15. Describe structure of single acting arrangement, principle of installation, designing of the shaft? ( Given figure)

1.  Arrangement of the single shafting

1- E/R bulkhead

2- Stern tube

3- Water tank

4- Propeller shaft

5- Intermediate shaft

 6- Intermediate bearing

7- Thrust shaft

8- Thrust bearing

9- Double bottom tank

2.  Installation principle of the shafting.

-There is one or more shaft line depending on kind of ships

-In almost cargo ships,  only one propeller and one shaft line

-A shaft line is placed parallel with the keel of the ship; in some case the shaft line is placed unparallel with the keel. It makes with basic line an angle a, a £ 5o

-In MPP with two shaft lines, they make with the vertical keel section angles b, b £ 3o (in some special cases a is permitted till 15o)

-The shafting should be shortened.

Hinh αβ

3.  Position of shaft bearings.

Shaft bearings are usually positioned near bulkhead or keel of the ship where ship's hull structure is strongest.

Position of the shaft bearings relates to vibration of the shafting.

According to the rule of Russia Register:

If D ≥ 100 mm, then

12D < L < 22D

Where: D - Diameter of a shaft

    L - Distance between shaft bearings.

If D < 100 mm, L is calculated:

Lmax =91.3√D^2