What you know about controlled radial turn ? roti %u2013 ship requirements , roti %u2013 formula:-

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All ships of 50,000GT and above shall have rate of turn indicator..

Advantages
1. Precise movement of the vessel
2. Lesser loss of speed & drift angle.
3. can steady the ship on the next course with minimal rudder movements

Rate of turn (Degrees/ minute) = 0.96 x (V/ R)
where V= Ship’s speed over ground, in knots and,R= Radius of the turn in nautical miles.

The distance of wheel over point from the point where the turn is to become effective is usually taken as one ship’s length but it is recommended to find it out by some practice turns on the type of ship one is serving .
Following formula can be used to find the distance of wheel over line from the new course line and the same can be used to set the parallel indexing line or the line of turn for giving the wheel over order:
Distance of wheel over line from the new course line
  = F sinθ + R (1 – cos θ )

where,F = one ship’s length (usually), R = Radius of the turn,θ = Change of course in degrees between initial course and final course