MEO Orals on Naval Architecture Function 3 Part 1
MEO Orals on Naval Architecture Function 3 Part 1
What is bow thruster ?
- Bow thrusters are maneuvering devices which are fitted in an athwartship tunnel near to the bow and aft of the collision bulkhead.
- It gives additional maneuvering ability.
What is bulwark ?
- A barrier fitted at the deck edge to protect passenger and crew to avoid the loss of items overboard while the ship rolls excessively.
Why fitted double bottom or DB tanks on ships ?
- It is fitted to prevent foundering (flooding) in the event of hull damage.
- To control the stability by ballasting
- To provide buoyancy
- To store F.W and F.O
Why fitted wing tanks ?
- To control the ship stability (healing)
- To carry cargo
- To store F.W and F.O
What is half beams ?
- Transverse beams which are cut at hatch side coamings are termed half beams.
What is water tight bulkhead ?
- Water tight bulkheads are important element of transverse strength, particularly against racking stress.
- They divide the ship into subdivision.
- They also give protection against fire and founder
What is collision bulkhead ?
- Collision bulkhead is a forepeak watertight bulkhead to protect foundering and against racking stress.
- It is fitted not less than 5% or not more than 7% of the ship length aft and stern at load water line.
- It must extend to upper deck.
- Stiffners may be spaced 600 mm apart.
- Its water tightness can be tested by filling the fore peak tank to the level of water line or hose test along the boundary. No water leak through other sides.
What is after peak bulkhead ?
- One bulkhead at each end of the machinery space
- To enclose the stern tube in a watertight compartment.
- This bulkhead need only extend to first deck above load water line, if it forms a watertight flat.
- Plating in after peak bulkhead must be doubled or thickened around the stern tube to resist vibration.
How do you check water tight door’s tightness ?
- Watertight hatch cover and watertight doors’ tightness can be check by chalk method or hose methods.
What is chalk method ?
- Apply chalk to watertight flat sealing continuously.
- Close the door tightly, then open
- Check the watertight door sealing.
- The chalk must have continuously around the watertight sealing, it has water tightness.
What is hose method ?
- Close the watertight door or watertight hatch cover tightly.
- Hosing with water jet with a pressure of 2 bar and directed to the sealing edges away from 1.5 m.
- There must be no water leak through the other side.
- That door or hatch are good in order for watertight.
Dead weight and light weight ?
- Dead weight is the weight of cargo, fuel, water, store etc. that a ship can carry.
- Light weight is ready to sea going but no fuel, no crew, no cargo.
- Displacement = Dead weight +Light weight
What is windlass ?
- It is a machine used for hoisting or lowering anchor.
What is stern tube ?
- It is a watertight tube enclosing and supporting the propeller shaft.
- It consists of a cast iron or cast steel cylinder fitted with bearing surface up on which the propeller shaft (enclose in a sleeve) rotates.
What is hatch coaming ?
- The vertical plating bounding a hatch for the purpose of stiffening the edges of the opening and resisting entry of water to ship hull.
What is girders?
- The continuous stiffening member which run fore and aft in a ship to support the deck.
What are stealer strake, stringer, stringer plate ?
Stealer strake:
A single wide plate which replace two narrow plates in adjacent strake of a ship.
Stringer:
A horizontal stiffener fitted along the ships’ side or a longitudinal bulkhead, in order to provide strength and rigidity.
Stringer plate:
The outboard strake of plating on any deck.
Reference:
Oral Guide by – MIN ZAR TAR