Stability Problems Associated with Ro-Ro and Ro-Pax

Question 1

List stability issues with Ro-Ro and Ro-Pax Vessels

Answer 1

• Lack of subdivision of vehicle decks
• High permeability of vehicle decks
• Bow and and stern doors
• Potential for cargo shift of vehicles
• Wind heeling
• Large angle of heel when turning
• Flooding of vehicle deck during fire fighting
• Estimation of vehicle weights
• Potential for large loss of I.WPA
• Pax and crew evac

Question 2

Issues with lack of subdivision of vehicle decks

Answer 2

• vulnerable to stability loss, FSE and listing, potential for large loss of I.WPA

Question 3

Issues with High permeability of vehicle decks

Answer 3

• Greater potential for flooding

Question 4

Issues with Bow and and stern doors

Answer 4

• Must maintain watertightness
• Subject to considerable wave impact due to high speeds and large bow flare
• Quartering seas can cause excessive loads on locking pins, increased with heel
• Flat stern ram or slewing ram can cause serve slamming

Question 5

Issues with Potential for cargo shift of vehicles

Answer 5

• Wide range of vehicle types all with different securing methods
• If cargo were to break loose then could cause damage in addition to list
• Hazards from spilled cargo too

Question 6

Issues with Wind heeling

Answer 6

• Considerable height above water line ∴ large exposed lateral area can cause wind heeling

Question 7

Issues with Large angle of heel when turning

Answer 7

• Sharp turns at high speeds may be required when running in congested waters, leading to large heeling angle

Question 8

Issues with Flooding of vehicle deck during fire fighting

Answer 8

• Petrol tanks for vehicles are a hazard
• Water on deck pose FSE hazard if scuppers are blocked

Question 9

Issue with Estimation of vehicle weights

Answer 9

• Estimations of vehicle weights could lead to misleading data. Allowance of 7% for estimations

Question 10

Issue with Potential for large loss of I.WPA

Answer 10

• When the bulkhead decks becomes flooded (vehicle deck) then you would have large loss of I.WPA ∴ large reduction in BM ∴ reduction in KM which ∴ could lead to unacceptable GM ∴ a rapid capsize

Question 11

Issues with Pax and crew evac

Answer 11

• rapid sinking of vessel can be hazardous for large evac operations

Question 12

Methods of improve Ro-Ro Ship Stability

Answer 12

• Perforated vehicle decks that allow the automatic down-flooding of water
• increase subdivision of vehicle deck
• have inner bow door to limit water ingress
• increase planned maintenance of Bow and stern doors
• Fit sponsons to increase WPA