Posted by Dimitris on .
What is the necessary rate of turn ,for a vessel that moves with a speed of 25 miles per hour to complete a 90 degrees turn ,starting the turn 1 mile prior of the way point of altering course?
 Navigation  SraJMcGin,

Navigation 
Damon,
Radius of turn = 1 mile
How long is the ship turning to turn 1/4 of a circle?
circumference = 2 pi r = 2 pi miles
so the ship travels pi/2 miles while turning.
speed = 25 mph assume constant
time = distance / rate = (pi/2)/25 = pi/50 hours
so the ship turns 90 degrees in pi/50 hours 1432 degrees/hour
times 1 hour/60 minute = 24 degrees/minute
times 1 minute/60 seconds = 0.4 degrees/second