Section 8 - Ship Construction and Dry Docking Flashcards

Question

What requirements are there for opening through water tight bulkheads?

Answer 1

1 minimum amount possible; 2 small as possible; 3 high as possible; 4 should not affect watertight integrity; 5 any doors, covers, etc. must maintain watertight integrity 6 must not fail due to fire or heat. 7 should not affect the strength of bulkhead - strengthened by thicker plating

Answer 2

- As small as possible; - As high as possible on the bulkhead; - Pipes must be flanged — not welded on to the bulkhead; - Opening in bulkhead strengthened, - Studs or bolts should not pass through bulkhead, - Valves fitted to tank bulkheads, should be fitted outside the tank, with operating handles on deck; - Valves on collision bulkhead should be aft of bulkhead, with operation from above deck; - Jointing should not fail due to pressure or heat.

Answer 3

- As high as possible on the bulkhead; - Pass through a watertight/fire retardant gland; - Should not fail due to pressure or heat.

Answer 4

- Be the same strength as bulkhead, - Be watertight; - Can be hand operated locally from either side; - Can be operated with a 15 degree list. - Operated from above bulkhead deck, such as a damage control centre; - Indicator at remote operational position. - When power operated should have audible alarm - Below the load waterline, doors must be of the sliding type. Above the load waterline, hinged doors are permitted

Answer 5

- Valves should be made of cast steel, bronze or of equivalent ductile material, NOT cast iron. - Valves are flanged at the ends - The hull opening should be strengthened, (usually by a flange). - Bolts and studs should not pass through the hull. - The fitting should maintain watertight integrity. - All valves should be fully accessible. - All valves should be fitted with an open / shut indicator. - All sea water inlets must have gratings on the outside of the hull. - Pipes should be heavy gauge steel, copper or of equivalent material.

Answer 6

- Increase ships speed - Reduce pitching - Increase buoyancy forward - Reduce the bow wave by wave cancelling

Answer 7

Advantages * May give 2-3%improvement in hull efficiency * May improve propeller efficiency by 8% * Reduction in bow wave making. * Increased capacity of the forepeak tank * Possible improvement in steering * Possible reduction in pitching. Disadvantages * Increase in skin friction due to larger surface area. * Vulnerable to damage in port or when manoeuvring. * May give rise to whipping after slamming in heavy weather. * Possible increased construction costs. * In collision will cause damage to both vessels beneath the waterline.

Answer 8

- Shafting - Propeller - Auxiliary Machinery - Main Propulsion Machinery - Wave induced vibration

Answer 9

- Structural stress, stress that affects the whole vessel; - Local stress, stress that only affects a particular part of a vessel.

Answer 10

- Dynamic stress, stress caused by movement of the vessel - Static stress, stress caused by local effects.

Answer 11

- Tensile stress, a force that tends to increase the length; - Compressive stress, a force that tends to decrease the length; - Shear stress, when two opposing forces cause the various parts of the section to slide on over the other.

Answer 12

- Heavy seas, when the waves and boat length are equal - Badly distributed cargo

Answer 13

It is caused by fluctuating water pressure squeezing the hull. It most severe forward of the collision bulkhead when the vessel is running into a head sea and pitching heavily.

Answer 14

Local stress that is caused by a vessel being driven into a head sea. The bottom of the hull, aft of the collision bulkhead starts to fill in, creating a flat area. It is most severe in light ship conditions.

Answer 15

The transverse distortion of the structure caused by rolling in a beam sea.

Answer 16

- Pitch - Heave - Yaw - Roll - Surge - Sway