PSP Pilot Course relevant questions Flashcards
When backing into a pier against an offshore wind and tide with 2 tugs, which is the best arrangement of tugs?
a. place the most powerful tug aft
b. place the most powerful tug forward
c. order a 3rd tug to push amidship
d. with sternway, the wind generally will not affect the vessel’s movement
a. place the most powerful tug aft
When undocking a large tanker in following current and a ship is ahead in a berth, where should you place the most powerful tug?
a. in the stem
b. in the stern on a quarter bitt
c. on the quarter
d. on the bow
b. in the stern on a quarter bitt
When departing a pier and singling up to a short bight of line has what disadvantage?
a. it may be difficult to swing out at large angles
b. the ship’s bow remains close to the pier causing it to hit the dock
c. the tug will not be able to push off from the inside of the pier
d. the line will hold the entire ship into the dock
a. it may be difficult to swing the ship out at large angles
When undocking a large VLCC with a following current, when in doubt, what is the best course of action?
a. call for another tug to work amidships
b. wait for the next best tide
c. put the strongest tug on the quarter
d. put the strongest tug on the bow
b. wait for the next best tide
When getting underway with a very large ship, how can you swing the ship most effectively?
a. 1 tug pushing on the inside bow with more power than the 2nd tug pushing on the same side
b. 2 tugs pushing on the bow while the ship is going astern
c. 1 tug pulling on a line from the stem and 1 tug
d. 2 tugs pushing on the quarter while the ship is going ahead
b. 2 tugs pushing on the bow while the ship is going astern
When maneuvering astern, dredging an anchor will keep the bow of a ship from falling off in the wind.
a. true
b. false
a. true
When leaving port and singling up mooring lines, one should generally.
a. take in all springs and headlines at once
b. single up on a short line
c. single up with the bow and stern lines last and take in the spring lines first
d. take in all spring lines last and leave the offshore bow and stern lines
b. single up on a short line
When docking VLCCs, at what speed/s does the Doppler reading become unreliable?
a. less than 3 knots
b. less than 2 knots
c. less than 0.5 knots
d. less than 1 knot
d. less than 1 knot
Motion is perceived through constant observation on the ship. In most cases you can’t move a ship sideways without having what 3 components of motion?
a. sideways, fore & aft, turning
b. inertia, resistance, force
c. lateral, longitudinal, rotational
d. up, down, all around
c. lateral, longitudinal, rotational
Anything that exerts a force (weight on line/anchor chain, landing on a fender, tug) at a specific point will alter the position of the ships pivot point causing it to move towards the point where the force is exerted. How far toward that point is a matter of proportion or ratio between the amount of force and the ship’s inertia.
a. true
b. false
a. true
Calculate steering lever (distance from rudder to pivot point)
Steering Lever
(initial) = (L-B)
(under speed) = 3/4 (L-B)
Magnitude of wind force
wind-force (in pounds) = 0.004 x W x v2
W = windage in square feet
v = speed in knots
Calculating W
W (abeam) = LOA x D - LBP x mean draft
W (bow) = B x D - B x draft forward
LOA = length overall
LBP = length between perpendiculars
B = breadth, molded
D = depth, molded
25 knot wind-force calculation
70,000 dwt ship
drafts 16 feet forward, 26 feet aft
LOA 800 feet
LBP 765 feet
B 115 feet
D 56 feet
W (abeam) = 800 x 56 - 765 x 21
W = 28,735 sq ft
W (bow) = 115 x 56 - 115 x 16
W = 4,600 sq ft
wind-force (abeam) = 0.004 x 28,735 x 252 = 71,838 lbs = 36T
wind-force (bow) = 0.004 x 4,600 x 252 = 11,500 lbs = 5.75 (6T)
Magnitude of current force on beam
C = f x L x d x v2
C=current load in short tons
L=length in feet at waterline
d=mean draft
v=current speed in knots
f=UKC factor depending on water depth to draft ratio. water depth 1.1 x draft, f=0.0036. water depth 2 x draft, f=0.0018. water depth 3 x draft, f=0.0015
Current force calculation
70,000 dwt ship
length at waterline 790 feet
depth of water 46 feet
mean draft 21 feet
C (1 knot current) = 0.0018 x 790 x 21 x 12 = 29.9 (30T)
C (2 knot current) = 0.0018 x 790 x 21 x 22 = 119.5 (120T)
C (3 knot current) = 0.0018 x 790 x 21 x 32 = 268.8 (270T)