Stability Flashcards
What is an angle of Loll?
Caused by External Forces and a Negative GM.
What causes a negative GM?
May occur due to too much weight on deck and not enough weights low down.
Consumption of Fuel not Calculated correctly. (Commencing Voyage with Small GM)
Ice Accretion. (increasing weight on Deck)
All vessels should proceed to sea with a positive GM as per the intact Stability Requirements.
How do you solve a Angle of LOLL
Pull G back under M.
Ballast weights low down first.
(DO NOT Ballast High side first)
What is the concern with an Angle of Loll?
The vessel may capsize.
What would be your concerns if jettisoning Cargo to Solve Angle of LOLL?
Jettisoning Timber Deck Cargo would be hazardous to the person carrying out the task.
A danger message should be broadcast as per SOLAS.
To all ships in the area.
To the nearest coast station.
What causes Parametric rolling? What vessels does it occur on? What type of Seas?
1 period of roll for every two wave crests.
Occurs on fine line vessels.
Short low Swell on the Quarter or Fine on the Bow.
What is Synchronised Rolling? And what causes it?
The Period of Roll is equal to the period of the swell.
Fine line vessels, with Beam on Swell.
How do you solve Parametric Roll?
And how do you solve Synchronised Roll?
Parametric Roll - Initial action alter course and speed.
Synchronised roll- Initial action alter course only (Speed has no effect)
Once stable rearrange weights. - Re arrange ballast and press up tanks to reduce free surface.
What is angle of List?
Caused by internal weights. The vessel will move around G, when G is off the centre line.
What Vessels are liable to Angle of Loll?
Vessels with a low initial GM. Such a Vessels carrying timber secured in accordance with the Timber Deck Cargo Code - Initial GM of these is 0.10m
What is Dynamic Draft?
This is the ships draft when making way, subject to SQUAT, SEA, SWELL and HEEL When turning.
