6.7 Stability and WT Integrity - 6.7 Stability and WT Integrity Flashcards
Stability Reference Points
Picture
Center of Buoyancy
Follows the waterline
picture
Center of Gravity
Point at which all weights could be concentrated
COG moves towards a weight addition
COG moves away from a weight removal
Righting Arm
Distance between the forces of buoyancy and gravity
When is stability always reduced?
Gravity is high
Gravity is off centerline
Danger Angle
One-half the angle of heel corresponding to the maximum righting arm value
Free Surface Effect
Occurs when a compartment or tank is only partially flooded/filled
When the ship rocks due to the gravity of the liquid shifting constantly
Free Communication Effect
Compartments must…
be open to the sea
be partially flooded
be off centerline
X-RAY/ YOKE /ZEBRA Fittings
Special permission required, must be logged in the DC Closure Log if opened during the corresponding Condition of Readiness
CIRCLE X-RAY / CIRCLE YOKE / CIRCLE ZEBRA Fittings
May be opened with out special permission to transit, inspect, and access vital spaces
Dog ZEBRA Fittings
Set for Darken ship
WILLIAM Fittings
Vital sea suctions, ventilation, and maintenance fittings for mobility
CIRCLE WILLIAM Fittings
Access and ventilation fittings
X-RAY Condition of Readiness
In homeport, in fair weather, normal working hours
YOKE Condition of Readiness
At sea / inport during peacetime, outside of normal working hours
MODIFIED YOKE Condition of Readiness
Fittings below the waterline are closed, above the waterline may be left open to improve accessibility and habitability
ZEBRA Condition of Readiness
Set during General Quarters, entering and leaving during wartime, when in danger
MODIFIED ZEBRA Condition of Readiness
CO may wish to set a modified material condition ZEBRA to provide higher survivability stance than condition YOKE but less restrictive than ZEBRA
CIRCLE WILLIAM Condition of Readiness
Set to prevent contamination in a CBR environment
Metacentric Height (GM)
Distance between the COG and the meta center.
Prime determiner for stability
Large GM = Fast roll period
Small GM = Slow roll period
Righting Arm
The distance between the forces of buoyancy and gravity
Perpendicular line drawn from the COG to the point of intersection on the force of buoyancy line
How to we utilize Compartmentalization on ships?
- Decks
- Platforms
- Levels
- Bulkheads
