large is the roll amplitude when resonance occurs?
Question 3: Assuming that the total mass moment of inertia is reduced by 10% , whereas the
displacement keeps unchanged. To maintain the natural period a constant, how large should be the
SHIP MANOEUVRING AND SEAKEEPING
船舶操纵与耐波
SHIP MANOEUVRING AND SEAKEEPING
(Lectures by Professor Zou Zaojian, Shanghai Jiao Tong University)
HOME EXERCISES
1. For three ships, Ship A, Ship B and Ship C, it is known that
transverse metacentric height? In this case, assuming that the damping coefficient Nθ keeps unchanged,
how large is the roll amplitude when resonance occurs?
Yδ′
Nδ′
78 -3467 -2640 1282
Ship B -12608 -16630 -461 -2900 -771 4330 326 -6570 -2959 1435
Ship C -11420 -15338 -576 -3074 -714 4842 -523 -5544 -3168 1402
Ship A (Mariner) Ship B (Series 60) Ship C (Tanker)
m′ ×106
7974 11432 14622
m′xG′ ×106
-176 57 365
Iz′ ×106
428 573 766
The linear hydrodynamic derivatives are obtained from captive model tests as shown ihe Ship A dynamically stable or unstable? Why? Question 2: Compare the turning ability and the dynamic stability of Ship B and Ship C.
Question 3: How large is the nondimensional steady turning diameter of Ship A with rudder angle
δ0 = 18ο (V0 = V ≈ U )?
2. A ship has natural period Tθ = 13 s, transverse metacentric height h (GM ) = 1 m, nondimensional coefficient µθ = 0.10 . (It is known that for deep water k = ω 2 / g , where k is the wave number and ω is the wave frequency)
Question 1: At what wavelength λ will the roll resonance occur? Question 2: If the maximal wave slope α0 = 0.534λ −1/4 (radian), the coefficient Kθ = 0.73 , how
nondimensional forms in the table below (the values are to be multiplied by 10−6 ):
Yv&′
Yv′
Nr′&
Nr′
Yr&′
Ship A -7488 -11593 -444 -2083 -144
Yr′
3529
Nv′&
Nv′