Q. Describe camber, sheer, tumble home, Rise of floor.
Ans.
Camber:-The transverse curvature of the deck from the centerline down to the sides. This camber is used on exposed deck to drive water to the sides of the ship.
Sheer: The curvature of the deck in a fore & aft directions, rising from mid-ship to the maximum at the ends. It makes a ship more seaworthy by raising the deck at the fore & after ends further from the water and by reducing the volume of water coming on the deck.
Tumble Home: In some ships, the mid-ship side shell in the region of the upper deck is curved slightly towards the center line, thus reducing the width of the upper deck & decks above.
Rise of Floor: The bottom shell of ship is sometimes sloped up from the keel to the bilge to facilitate drainage. The rise of floor is very small.
Q. What is freeboard and reserve buoyancy?
Freeboard: It is the distance from the waterline to the top of the deck plating at the side of the deck amidships.
Reserve Buoyancy: It is the potential buoyancy of a ship and depends upon the intact, watertight volume above the waterline.
When a mass is added to the ship, or buoyancy is lost due to bilging, the reserve buoyancy is converted into buoyancy by increasing the draught. If the loss in buoyancy exceeds the reserve buoyancy the vessel will sink.
Q. Why do tankers have less freeboard?
Ans. The value of GM is greater compared to other types of ships, the openings in the tankers are small than of other ship & also the permeability is more.
Q. what do u mean by the stability of ship? How does stable Ship returns to the upright position if heeled by an external force?
Ans. STABILITY OF SHIP: The tendency of the ship to come back to its upright position when healed by external force is defined as the stability of the ship.
When a ship is healed, the centre of buoyancy shifts, this forms a righting lever, thus acting in the opposite direction to upright the ship.
Q.What are tender and stiff ships?
Ans. Tender Ship: The ship with a small Metacentric height has a small righting lever at any angle & will roll easily is said to be a tender ship. In a tender ship, th
The GM is more than GZ. & these kind of ship are more stable.
Stiff Ship: The ship with a large Metacentric height has a large righting lever at any angle & has considerable resistance to rolling. A stiff ship is very uncomfortable. In a stiff ship, the Centre o
Ans. Free Surface Effect: When a tank of liquid is partially filled & the mass of liquid is moved. This movement affects the Metacentric height. This is called free surface effect.If free surface effects become more, then ship may capsize.
Ans. Purpose:-
o Avoid flooding of the ship in case of damage to bows.
Location
o The location is such that it is not so much forward as to get damaged on
o Minimum at 1/20 of ships length from forward perpendicular
o The collision bulkhead is continuous to uppermost continuous deck
o Collision bulkhead is 5 to 8 percent of ships length from forward.
Q. What are the types of bulkheads?
Ans.
a. Flat Bulkhead
b. Corrugated Bulkhead
c. Longitudinal Bulkhead
d. Transverse Bulkhead.
e. Watertight Bulkhead
f. Non-Watertight Bulkheadg. Fire Class A Bulkhead
h. Fire Class B Bulkhead
i. Fire Class C Bulkhead
j. Collision Bulkhead.
Q. What are the methods of reducing rolling?
Ans. Various Methods of Reducing Rolling are:-
a. Fin stabiliser
b. Bilge keel
Q. How much length does bilge keel extends to?
Q. What is an angle of loll?
Ans.
Angle of LOL: It is the angle at which the ship with initial negative Metacentric height will lie at rest in still water.
If the ship is further inclined to an angle more than angle of loll, the ship will sink.
Q. What is margin line?
Ans. Margin Line: It is the imaginary line which is drawn 75mm below the uppermost continuous deck. It denotes the limit, up to which vessel can be flooded/ loaded without sinking.
Q. What is block coefficient? If we say that block coefficient of one ship is 0.9 and the 0ther 0.95, what does it represent?
Ans. Block Coefficient:-It is the ratio of volume of displacement to the product of the length, breadth & draught.
Cb = Volume of displacement / (L x B x d)
When Block coefficient is more, it means Volume of displacement is more.
Q. What is the regulations for pumping out ER bilges in Special areas and outside special areas?
1. The ship should be proceeding en route from Point A to point B.
2. The oily mixture is processed through an oil filtering equipment.
3. The oily content of the effluent without dilution does not exceed more than 15ppm.
4. The oily mixture does not originate from cargo pump room bilges on oil tankers.
5. The oily mixture, in case of oil tankers, is not mixed with oil cargo residues.
Pumping out ER Bilges inside special area.
1. The ship should be proceeding en route from Point A to Point B.
2. The oily mixture is processed through an Oil filtering Equipment approved by the Administration.
3. The oil content of the effluent without dilution does not exceed more than 15ppm.
4. The oily mixture does not originate from Cargo pump room bilges on oil tankers.
5. The oily mixture in the case of oil tankers, is not mixed with oil cargo residues.
6. Any discharge into the sea of oil or oily mixtures from any ship shall be prohibited in Antarctic area.
Ans. As Per MARPOL Annex 1, Regulation 1, the special areas are:-
1. Mediterranean Sea
2. Baltic sea
3. Black sea
4. Red Sea
5. Gulf area
6. Gulf of Aden area
7. Antarctic area.
8. North West European Waters
9. Oman area of the Arabian sea