Test

Question 1

What is hogging and sagging

Answer 1

Hogging: ship is supported midships by the wave crest, while ends are unsupported
Sagging: hull is being supported at each end by the crests of adjacent waves while midships is unsupported

Question 2

What is the ships structure and categories

Answer 2

Divided into 3 categories:

Primary: contributes to the Main structural strength of the ship (principal decks, watertight bulkheads)

Secondary: does not primarily contribute to structural strength but contributes to watertight integrity and support local loads

Minor: contributes to neither structural nor watertight Integrity

Question 3

Factors necessary for brittle fracture

Answer 3

Low temperature, presence of a stress raiser, low toughness steel.

Question 4

How to prevent brittle failure

Answer 4

Modern steels now manufactured with guaranteed notch toughness

Question 5

What is fatigue failure caused by?

Answer 5

Caused by repeated cyclic stresses such as hogging, sagging, racking, and slamming combined with presence of a weak point such as a sharp corner, discontinuity of strength or weld defect

Question 6

What is the resultant loss of strength caused by cutting holes in structure compensated by?

Answer 6

• rounding corners
• fitting a rider plate
• fitting an insert plate
• adding additional stiffening

Question 7

Where can serious corrosion inside ship occur; examples?

Answer 7

Can occur where areas are:
- difficult to maintain
- subject to heat and moisture
- frequently submerged in bilge water

Examples:
- fuel tanks
- ballast tanks
- sewage tanks
- passageways

Question 8

Techniques to keep corrosion to a minimum?

Answer 8

• use fresh water when washing paintwork. Mandatory when preparing surface prior to painting
• in bad weather protect paintwork by using screens
• dehumidification will reduce moisture in air
• air conditioning will reduce amount of airborne contamination and humidity in ship

Question 9

What is the periodicity for surveying guardrails

Answer 9

• all guardrails, guardwires surveyed every 6 months according to the maintenance schedule
• before and after rigging
• prior to locking down dockyard should survey them

Question 10

What is the procedure for surveying guardrails

Answer 10

Routine examination of all stanchions, stays, wires, fittings, and nets

Question 11

Typical defects with guardrails?

Answer 11

• distorted or seized components
• cracked welds
• defective fittings
• missing parts
• galvanized items corroding

Question 12

Requirements for mess deck Improvements

Answer 12

• tropical hardwoods used in construction and repair of ships must be from sustainable sources
• use of mahogany restricted
• orders must be accompanied by letter explaining reason for order
• wood not to be purchased abroad to prevent parasites

Question 13

Examples of defects in salt water systems

Answer 13

• pipework damaged after being used as a strong point for lifting equipment
• defective brazed joints
• defective valves due to erosion or corrosion
• leaks from joints
• holes caused by impingement

Question 14

Two categories of corrective maintenence for SW system?

Answer 14

Temporary:
- repairs done on board by ships staff
- enable system to be used, but will require further work when resources become available

Permanent:
- repairs done onboard or ashore which require no further work

Question 15

What are some materials for temporary repair?

Answer 15

• glass fibre tape and epoxy resin for holes in pipes or defective brazing
• epoxy resin or chemical metal for pitting of flanges and valve seats
• soldering or brazing
• DC pipe clamps for pipe fractures

Question 16

What are some materials for permanent repair?

Answer 16

• holes in pipeword or flanges resolved only by renewing length of pipework or flange
• defective valves refurbished or renewed
• flange and compression joints broken, repaired, and remade

Question 17

% of air in type 23 vented?

Answer 17

10% fresh air, 90% recirculated

Question 18

What does AC seek to control?

Answer 18

• temperature
• humidity
• purity
• flow
• boundary

Question 19

What are the purposes of vent maintenance?

Answer 19

• maintain efficiency
• preserve materiel
• prevent failure/ breakdown
• reduce defects

Question 20

What is a citadel?

Answer 20

Compartments grouped together with gastight boundary in which recirculating of air and normal passage for personnel is possible without contamination

Question 21

When are citadel tests done?

Answer 21

• annually
• prior to DED to locate leaks and ensure those beyond capacity of ships staff are included in defect list
• during harbour acceptance trials
• during sea acceptance trials
• during FOST work up

Question 22

Effects of raw sewage dumped into sea?

Answer 22

• B.O.D of organisms in faecal matter will cause deoxygenation of water
• suspended solids level in water will increase
• disease producing organisms entering food chain via shell fish
• is an asthetic nuisance and health hazard

Question 23

When is discharge of sewage permitted?

Answer 23

• within 3 NM of coast , provided an IMO approved sewage treatment plan in operation
• between 3-12 NM of coast if IMO system comminute and disinfects sewage
• over 12 NM from coast, no treatment necessary

Question 24

What are some safety measures?

Answer 24

• smoking, eating, drinking, hand to mouth contact prohibited
• personnel in date for polio, tetanus, TAB vaccines
• proper PPE: rubber gloves, face mask, goggles etc
• personnel with cuts and abrasions not employed unless wound protected
• if personnel becomes ill medical officer informed about job in sewage plant
• to reduce spread of contamination, any equipment removed from soil or sewage treatment cleaned, carried in suitable container