the nozzle to ensure the welded connection between plating and webs. The internal part of the nozzle is to be adequately protected against corrosion. Upon completion of manufacture, the nozzle is to be subjected to a leak test. An efficient indicating liquid, such as soapy water solution, is to be applied to the weld. Prior the inspection, it is recommended that the air pressure in the tank should be raised to 0.2 bar and kept at this level for approximately 1 hour to reach a stabilized stage. The welding part is accepted if there is no bubbles come out.

12 July

(Thursday)

• The result is discussed with En Amin.

• The "Y" Bracket Detail Drawing is given by En Amin.

• Study the book (Pt B, Chap 10, Sec 3) to analysis the drawing.

13 July

(Friday)

• There are 2 type of propeller shaft bracket: single arm and double arm.
• Y bracket shaft is a double arm propeller shaft bracket.
• It is to be checked that the bending stress ,the compression stress and the shear stress are in compliance with the following formula:
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• The calculation is done in excel file
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