The Wave and Swell Information dialog allows for the input of Sea Wave Information: "Period of Sea Waves" (code PwPw), "Period of Swell Waves" Primary (code Pw1Pw1) and Secondary (code Pw2Pw2). "Height of Sea Waves" (code HwHw), "Height Swell Waves" Primary (code Hw1Hw1) and Secondary (code Hw2Hw2). "True Direction from which Swells are Coming", Primary (code dw1dw1) and Secondary (code dw2dw2).
Period of Waves and Swells -
Definition: Wave (swell) period is the time between the passage of two successive wave (swell) crests past a fixed point.Height of Waves and Swells -
Method of Measurement: Count seconds, preferably with a watch. Note a small object such as a piece of wood, foam or bird floating on the water. Watch the amount of time it takes for the object to move from crest to crest.
Dialog Operation: Input the wave and swell period into the edit boxes as labeled. The codes PwPw, Pw1Pw1, and Pw2Pw2 are automatically coded with the input value.
Definition: Vertical distance between trough and crest for wind waves and swells in units of meters or feet. The primary swells are higher than secondary wavesTrue Direction from which Swells are coming -
Method of Measurement: Visual estimate. It is best for observer to locate on side of ship from which the waves are coming.
Dialog Operation: Input the height of wave and swells into the edit boxes as labeled. Use feet or meters, the correct units are shown at the top of the edit boxes (unit selection is made at the Initial dialog). The codes HwHw, Hw1Hw1, and Hw2Hw2 are automatically coded in half meters.
Definition: True direction in degrees from which primary and secondary swell waves are coming. Use swell wave height to distinguish primary from secondary swells. Swells are waves that have traveled into your area of observation after being generated by wind in other areas.
Method of Measurement: Visual estimate. Sight along the swell wave crests. The direction the swell waves are coming from will be 90 degrees to the crestline.
Dialog Operation: Determine if the Swell is direction is variable or not and select the appropriate radio button. If the direction of the swell is variable then the code value of 99 is given automatically. If a direction is determined then put that value in the edit box. The code is automatically determined in tens of degrees.