Stresses

Question 1

Hogging

Answer 1

• When middle of ship is supported

Question 2

Sagging

Answer 2

• When ENDS of vessel are SUPPORTED

Question 3

Dynamic loading ( longitudinal stresses)

Answer 3

• longitudinal stresses caused by waves and movement in a seaway
• Maximised when wave length is equal to ship length

Question 4

Vibration

Answer 4

Vibration areas will cause metal fatigue and cracks

Question 5

Discontinuity

Answer 5

• Discontinuity need extra stiffening (Doors, hatches, openings)
• reason most rounded

Tensile stresses

Question 6

Pounding (local stresses)

Answer 6

• Stress caused by bowel clearing the water and crashing down, causes upward pressure.
• Restricted by adding bottom stiffening and bow an additional side girnders

Question 7

Painting (local stresses)

Answer 7

• In and out pressure on the bowel due to waves
• Reduced by fitting : panting beams, stringers and reducing frame spacing

Question 8

Static loading (transverse stresses)

Answer 8

• water pressure causing inward pressure on Hull plating
• dry Dock causes outward stressing

Question 9

Static loading (longitudinal stresses)

Answer 9

— Existent stresses at rest

Question 10

Shearing stress (longitudinal stresses)

Answer 10

• The effect of different levels of buoyancy and load on different sections of the ship

Question 11

Dynamic loading (transverse stress)

Answer 11

• Side pressure due to ships rolling crates ‘racking stress’
• overcome with bulkhead, tank side brackets and beam knees