1. CALCULATING TIME, SPEED & DISTANCE 2011

2. Time / Distance / Speed Calculations

3. All these calculations revolve around the following formula 60D = T S

4. Time / Distance / Speed Calculations T = time in minutes S = speed in knots D = distance in nautical miles 60D = T S

5. Calculating an ETA

6. Measure the distance along the course line to the destination in nautical miles

7. Calculating an ETA

8. The distance from Ladysmith (top left hand corner) to off Norway Island is 12.9 nautical miles. Using 60D = T S 60 x 12.9 = T in minutes = 25.8 minutes 30

9. Calculating an ETA Add this time to the the departure time, e.g. 0800 LT, and your ETA off Norway Island will be around 0825 LT.

10. 6 Minute Finger Method

11. This method may be used with either dividers or fingers held a set distance apart for a rapid estimation of distance.

12. 6 Minute Finger Method At 30 knots the vessel will travel 3 nautical miles every 6 minutes. Set dividers to 3 nautical miles on the latitude scale, and then run them down the course line counting off 6 minutes as you go.

13. 6 Minute Finger Method

14. Alternatively put two fingers over the 3 nautical miles on the latitude scale, and then run them down the course line counting off 6 minutes as you go. This will give you somewhere around 24 minutes plus for a time travelled.