Contents
What causes ice accretion?
Ice accretion at sea involves the build-up of frozen sea water on ships. Other factors that affect ice accretion are the speed and direction of the ship (in relation to the wind and sea), wave height, sea surface temperature and water salinity.
How is ice accretion measured?
Ice Accretion occurs when rain or drizzle falls with surface temperatures at or below freezing. measure the thickness of ice in tenths of an inch. You can also measure Ice Accretion on a flat surface. If there is only a small amount of Ice Accretion which is less than a tenth of an inch report it as Trace (T).
What will happen to the vessel center of gravity when there is ice accretion on deck?
The accumulation of ice on the deck, the deck housing tops and other places of the ship raise the CG of the vessel owing to the growing weight and location of loading. The rise in CG raises the KG of the vessel and as we will see in the diagrams, this affects the dynamic stability of the vessel.
What is the definition of severe ice accretion?
Essentially it states ice accretion is severe if it exceeds 5 mm in depth. There’s no time dimension associated with the definition to clarify a rate of accretion. It’s just a linear depth measurement.
What is an ice phobic ice fearing coatings?
“Ice-phobic” (ice fearing) coatings can be applied to repel water and prevent ice build-up. Ice that does form over the coatings will be easier to remove. U.S. Navy (1988) recommends two ice-phobic coatings for prevention of sea spray icing on vessels: Flourocarbon penetrating coating (FPC).
How bad is a quarter inch of ice?
When a quarter-inch or more of ice builds up, severe impacts can result. Ice can increase the weight of tree branches up to 30 times and can add 500 pounds of extra weight to power lines. Consequently, tree branches, power lines and power poles can fall.
Can radar be useful in detecting ice?
A radar can be useful in detecting ice, but the returning signal which bounces off ice (even icebergs) is very faint, much lower than from ships. Conventional marine radars are designed for target detection and avoidance. An X-band radar set to a short pulse can give improved results.
What is the difference between rime and clear ice?
Rime ice is lighter in weight than clear ice and its weight is of little significance. However, its irregular shape and rough surface make it very effective in decreasing aerodynamic efficiency of airfoils, thus reducing lift and increasing drag. Rime ice is brittle and more easily removed than clear ice.
Is 0.2 inches of ice a lot?
With widespread ice accumulations of over 1/2 inch, there is severe tree damage and power outages may last for days.