1 Sea Pressure

1.1 Total pressure

1.1.1 The external pressure P_ex at any load point of the hull, in kN/m², for the static (S) design load scenarios, is to be taken as:

P_ex = P_S but not less than 0.

The total pressure P_ex at any load point of the hull for the static plus dynamic (S+D) design load scenarios, is to be derived from each dynamic load case and is to be taken as:

P_ex = P_S + P_W but not less than 0.

where:

P_S : Hydrostatic pressure, in kN/m², defined in [1.2].

P_W : Wave pressure, in kN/m², is defined in [1.3].

1.2 Hydrostatic pressure

1.2.1 The hydrostatic pressure, P_S at any load point, in kN/m², is obtained from Table 1. See also Figure 1.

Table 1 : Hydrostatic pressure, P_S

Location	*Hydrostatic Pressure, P_S, in kN/m²*
z ≤ T_LC	ρ g (T_LC – z)
z > T_LC	0

Figure 1 : Hydrostatic pressure, P_S

1.3 External dynamic pressures for strength assessment

1.3.1 General

The hydrodynamic pressures for each dynamic load case defined in Ch 4, Sec 2, [2] are defined in [1.3.2] to [1.3.8].

1.3.2 Hydrodynamic pressures for HSM load cases

The hydrodynamic pressures, P_W, for HSM-1 and HSM-2 load cases, at any load point, in kN/m², are to be obtained from Table 2. See also Figure 2 and Figure 3.

Table 2 : Hydrodynamic pressures for HSM load cases

	Wave pressure, in kN/m²
Load case	z ≤ T_LC	T_LC < z ≤ h_W + T_LC	z > h_W + T_LC
HSM-1	P_W = max (–P_HS, ρg (z – T_LC))	P_W = P_W,WL - ρg(z - T_LC)	P_W = 0.0
HSM-2	P_W = max (P_HS, ρg (z – T_LC))	P_W = P_W,WL - ρg(z - T_LC)	P_W = 0.0

where:

f_nl : Coefficient considering non-linear effects, to be taken as:

For extreme sea loads design load scenario:
- f_nl = 0.7 at f_xL = 0
- f_nl = 0.9 at f_xL = 0.3
- f_nl = 0.9 at f_xL = 0.7
- f_nl = 0.6 at f_xL = 1
For ballast water exchange design load scenario:
- f_nl = 0.85 at f_xL = 0
- f_nl = 0.95 at f_xL = 0.3
- f_nl = 0.95 at f_xL = 0.7
- f_nl = 0.80 at f_xL = 1

Intermediate values are obtained by linear interpolation.

f_yz : Girth distribution coefficient, to be taken as:

f_h : Coefficient to be taken as:

f_h = 3.0(1.21 – 0.66 f_T)

k_a : Amplitude coefficient in the longitudinal direction of the ship, to be taken as:

for f_xL < 0.15
k_a = 1.0 for 0.15 ≤ f_xL < 0.7
for f_xL ≥ 0.7

λ : Wave length of the dynamic load case, in m, to be taken as:

λ = 0.6(1 + f_T)L

k_p : Phase coefficient to be obtained from Table 3. Intermediate values are to be interpolated.

Table 3 : k_p values for HSM load cases

f_xL	0	0.3 – 0.1 f_T	0.35 – 0.1 f_T	0.8 – 0.2 f_T	0.9 – 0.2 f_T	1.0
k_p	–0.25 f_T (1 + f_yB)	-1	1	1	-1	-1

Figure 2 : Transverse distribution amidships of dynamic pressure for HSM-1, HSA-1 and FSM-1 load cases

Figure 3 : Transverse distribution amidships of dynamic pressure for HSM-2, HSA-2 and FSM-2 load cases

1.3.3 Hydrodynamic pressures for HSA load cases

The hydrodynamic pressures, P_W, for HSA-1 and HSA-2 load cases at any load point, in kN/m², are to be obtained from Table 4. See also Figure 2 and Figure 3.

Table 4 : Hydrodynamic pressures for HSA load cases

	Wave pressure, in kN/m²
Load case	z ≤ T_LC	T_LC < z ≤ h_W + T_LC	z > h_W + T_LC
HSA-1	P_W = max(–P_HS, ρg(z – T_LC))	P_W = P_W,WL - ρg(z - T_LC)	P_W = 0.0
HSA-2	P_W = max(P_HS, ρg(z – T_LC))	P_W = P_W,WL - ρg(z - T_LC)	P_W = 0.0

where:

f_nl : Coefficient considering non-linear effects, to be taken as defined in [1.3.2].

f_yz : Girth distribution coefficient, to be taken as:

f_h : Coefficient to be taken as:

f_h = 2.4(1.21 – 0.66 f_T)

k_a : Amplitude coefficient in the longitudinal direction of the ship, to be taken as defined in [1.3.2].

λ : Wave length of the dynamic load case, in m, to be taken as:

λ = 0.6(1 + f_T)L

k_p : Phase coefficient to be obtained from Table 5. Intermediate values are to be interpolated.

Table 5 : k_p values for HSA load cases

f_xL	0	0.3 – 0.1 f_T	0.5 – 0.2 f_T	0.8 – 0.2 f_T	0.9 – 0.2 f_T	1.0
k_p	1.5 – f_T – 0.5 f_yB	-1	1	1	-1	-1

1.3.4 Hydrodynamic pressures for FSM load cases

The hydrodynamic pressures, P_W, for FSM-1 and FSM-2 load cases, at any load point, in kN/m², are to be obtained from Table 6. See also Figure 2 and Figure 3.

Table 6 : Hydrodynamic pressures for FSM load cases

	Wave pressure, in kN/m²
Load case	z ≤ T_LC	T_LC < z ≤ h_W + T_LC	z > h_W + T_LC
HSA-1	P_W = max(–P_FS, ρg(z – T_LC))	P_W = P_W,WL - ρg(z - T_LC)	P_W = 0.0
HSA-2	P_W = max(P_FS, ρg(z – T_LC))	P_W = P_W,WL - ρg(z - T_LC)	P_W = 0.0

where:

f_nl : Coefficient considering non-linear effects, to be taken as:

f_nl = 0.9 for extreme sea loads design load scenario.
f_nl = 0.95 for ballast water exchange design load scenarios.

f_yz : Girth distribution coefficient, to be taken as:

f_h : Coefficient to be taken as:

f_h = 2.6

k_a : Amplitude coefficient in the longitudinal direction of the ship, to be taken as:

k_a = 1 + (3.75 – 2 f_T)(1 – 5 f_xL)(1 – f_yB) for f_xL < 0.2
k_a = 1.0 for 0.2 ≤ f_xL < 0.9
k_a = 1 + 20(1 – f_yB) (f_xL – 0.9) for f_xL ≥ 0.9

λ : Wave length of the dynamic load case, in m, to be taken as:

λ = 0.6(1 + 2/3 f_T) L

k_p : Phase coefficient to be obtained from Table 7. Intermediate values are to be interpolated.

Table 7 : k_p values for FSM load cases

f_xL	0	0.35 – 0.1 f_T	0.5 – 0.2 f_T	0.75	0.8	1.0
k_p	– 0.75 – 0.25 f_yB	-1	1	1	-1	– 0.75 – 0.25 f_yB

1.3.5 Hydrodynamic pressures for BSR load cases

The wave pressures, P_W, for BSR-1 and BSR-2 load cases, at any load point, in kN/m², are to be obtained from Table 8. See also Figure 4 and Figure 5.

Table 8 : Hydrodynamic pressures for BSR load cases

	Wave pressure, in kN/m²
Load case	z ≤ T_LC	T_LC < z ≤ h_W + T_LC	z > h_W + T_LC
BSR-1P	P_W = max (P_BSR, ρg (_z - T_LC))	P_W = P_W,WL - ρg (z - T_LC)	P_W = 0.0
BSR-2P	P_W = max (- P_BSR, ρg (z - T_LC))
BSR-1S	P_W = max (P_BSR, ρg (z - T_LC))
BSR-2S	P_W = max (- P_BSR, ρg (z - T_LC))

where:

For BSR-1P and BSR-2P load cases.
For BSR-1S and BSR-2S load cases.

f_nl : Coefficient considering non-linear effect, to be taken as:

f_nl = 1 for extreme sea loads design load scenario.
f_nl = 1 for ballast water exchange design load scenarios.

λ : Wave length of the dynamic load case, in m, to be taken as:

Figure 4 : Transverse distribution of dynamic pressure for BSR-1P (left) and BSR-1S (right) load cases

Figure 5 : Transverse distribution of dynamic pressure for BSR-2P (left) and BSR-2S (right) load cases

1.3.6 Hydrodynamic pressures for BSP load cases The wave pressures, P_W, for BSP-1 and BSP-2 load cases, at any load point, in kN/m², are to be obtained from Table 9. See also Figure 6 and Figure 7.

Table 9: Hydrodynamic pressures for BSP load cases

	Wave pressure, in kN/m²
Load case	z ≤ T_LC	T_LC < z ≤ h_W + T_LC	z > h_W + T_LC
BSP-1P	P_W = max (P_BSP, ρg (_z - T_LC))	P_W = P_W,WL - ρg (z - T_LC)	P_W = 0.0
BSP-2P	P_W = max (- P_BSR, ρg (z - T_LC))
BSP-1S	P_W = max (P_BSR, ρg (z - T_LC))
BSP-2S	P_W = max (- P_BSR, ρg (z - T_LC))

where:

λ : Wave length of the dynamic load case, in m, to be taken as:

λ = 0.2(1 + 2 f_T)L

f_yz : Girth distribution coefficient, to be obtained from Table 10.

Table 10 : Girth distribution coefficient, f_yz for BSP load cases

Transverse position	BSP-1P - BSP-2P	BSP-1S - BSP-2S
y ≥ 0
y < 0

f_nl : Coefficient considering non-linear effect, to be taken as:

For extreme sea loads design load scenario:
- f_nl = 0.6 at f_xL = 0
- f_nl = 0.8 at f_xL = 0.3
- f_nl = 0.8 at f_xL = 0.7
- f_nl = 0.6 at f_xL = 1
For ballast water exchange design load scenario:
- f_nl = 0.6 at f_xL = 0
- f_nl = 0.8 at f_xL = 0.3
- f_nl = 0.8 at f_xL = 0.7
- f_nl = 0.6 at f_xL = 1

Intermediate values are obtained by linear interpolation.

Figure 6 : Transverse distribution of dynamic pressure for BSP-1P (left) and BSP-1S (right) load cases

Figure 7 : Transverse distribution of dynamic pressure for BSP-2P (left) and BSP-2S (right) load cases

1.3.7 Hydrodynamic pressures for OST load cases

The wave pressures, P_W, for OST-1 and OST-2 load cases, at any load point are to be obtained, in kN/m², from Table 11. See also Figure 8 and Figure 9.

Figure 8 : Transverse distribution of dynamic pressure amidships for OST-1P (left) and OST-1S (right) load cases

Figure 9 : Transverse distribution of dynamic pressure amidships for OST-2P (left) and OST-2S (right) load cases

Table 11 : Hydrodynamic pressures for OST load cases

	Wave pressure, in kN/m²
Load case	z ≤ T_LC	T_LC < z ≤ h_W + T_LC	z > h_W + T_LC
OST-1P	P_W = max (P_OST, ρg (z - T_LC))	P_W = P_W,WL - ρg (z - T_LC)	P_W = 0.0
OST-2P	P_W = max (- P_OST, ρg (z - T_LC))
OST-1S	P_W = max (P_OST, ρg (z - T_LC))
OST-2S	P_W = max (- P_OST, ρg (z - T_LC))

where:

f_yz : Girth distribution coefficient, to be obtained from Table 12.

f_nl : Coefficient considering non-linear effect, to be taken as:

f_nl = 0.8 for extreme sea loads design load scenario.
f_nl = 0.9 for ballast water exchange design load scenarios.

λ : Wave length of the dynamic load case, in m, to be taken as:

λ = 0.45 L

k_a : Amplitude coefficient in the longitudinal direction of the ship, to be obtained from Table 13.

k_p : Phase coefficient to be obtained from Table 14. Intermediate values are to be interpolated.

Table 12 : Girth distribution coefficient, f_yz for OST load cases

Transverse position	OST-1P - OST-2P	OST-1S - OST-2S
y ≥ 0
y < 0

Table 13 : k_a values for OST load cases

Transverse position	Longitudinal Position	OST-1P - OST-2P	OST-1S - OST-2S
y ≥ 0	f_xL ≤ 0.2	1.0 + 3.5(1 – f_yB) (1 – 5 f_xL)	1.0 + [3.5 – (4f_T – 0.5)f_yB](1 – 5 f_xL)
	0.2 < f_xL ≤ 0.8	1.0	1.0
	f_xL > 0.8	1.0	1.0 + 4 (1 – f_T) (5 f_xL – 4) f_yB
y < 0	f_xL ≤ 0.2	1.0 + [3.5 – (4 f_T – 0.5) f_yB] (1 – 5 f_xL)	1.0 + 3.5(1 – f_yB)(1 – 5 f_xL)
	0.2 < f_xL ≤ 0.8	1.0	1.0
	f_xL > 0.8	1.0 + 4(1 – f_T)(5 f_xL – 4) f_yB	1.0

Table 14 : k_p values for OST load cases

Transverse position	*f_xL*	OST-1P - OST-2P	OST-1S - OST-2S
y ≥ 0	0.0	1.0	1.0
	0.2	1.0	1.0 + (0.75 – 1.5 f_T) f_yB
	0.4	-1.0	– 1.0 + (1.75 – 0.5 f_T) f_yB
	0.5	-1.0	– 1.0 + (1.75 – 0.5 f_T) f_yB
	0.7	– 0.1 + (1.6 f_T – 1.5) f_yB	– 0.1 + (0.25 – 0.3 f_T) f_yB
	0.9	0.8 + 0.2 f_yB	0.8 – (0.9 f_T + 0.85) f_yB
	1.0	– 1.0 + f_yB	– 1.0 + (0.5 – 0.5 f_T) f_yB
y < 0	0.0	1.0	1.0
	0.2	1.0 + (0.75 – 1.5 f_T) f_yB	1.0
	0.4	– 1.0 + (1.75 – 0.5 f_T) f_yB	-1.0
	0.5	– 1.0 + (1.75 – 0.5 f_T) f_yB	-1.0
	0.7	– 0.1 + (0.25 – 0.3 f_T) f_yB	– 0.1 + (1.6f_T – 1.5)f_yB
	0.9	0.8 – (0.9 f_T + 0.85) f_yB	0.8 + 0.2 fyB
	1.0	– 1.0 + (0.5 – 0.5 f_T) f_yB	– 1.0 + f_yB

1.3.8 Hydrodynamic pressures for OSA load cases

The wave pressures, P_W, for OSA-1 and OSA-2 load cases, at any load point, in kN/m², are to be obtained from Table 15. See also Figure 10 and Figure 11.

Table 15 : Hydrodynamic pressures for OSA load cases

	Wave pressure, in kN/m²
Load case	z ≤ T_LC	T_LC < z ≤ h_W + T_LC	z > h_W + T_LC
OSA-1P	P_W = max (P_OSA, ρg (z - T_LC))	P_W = P_W,WL - ρg (z - T_LC)	P_W = 0.0
OSA-2P	P_W = max (- P_OSA, ρg (z - T_LC))
OSA-1S	P_W = max (P_OSA, ρg (z - T_LC))
OSA-2S	P_W = max (- P_OSA, ρg (z - T_LC))

where:

λ : Wave length of the dynamic load case, in m, to be taken as:

λ = 0.70 L

f_nl : Coefficient considering non-linear effect, to be taken as:

For extreme sea loads design load scenario:
- f_nl = 0.5 at f_xL = 0
- f_nl = 0.8 at f_xL = 0.3
- f_nl = 0.8 at f_xL = 0.7
- f_nl = 0.6 at f_xL = 1
For ballast water exchange design load scenario:
- f_nl = 0.75 at f_xL = 0
- f_nl = 0.9 at f_xL = 0.3
- f_nl = 0.9 at f_xL = 0.7
- f_nl = 0.8 at f_xL = 1

Intermediate values are obtained by linear interpolation.

f_yz : Girth distribution coefficient, to be obtained from Table 16.

k_a : Amplitude coefficient in the longitudinal direction of the ship, to be obtained from Table 17.

k_p : Phase coefficient to be obtained from Table 18. Intermediate values are to be interpolated.

Table 16 : Girth distribution coefficient, f_yz for OSA load cases

Transverse position	OSA-1P - OSA-2P	OSA-1S - OSA-2S
y ≥ 0
y < 0

Table 17 : k_a values for OSA load cases

Transverse position	Longitudinal position	OSA-1P - OSA-2P	OSA-1S - OSA-2S
y ≥ 0	f_xL ≤ 0.2	1.0 + 3 (2 – f_T) (1 – 5 f_xL) (1 – f_yB)	1.0 + 3 (2 – f_T) (1 – 5 f_xL) + {(28 f_xL – 5) + 3 f_T(1 – 5 f_xL)} f_yB
	0.2 < f_xL ≤ 0.5	1.0	1.0 + (1 – 2 f_xL) f_yB
	0.5 < f_xL ≤ 0.8	1.0	1.0 + 1.5(2 f_xL – 1) f_yB
	f_xL > 0.8	1.0 + (f_xL – 0.8) (1 – f_yB) A	1.0 + {1.5(2 f_xL – 1) – (f_xL – 0.8) A}f_yB + (f_xL – 0.8) A
y < 0	f_xL ≤ 0.2	1.0 + 3 (2 – f_T) (1 – 5 f_xL) + {(28 f_xL – 5) + 3 f_T(1 – 5 f_xL)} f_yB	1.0 + 3 (2 – f_T) (1 – 5 f_xL) (1 – f_yB)
	0.2 < f_xL ≤ 0.5	1.0 + (1 – 2 f_xL) f_yB	1.0
	0.5 < f_xL ≤ 0.8	1.0 + 1.5(2 f_xL – 1) f_yB	1.0
	f_xL > 0.8	1.0 + {1.5(2 f_xL – 1) – (f_xL – 0.8) A}f_yB + (f_xL – 0.8) A	1.0 + (f_xL – 0.8) (1 – f_yB) A
where: A = 22 – 15f_T + 3[22(f_xL – 0.8)–0.25(2 – f_T)]

Figure 10 : Transverse distribution of dynamic pressure amidships for OSA-1P (left) and OSA-1S (right) load cases

Figure 11 : Transverse distribution of dynamic pressure amidships for OSA-2P (left) and OSA-2S (right) load cases

Table 18 : k_p values for OSA load cases

Transverse position	*f_xL*	OSA-1P; OSA-2P	OSA-1S; OSA-2S
y ≥ 0	0.0	0.75 – 0.5 f_yB	0.75
	0.2	f_T – 0.25 + (1.25 – f_T) f_yB	f_T – 0.25 + (0.35 f_T – 0.47) f_yB
	0.4	1.0	1.0 + (2.7 f_T – 3.2) f_yB
	0.5	1.25 – 0.5 f_T + (0.5 f_T – 0.25)f_yB	1.25 – 0.5 f_T + (2.7 f_T – 3.2) f_yB
	0.6	1.5 – f_T + (f_T – 1.07) f_yB	1.5 – f_T + (2.68 f_T – 3.19) f_yB
	0.85	0.5 f_T – 1.25 + (0.25 – 0.5 f_T) f_yB	0.5 f_T – 1.25 + (0.2 – 0.1 f_T) f_yB
	1.0	0.5 f_T – 1.25 + (0.25 – 0.5 f_T) f_yB	0.5 f_T – 1.25 + (0.2 – 0.1 f_T) f_yB
y < 0	0.0	0.75	0.75 – 0.5 f_yB
	0.2	f_T – 0.25 + (0.35 f_T – 0.47) f_yB	f_T – 0.25 + (1.25 – f_T) f_yB
	0.4	1.0 + (2.7 f_T – 3.2) f_yB	1.0
	0.5	1.25 – 0.5 f_T + (2.7 f_T – 3.2) f_yB	1.25 – 0.5 f_T + (0.5 f_T – 0.25)f_yB
	0.6	1.5 – f_T + (2.68 f_T – 3.19) f_yB	1.5 – f_T + (f_T – 1.07) f_yB
	0.85	0.5 f_T – 1.25 + (0.2 – 0.1 f_T) f_yB	0.5 f_T – 1.25 + (0.25 – 0.5 f_T) f_yB
	1.0	0.5 f_T – 1.25 + (0.2 – 0.1 f_T) f_yB	0.5 f_T – 1.25 + (0.25 – 0.5 f_T) f_yB

1.3.9 Envelope of dynamic pressure

The envelope of dynamic pressure at any point, P_ex-max, is to be taken as the greatest pressure obtained from any of the load cases determined by [1.3.2] to [1.3.8].

1.4 External dynamic pressures for fatigue assessments

1.4.1 General

The external pressure P_ex at any load point of the hull for the fatigue static plus dynamic (F:S+D) design load scenario, is to be derived for each fatigue dynamic load case and is to be taken as:

P_ex = P_S + P_W but not less than 0.

where:

P_S : Hydrostatic pressure, in kN/m², defined in[1.2].

P_W : Hydrodynamic pressure, in kN/m², is defined in [1.4.2] to [1.4.6].

1.4.2 Hydrodynamic pressures for HSM load cases

The hydrodynamic pressures, P_W, for load cases HSM-1 and HSM-2, at any load point, in kN/m², are to be obtained from Table 19.

Table 19 : Hydrodynamic pressures for HSM load cases

	Wave pressure, in kN/m²
Load case	z ≤ T_LC	T_LC < z ≤ 2h_w + T_LC	z > 2h_w + T_LC
HSM-1	P_w = max (–P_HS, ρg(z – T_LC))		P_W = 0.0
HSM-2	P_w = max (P_HS, ρg(z – T_LC))		P_W = 0.0

where:

f_yz : Girth distribution coefficient, to be taken as:

f_h : Coefficient to be taken as:

f_h = 2.75 (1.21 – 0.66 f_T)

f_p : Coefficient to be taken as:

f_p = f_fa[(0.21 + 0.02 f_T) + (6 – 4 f_T) L × 10^–5]

k_a : Amplitude coefficient in the longitudinal direction of the ship, to be taken as:

ka = 1 + 3 f_T – (1 + f_T) f_yB + [5 (1 + f_T) f_yB – 15 f_T] f_xL for f_xL < 0.2
k_a = 1.0 for 0.2 ≤ f_xL < 0.6
k_a = 1 + (f_xL – 0.6) [(13.5 – 3.5 f_T) f_yB + (14.5 f_T – 17) + 40(1 – f_yB) (f_xL – 0.6)] for f_xL ≥ 0.6

λ : Wave length of the dynamic load case, in m, to be taken as:

λ = 0.6 (1 + f_T) L

k_p : Phase coefficient to be obtained from Table 20. Intermediate values are to be interpolated.

Table 20 : k_p values for HSM load cases

*f_xL*	*k_P*
0	(1.0 – f_T) + (0.5 – f_T) f_yB
0.3 – 0.1 f_T	-1
0.5 – 0.2 f_T	1
0.9 – 0.4 f_T	1
0.9 – 0.2 f_T	-1
1.0	-1

1.4.3 Hydrodynamic pressures for FSM load cases

The hydrodynamic pressures, P_W, for FSM-1 and FSM-2 load cases, at any load point, in kN/m², are to be obtained from Table 21.

Table 21 : Hydrodynamic pressures for FSM load cases

	Wave pressure, in kN/m²
Load case	z ≤ T_LC	T_LC < z ≤ 2h_w + T_LC	z > 2h_w + T_LC
FSM-1	P_w = max (–P_FS, ρg(z – T_LC))		P_W = 0.0
FSM-2	P_W = max (P_FS, ρg(z – T_LC))		P_W = 0.0

where:

f_yz : Girth distribution coefficient, to be taken as:

f_h : Coefficient to be taken as:

f_h = 2.6

f_p : Coefficient to be taken as:

f_p = f_fa[(0.21 + 0.02 f_T) + (6 – 4 f_T) L × 10^–5]

k_a : Amplitude coefficient in the longitudinal direction of the ship, to be taken as:

k_a = 1 + (3.5 – 2 f_T)(1 – 5 f_xL)(1 – f_yB) for f_xL < 0.2
k_a = 1.0 for 0.2 ≤ f_xL < 0.9
k_a = 1 + 15(1 – f_yB)(f_xL – 0.9) for f_xL ≥ 0.9

λ : Wave length of the dynamic load case, in m, to be taken as:

k_p : Phase coefficient to be obtained from Table 22. Intermediate values are to be interpolated.

Table 22 : k_p values for FSM load cases

*f_xL*	*k_P*
0	– 0.75 – 0.25 f_yB
0.35 – 0.1 f_T	-1
0.5 – 0.2 f_T	1
0.75	1
0.9 – 0.1 f_T	-1
1.0	– 0.5 – 0.5 f_yB

1.4.4 Hydrodynamic pressures for BSR load cases

The hydrodynamic pressures, P_W, for BSR-1 and BSR-2 load cases, at any load point, in kN/m², are to be obtained from Table 23.

Table 23 : Hydrodynamic pressures for BSR load cases

	Wave pressure, in kN/m²
Load case	z ≤ T_LC	T_LC < z ≤ 2 h_W + T_LC	z > 2 h_W + T_LC
BSR-1P	P_W = max (P_BSR, ρg(z - T_LC))		P_W = 0.0
BSR-2P	P_W = max (- P_BSR, ρg(z - T_LC))
BSR-1S	P_W = max (P_BSR, ρg(z - T_LC))
BSR-2S	P_W = max (- P_BSR, ρg(z - T_LC))

where:

For BSR-1P and BSR-2P load cases.

For BSR-1S and BSR-2S load cases.

f_p : Coefficient to be taken as:

f_p = f_fa[(0.21 + 0.04 f_T) – (12 f_T – 2) B × 10^–4]

λ : Wave length of the dynamic load case, in m, to be taken as:

1.4.5 Hydrodynamic pressures for BSP load cases

The wave pressures, P_W, for BSP-1 and BSP-2 load cases, at any load point, in kN/m², are to be obtained from Table 24.

Table 24 : Hydrodynamic pressures for BSP load cases

	Wave pressure, in kN/m²
Load case	z ≤ T_LC	T_LC < z ≤ 2 h_W + T_LC	z > 2 h_W + T_LC
BSP-1P	P_W = max (P_BSP, ρg(z - T_LC))		P_W = 0.0
BSP-2P	P_W = max (- P_BSP, ρg(z - T_LC))
BSP-1S	P_W = max (P_BSP, ρg(z - T_LC))
BSP-2S	P_W = max (- P_BSP, ρg(z - T_LC))

where:

λ : Wave length of the dynamic load case, in m, to be taken as:

λ = 0.2(1 + 2 f_T)L

f_p : Coefficient to be taken as:

f_p = f_fa[0.2 + (8 + 16 f_T) × 10^–3]

f_yz : Girth distribution coefficient, to be obtained from Table 25.

Table 25 : Girth distribution coefficient, f_yz for BSP load cases

Transverse position	BSP-1P - BSP-2P	BSP-1S - BSP-2S
y ≥ 0
y < 0

1.4.6 Hydrodynamic pressures for OST load cases

The wave pressures, P_W, for OST-1 and OST-2 load cases, at any load point, in kN/m², are to be obtained from Table 26.

Table 26 : Hydrodynamic pressures for OST load cases

	Wave pressure, in kN/m²
Load case	z ≤ T_LC	T_LC < z ≤ 2 h_W + T_LC	z > 2 h_W + T_LC
OST-1P	P_W = max (P_OST, ρg(z - T_LC))		P_W = 0.0
OST-2P	P_W = max (- P_OST, ρg(z - T_LC))
OST-1S	P_W = max (P_OST, ρg(z - T_LC))
OST-2S	P_W = max (- P_OST, ρg(z - T_LC))

where:

f_yz : Girth distribution coefficient, to be obtained from Table 27.

Table 27 : Girth distribution coefficient, f_yz for OST load cases

Transverse position	OST-1P - OST-2P	OST-1S - OST-2S
y ≥ 0
y < 0

f_p : Coefficient to be taken as:

f_p = f_fa[(0.25 – 0.02 f_T) + (12 f_T – 9) B × 10^–4]

λ : Wave length of the dynamic load case, in m, to be taken as:

λ = 0.45 L

k_a : Amplitude coefficient in the longitudinal direction of the ship, to be obtained from Table 28.

k_p : Phase coefficient to be obtained from Table 29. Intermediate values are to be interpolated.

Table 28 : k_a values for OST load cases

Transverse position	Longitudinal Position	OST-1P - OST-2P	OST-1S - OST-2S
y ≥ 0	f_xL ≤ 0.2	1.0 + {(3.5 – 2 f_T) + (10 f_T – 17.5)f_xL} (1 – f_yB)	1.0 + (3.5 – 2 f_T – 1.5 f_yB) + (10 f_T – 17.5 + 7.5 f_yB)f_xL
	0.2 < f_xL ≤ 0.8	1.0	1.0
	f_xL > 0.8	1.0	1.0 + 2(1 – f_T)(5f_xL – 4)f_yB
y < 0	f_xL ≤ 0.2	1.0 + (3.5 – 2 f_T – 1.5 f_yB) + (10 f_T – 17.5 + 7.5 f_yB)f_xL	1.0 + {(3.5 – 2 f_T) + (10 f_T – 17.5)f_xL}(1 – f_yB)
	0.2 < f_xL ≤ 0.8	1.0	1.0
	f_xL > 0.8	1.0 + 2(1 – f_T)(5f_xL – 4)f_yB	1.0

Table 29 : k_p values for OST load cases

Transverse position	*f_xL*	OST-1P - OST-2P	OST-1S - OST-2S
y ≥ 0	0.0	1.0	1.0 + (0.5 – f_T) f_yB
	0.2	1.0	1.0 + 3(0.5 – f_T)f_yB
	0.4	-1.0	(2.7 – 2.4 f_T) f_yB – 1
	0.5	-1.0	(2.8 – 2.6 f_T) f_yB – 1
	0.7	(f_T – 0.62) f_yB – 0.38	(2.38 – 3 f_T) f_yB – 0.38
	0.9	0.24 + 0.76 f_yB	0.24 – (0.24 + f_T) f_yB
	1.0	– 1.0 + 0.5 f_yB	–1.0
y < 0	0.0	1.0 + (0.5 – f_T) f_yB	1.0
	0.2	1.0 + 3(0.5 – f_T)f_yB	1.0
	0.4	(2.7 – 2.4 f_T) f_yB – 1	–1.0
	0.5	(2.8 – 2.6 f_T) f_yB – 1	–1.0
	0.7	(2.38 – 3 f_T) f_yB – 0.38	(f_T – 0.62) f_yB – 0.38
	0.9	0.24 – (0.24 + f_T) f_yB	0.24 + 0.76 f_yB
	1.0	–1.0	– 1.0 + 0.5 f_yB

1 Sea Pressure

Table 1 : Hydrostatic pressure, PS

Table 2 : Hydrodynamic pressures for HSM load cases

Table 3 : kp values for HSM load cases

Table 4 : Hydrodynamic pressures for HSA load cases

Table 5 : kp values for HSA load cases

Table 6 : Hydrodynamic pressures for FSM load cases

Table 7 : kp values for FSM load cases

Table 8 : Hydrodynamic pressures for BSR load cases

Table 9: Hydrodynamic pressures for BSP load cases

Table 10 : Girth distribution coefficient, fyz for BSP load cases

Table 11 : Hydrodynamic pressures for OST load cases

Table 12 : Girth distribution coefficient, fyz for OST load cases

Table 13 : ka values for OST load cases

Table 14 : kp values for OST load cases

Table 15 : Hydrodynamic pressures for OSA load cases

Table 16 : Girth distribution coefficient, fyz for OSA load cases

Table 17 : ka values for OSA load cases

Table 18 : kp values for OSA load cases

Table 19 : Hydrodynamic pressures for HSM load cases

Table 20 : kp values for HSM load cases

Table 21 : Hydrodynamic pressures for FSM load cases

Table 22 : kp values for FSM load cases

Table 23 : Hydrodynamic pressures for BSR load cases

Table 24 : Hydrodynamic pressures for BSP load cases

Table 25 : Girth distribution coefficient, fyz for BSP load cases

Table 26 : Hydrodynamic pressures for OST load cases

Table 27 : Girth distribution coefficient, fyz for OST load cases

Table 28 : ka values for OST load cases

Table 29 : kp values for OST load cases

Table 1 : Hydrostatic pressure, P_S

Table 3 : k_p values for HSM load cases

Table 5 : k_p values for HSA load cases

Table 7 : k_p values for FSM load cases

Table 10 : Girth distribution coefficient, f_yz for BSP load cases

Table 12 : Girth distribution coefficient, f_yz for OST load cases

Table 13 : k_a values for OST load cases

Table 14 : k_p values for OST load cases

Table 16 : Girth distribution coefficient, f_yz for OSA load cases

Table 17 : k_a values for OSA load cases

Table 18 : k_p values for OSA load cases

Table 20 : k_p values for HSM load cases

Table 22 : k_p values for FSM load cases

Table 25 : Girth distribution coefficient, f_yz for BSP load cases

Table 27 : Girth distribution coefficient, f_yz for OST load cases

Table 28 : k_a values for OST load cases

Table 29 : k_p values for OST load cases