Speed Log

Question 1

what are the different types of Speed Logs?

Answer 1

 Impellor (Spinning device).
 Pilot tube (Device using the difference in pressure to measure speed).
 Electromagnetic (Sea water passes through and creates a small charge which is then measured to calculate the ships speed).
 Doppler (Uses sound wave reflection from the seabed).

Question 2

How should the Speed Log be maintained?

Answer 2

 Should be calibrated regularly (Miles).
 Should be maintained as per the ship’s planned maintenance system.

Question 4

What errors are associated with the Speed Log.

Answer 4

 All due to calibration.
 Doppler log gives speed over ground in shallow waters.