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Rolling Period Formula



If your vessel has a GM of one foot and a breadth of 50 feet, what will be your full rolling period?

Given:
            GM = 1 ft
      Breadth = 50 ft

What is asked:
           
Rolling period

Solution:

            The necessary thing to remember in solving for the rolling period is to note the unit of the ship’s breadth. This is so because our formula in getting the rolling period depends on it. Supposing, if the unit of breadth is feet, we have to multiply the breadth by 0.44. On the other hand, if the unit of breadth is meter, we have to multiply the breadth by 0.797.

            Now since the unit of breadth in the problem is feet, the rolling period formula therefore would be 0.44 times breadth over the square root of GM.

Rolling Period = (0.44 x Breadth) ÷ √GM
                     = (0.44 x 50 ft) ÷ √1
                     = 22 ÷ 1
                     = 22 seconds