Stability, Watertight Integrity, Load-lines, heavy weather

Question 1

Important structural aspects of watertight integrity?

Answer 1

• Watertight doors
• Bulkheads
• Collision Bulkhead (first fwd transverse bulkhead)
• hatches and tanks
• Tank tops (plating attached to ship bottom framework) forms the top layer of the double bottom

Question 2

When should watertight doors be kept closed?

Answer 2

• Res Vis
• When underway
• Pilotage, coastal waters
• Heavy weather
• Any time Master deems dangerous

Question 3

What are the 3 classes and what do they mean?

Answer 3

• A, door that may be kept open during navigation but must be ready for immediate closure
• B, door that should be closed but can be opened if the crew are working in the adjacent compartment (no two adjacent cat B doors should be kept open
• C, Opening permitted only for passage through it

Question 4

Operating methods of watertight doors

Answer 4

• Remotely from the Bridge, if in remote control door will close automatically if it has been opened locally
• Locally from either side (including manually)
• Three movements in an emergency (close, open, close)

Question 5

What sort of planned maintenance is there for watertight doors?

Answer 5

• Weekly open and close from Bridge (<1min)
• 3 months, local manual test (<90secs)
• 3 months, 3 movement test

Question 6

What indications are there when a watertight door is in operation?

Answer 6

• audible and visual

Question 7

What is the purpose of load lines?

Answer 7

• Load lines is an international convention it was introduced in 1966 for the protection of the ship and the crew. They mark a maximum legal limit that a ship can be loaded up too.
• Due to different water densities the world is divided into geographical load line zones each with their own prescribed load line
• Information can be found in Ocean Passages of the world, routeing Charts, Load Line Charts

Question 8

What types of load lines are there?

Answer 8

For all vessels:

• Tropical Fresh
• Fresh
• Tropical
• Summer (all other load lines are based off this one)
• Winter
• Winter North Atlantic
• Timber vessels have an additional set of markings

Question 9

What is the deck line?

What is freeboard?

Answer 9

• A horizontal line that passes through the upper surface of the freeboard
• Distance from the waterline to the lowest point that water can enter the vessel

Question 10

How long does a load line cert last and what does it contain?
What is DWA and FWA?

Answer 10

• 5 years
• Assigned freeboard (distance between the Plimsol mark and freeboard mark)
• freshwater allowance

DWA
- The the number of mm the draft of a ship is allowed to change when going from saltwater to dock water and vice versa

DWA = FWA x (1.025 - Dock Water Density/ 25)

FWA
- The the number of mm the draft of a ship is allowed to change when going from saltwater to fresh water and vice versa

FWA = summer displacement / (TPC of SW x 4)

Question 11

What are the main consequences of heavy weather?

Answer 11

• Damage to cargo
• Damage to hull
• Loss of stability

Question 12

What is classed as heavy weather?

Answer 12

• Dictated in SMS

- Dictated in SMS

Question 13

Potential Hazards due to heavy weather?

Answer 13

• Leaks e.g. hatch covers
• Lost or loose cargo
• Parametric Rolling (head-on sea)
• Synchronised rolling (the sea is perpendicular to ships head)
• excessive speed

Question 14

Considerations when preparing for heavy weather?

Answer 14

• Heavy weather checklist SMS
• Cargo securing, there will be heavy weather securing plan in the Cargo Securing manual
• Check watertight seals
• Weather routing in passage planning

Question 15

Considerations when encountering heavy weather?

Answer 15

• Inform Master
• Safety of the ship (Navigation and securing)
• Safety of the crew (announcements, safety lines)
• Monitor ( weather and SOLAS danger report)