Additional Damage Stability for Pax, Ro-Ro and Ro-Pax Flashcards
1
Q
What it the bulkhead deck?
A
The uppermost deck where top of all transverse vertical watertight bulkheads finish.
2
Q
Outline what is meant by the required subdivision index R
A
- Index R is the minimum standard for subdivision on cargo ships above 80m in length and all pax ships.
- For cargo ships it is based on length
- For pax ships it is based on the number of persons onboard
- Index R must be less than Index A
- The standard comes from SOLAS
3
Q
Outline what is meant by the attained subdivision index A
A
- The probabilistic concept of survival after collision as a measure of the ships safety in a damaged condition
- Based on the probability of occurrence of damage in that area and the probability of the surviving that damage at a range of drafts.
- Surviability is determined by; location of flooding, μ, moments created by flooding, and draft.
- index A must not be less then index R
4
Q
Define the minimum damage stability requirements for pax ships
A
Final condition for vessel in worst condition
- Max list 15° from asymmetrical flooding
- Range of +ve stab not < 16° from θe to θv or θf whichever is lesser.
- Max GZ not < 0.12m allowing for
1. pax movement to one side
2. moment acting on vessel (e.g. wind heeling)
3. Heeling moment of launching fully loaded lifeboat - Waterline lower then area where progressive downflooding can take place
- Cross flooding equalisation shall not exceed 10mins
5
Q
How is attained subdivision index A calculated?
A
- A = Pi x Si
- Pi = probability of that compartment to be flooded
- Si = Survival after flooding of that compartment
- Calculated for three drafts
deepest subdivision drafts
partial subdivision drafts
light service drafts
6
Q
What is the Stockholm Agreement?
A
- Applies for EU-flagged Ro-Pax vessels and Ro-Pax flags operating in EU waters.
- Sets a higher standard of stability for Ro-Pax in damaged condition.
- Small freeboard ≤ 0.3m + Big seas ≥ 4m, depth of water on freeboard deck 0.5m
- Big freeboard ≥ 2m + small seas ≤ 2m, depth of water on freeboard deck 0m
7
Q
Additional damage criteria for Ro-Pax when LLH is flooded
A
- Max GZ not nlt 0.2m
- Range of positive stab nlt 20° from θe to θv or θf whichever is lesser
- θe ngt 15°