Quote:
|
it gave me a reading of about 7 knots when the ship was clearly moving at 3-4 kts. or slower
|
You probably used the 150 metres scale for a ship that was exactly half that length. Dividing the resulting speed by 2 you would have the proper result (3.5 knots).
Using the chrono doesn't require anything else than start/stop and read the result. But you must pay attention that you are using the proper scale, and if the ship you measured isn't the same length as one of teh scales (F.e. small merchants are 78 metres, which doesn't match with any of the three scales 100/150/200) you must choose the scale that has the easiest division and also divide the result.
In that example: 78x2=156 metres so you use the 150 metres scale but divide the resulting speed by 2
I would have liked to put a fourth scale for small ships (75 metres), but there was simply no more space available, and the division by 2 of the 150 metres scale is easy enough for everyone.
Take a look at Joe's Youtube video,second part in the other thread, makes all very easy to understand.
Good hunting