Clasification Society Rulefinder 2020 - Version 9.33 - Fix
Common Structural Rules - Common Structural Rules for Bulk Carriers and Oil Tankers, January 2019 - Part 1 General Hull Requirements - Chapter 4 Loads - Section 2 Dynamic Load Cases - 2 Dynamic Load Cases for Strength Assessment

2 Dynamic Load Cases for Strength Assessment

2.1 Description of dynamic load cases

2.1.1 Table 1 to Table 3 describe the ship motions responses and the global loads corresponding to each dynamic load case to be considered for the strength assessment.

Table 1 : Ship responses for HSM, HSA and FSM load cases - Strength assessment

Loadcase HSM-1 HSM-2 HSA-1 HSA-2 FSM-1 FSM-2
EDW HSM HSA FSM
Heading Head Head Following
Effect Max. bending moment Max. vertical acceleration Max. bending moment
VWBM Sagging Hogging Sagging Hogging Sagging Hogging
VWSF

Negative–aft

Positive–fore

Positive–aft

Negative–fore

Negative–aft

Positive–fore

Positive–aft

Negative–fore

Negative–aft

Positive–fore

Positive–aft

Negative–fore
HWBM - - - - - -
TM - - - - - -
Surge To stern To bow To stern To bow To bow To stern
asurge
Sway - - - - - -
asway - - - - - -
Heave Down Up Down Up - -
aheave - -
Roll - - - - - -
aroll - - - - - -
Pitch Bow down Bow up Bow down Bow up Bow up Bow down
apitch

Table 2 : Ship responses for BSR and BSP load cases - Strength assessment

Loadcase BSR-1P BSR-2P BSR-1S BSR-2S BSP-1P BSP-2P BSP-1S BSP-2S
EDW BSR BSR BSP BSP
Heading Beam Beam
Effect Max. roll Max. pressure at waterline
VWBM Sagging Hogging Sagging Hogging Sagging Hogging Sagging Hogging
VWSF

Negative–aft

Positive–fore

Positive–aft

Negative–fore

Negative–aft

Positive–fore

Positive–aft

Negative–fore

Negative–aft

Positive–fore

Positive–aft

Negative–fore

Negative–aft

Positive–fore

Positive–aft

Negative–fore
HWBM Stbd tensile Port tensile Port tensile Stbd tensile Stbd tensile Port tensile Port tensile Stbd tensile
TM - - - - - - - -
Surge - - - - - - - -
asurge - - - - - - - -
Sway To starboard To portside To portside To starboard To portside To starboard To starboard To portside
asway
Heave Down Up Down Up Down Up Down Up
aheave
Roll Portside down Portside up Starboard down Starboard up Portside down Portside up Starboard down Starboard up
aroll
Pitch - - - - Bow down Bow up Bow down Bow up
apitch - - - -

Table 3 : Ship responses for OST and OSA load cases - Strength assessment

Loadcase OST-1P OST-2P OST-1S OST-2S OSA-1P OSA-2P OSA-1S OSA-2S
EDW OST OSA
Heading Oblique Oblique
Effect Max. torsional moment Max. pitch acceleration
VWBM Sagging Hogging Sagging Hogging Hogging Sagging Hogging Sagging
VWSF

Negative–aft

Positive–fore

Positive–aft

Negative–fore

Negative–aft

Positive–fore

Positive–aft

Negative–fore

Positive–aft

Negative–fore

Negative–aft

Positive–fore

Positive–aft

Negative–fore

Negative–aft

Positive–fore

HWBM Port tensile Stbd tensile Stbd tensile Port tensile Stbd tensile Port tensile Port tensile Stbd tensile
TM
Surge To bow To stern To bow To stern To bow To stern To bow To stern
asurge
Sway - - - - To portside To starboard To starboard To portside
asway - - - -
Heave Down Up Down Up Up Down Up Down
aheave
Roll Portside down Portside up Starboard down Starboard up Portside down Portside up Starboard down Starboard up
aroll
Pitch Bow up Bow down Bow up Bow down Bow up Bow down Bow up Bow down
apitch

2.2 Load combination factors

2.2.1 The load combinations factors, LCFs for the global loads and inertia load components for strength assessment are defined in:

Table 4 : LCFs for HSM, HSA and FSM load cases.

Table 5 : LCFs for BSR and BSP load cases.

Table 6 : LCFs for OST and OSA load cases.

Table 4 : Load combination factors, LCFs for HSM, HSA and FSM load cases - Strength assessment

Load component LCF HSM-1 HSM-2 HSA-1 HSA-2 FSM-1 FSM-2
Hull girder loads MWV CWV -1 1 -0.7 0.7 -0.4fT - 0.6 0.4fT + 0.6
QWV CQW -1.0flp 1.0flp -0.6flp 0.6flp -1.0flp 1.0flp
MWH CWH 0 0 0 0 0 0
MWT CWT 0 0 0 0 0 0
Longitudinal accelerations asurge CXS 0.3 – 0.2fT 0.2fT - 0.3 0.2 -0.2 0.2 – 0.4fT 0.4fT - 0.2
apitch-x CXP -0.7 0.7 -0.4fT - 0.4 0.4fT + 0.4 0.15 -0.15
gsinϕ CXG 0.6 -0.6 0.4fT + 0.4 -0.4fT - 0.4 -0.2 0.2
Transverse accelerations asway CYS 0 0 0 0 0 0
aroll-y CYR 0 0 0 0 0 0
gsinθ CYG 0 0 0 0 0 0
Vertical accelerations aheave CZH 0.5fT - 0.15 0.15 – 0.5fT 0.4fT - 0.1 0.1 – 0.4fT 0 0
aroll-z CZR 0 0 0 0 0 0
apitch-z CZP -0.7 0.7 -0.4fT - 0.4 0.4fT + 0.4 0.15 -0.15

Table 5 : Load combination factors, LCFs for BSR and BSP load cases - Strength assessment

Load component LCF BSR-1P BSR-2P BSR-1S BSR-2S
Hull girder loads MWV CWV 0.1 – 0.2fT 0.2fT - 0.1 0.1 – 0.2fT 0.2fT - 0.1
QWV CQW (0.1 – 0.2fT) flp (0.2fT - 0.1) flp (0.1 – 0.2fT) flp (0.2fT - 0.1) flp
MWH CWH 1.2 – 1.1fT 1.1fT – 1.2 1.1fT – 1.2 1.2 – 1.1fT
MWT CWT 0 0 0 0
Longitudinal accelerations asurge CXS 0 0 0 0
apitch-x CXP 0 0 0 0
gsinϕ CXG 0 0 0 0
Transverse accelerations asway CYS 0.2 – 0.2fT 0.2fT - 0.2 0.2fT - 0.2 0.2 – 0.2fT
aroll-y CYR 1 -1 -1 1
gsinθ CYG -1 1 1 -1
Vertical accelerations aheave CZH 0.7 – 0.4fT 0.4fT - 0.7 0.7 – 0.4fT 0.4fT - 0.7
aroll-z CZR 1 -1 -1 1
apitch-z CZP 0 0 0 0

Load component LCF BSP-1P BSP-2P BSP-1S BSP-2S
Hull girder loads MWV CWV 0.3 – 0.8fT 0.8fT - 0.3 0.3 – 0.8fT 0.8fT - 0.3
QWV CQW (0.3 – 0.8fT) flp (0.8fT - 0.3) flp (0.3 – 0.8fT) flp (0.8fT - 0.3) flp
MWH CWH 0.7 – 0.7fT 0.7fT - 0.7 0.7fT - 0.7 0.7 – 0.7fT
MWT CWT 0 0 0 0
Longitudinal accelerations asurge CXS 0 0 0 0
apitch-x CXP 0.1 – 0.3fT 0.3fT - 0.1 0.1 – 0.3fT 0.3fT - 0.1
gsinϕ CXG 0.3fT - 0.1 0.1 – 0.3fT 0.3fT - 0.1 0.1 – 0.3fT
Transverse accelerations asway CYS -0.9 0.9 0.9 -0.9
aroll-y CYR 0.3 -0.3 -0.3 0.3
gsinθ CYG -0.2 0.2 0.2 -0.2
Vertical accelerations aheave CZH 1 -1 1 -1
aroll-z CZR 0.3 -0.3 -0.3 0.3
apitch-z CZP 0.1 – 0.3fT 0.3fT - 0.1 0.1 – 0.3fT 0.3fT - 0.1

Table 6 : Load combination factors, LCFs for OST and OSA load cases - Strength assessment

Load component LCF OST-1P OST-2P OST-1S OST-2S
Hull girder loads MWV CWV - 0.3 – 0.2fT 0.3 + 0.2fT - 0.3 – 0.2fT 0.3 + 0.2fT
QWV CQW (-0.35–0.2fT) flp (0.35+0.2fT) flp (-0.35-0.2fT) flp (0.35+0.2fT) flp
MWH CWH - 0.9 0.9 0.9 - 0.9
MWT CWT - flp-OST flp-OST flp-OST - flp-OST
Longitudinal accelerations asurge CXS 0.1fT - 0.15 0.15 – 0.1fT 0.1fT - 0.15 0.15 – 0.1fT
apitch-x CXP 0.7 – 0.3fT 0.3fT - 0.7 0.7 – 0.3fT 0.3fT - 0.7
gsinϕ CXG 0.2fT - 0.45 0.45 – 0.2fT 0.2fT - 0.45 0.45 – 0.2fT
Transverse accelerations asway CYS 0 0 0 0
aroll-y CYR 0.4fT - 0.25 0.25 - 0.4fT 0.25 - 0.4fT 0.4fT - 0.25
gsinθ CYG 0.1 - 0.2fT 0.2fT - 0.1 0.2fT - 0.1 0.1 - 0.2fT
Vertical accelerations aheave CZH 0.2fT - 0.05 0.05 - 0.2fT 0.2fT - 0.05 0.05 - 0.2fT
aroll-z CZR 0.4fT - 0.25 0.25 - 0.4fT 0.25 - 0.4fT 0.4fT - 0.25
apitch-z CZP 0.7 - 0.3fT 0.3fT - 0.7 0.7 - 0.3fT 0.3fT - 0.7

Load component LCF OSA-1P OSA-2P OSA-1S OSA-2S
Hull girder loads MWV CWV 0.75 - 0.5fT - 0.75 + 0.5fT 0.75 - 0.5fT - 0.75 + 0.5fT
QWV CQW (0.6-0.4fT) flp (-0.6+0.4fT) flp (0.6-0.4fT) flp (-0.6+0.4fT) flp
MWH CWH 0.55 + 0.2fT - 0.55 - 0.2fT - 0.55 - 0.2fT 0.55 + 0.2fT
MWT CWT - flp-OSA flp-OSA flp-OSA -flp-OSA
Longitudinal accelerations asurge CXS 0.1fT - 0.45 0.45 – 0.1fT - 0.45 + 0.1fT 0.45 – 0.1fT
apitch-x CXP 1.0 - 1.0 1.0 - 1.0
gsinϕ CXG - 1.0 1.0 - 1.0 1.0
Transverse accelerations asway CYS - 0.2 – 0.1fT 0.2 + 0.1fT 0.2 + 0.1fT - 0.2 – 0.1fT
aroll-y CYR 0.3 - 0.2fT 0.2fT - 0.3 0.2fT - 0.3 0.3 - 0.2fT
gsinθ CYG 0.1fT - 0.2 0.2 - 0.1fT 0.2 - 0.1fT 0.1fT - 0.2
Vertical accelerations aheave CZH - 0.2fT 0.2fT - 0.2fT 0.2fT
aroll-z CZR 0.3 - 0.2fT 0.2fT - 0.3 0.2fT - 0.3 0.3 - 0.2fT
apitch-z CZP 1.0 - 1.0 1.0 - 1.0
Parent topic: Section 2 Dynamic Load Cases
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