Stability_conditions_(watercraft)

Stability conditions (watercraft) is the term used to describe the various standard loading configurations to which a ship, boat, or offshore platform may be subjected. They are recognized by classing societies such as Lloyd\'s Register, American Bureau of Shipping (ABS) and Det Norske Veritas. Classing societies follow rules and guidelines laid down by SOLAS conventions, the International Maritime Organization and laws of the country under which the vessel is flagged, such as the Code of Federal Regulations.

Stability is normally broken into two distinct types: Intact and Damaged

Intact Stability

The vessel is in normal operational configuration. The hull is not breached in any compartment. The vessel will be expected to meet various stability criteria such as GMt, area under the GZ curve, range of stability, trim, etc.

Intact Conditions

• Lightship : The vessel is complete and ready for service in every respect, including permanent ballast. All normally flooded spaces such as sea chests are considered but the vessel has no cargo, crew, provisions, ammunition or any other load item.

• Light Operating or Light Displacement : Along with all the Lightship loads, the vessel has all systems charged meaning that all fresh water, cooling, lubricating, hydraulic and fuel service header tanks, piping and equipment systems are filled with their normal operating fluids. Crew and effects are at their normal values. Consumables (provisions, potable water and fuel) are at 10% full load. Ammunition and/or cargo is not included (0% of full load).

• Full Load Departure or Full Displacement : Along with all the Lightship loads, the vessel has all systems charged meaning that all fresh water, cooling, lubricating, hydraulic and fuel service header tanks, piping and equipment systems are filled with their normal operating fluids. Crew and effects are at their normal values. Consumables (provisions, potable water and fuel) are at 100% capacity. Ammunition and/or cargo is at maximum capacity. The vessel is at its limiting draft or legal load line.

• Standard Condition (Only for military vessels) : Along with all the Lightship loads, the vessel has all systems charged meaning that all fresh water, cooling, lubricating, hydraulic and fuel service header tanks, piping and equipment systems are filled with their normal operating fluids. Crew and effects are at their normal values. Consumables (provisions, potable water and fuel) are at 50% capacity. Ammunition and/or cargo is at 100% capacity. This condition is normally used for range and speed calculations.

• Light Arrival : Along with all the Lightship loads, the vessel has all systems charged meaning that all fresh water, cooling, lubricating, hydraulic and fuel service header tanks, piping and equipment systems are filled with their normal operating fluids. Crew and effects are at their normal values. Consumables (provisions, potable water and fuel) are at 10% full load. Ammunition and/or cargo is at 100% capacity.

Damaged Stability

• Damaged : The vessel in the assessed "Worst Intact Condition" is analytically damaged by opening various combinations of watertight compartments to the sea. The number of compartments and their location are dictated by IMO regulations, SOLAS conventions, or other applicable rules. Typically these conditions are identified by the compartment(s) damaged ex: "Hold #3 and Water Ballast Tank 4 Port"

See also

• Naval architecture
• Hull (watercraft)
• SNAME
• Instantaneous stability

References

External links

• nvr.navy.mil, definitions

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