[Paul Riley]

One thing that always got me curious was,why was 3 mins 15 secs used to calculate speed?,why the 3 mins and why the 15 secs? I mean 3 mins is hardly a reliable way to determine a ship's speed.
I much prefer the fixed line method of watching the target and matching speed accordingly,usually for between 15-30mins
I even read somewhere that skilled commanders could estimate speed based on the rate smoke came out of the funnel and the turbulence of the ship's wake,at least to determine whether it was slow,med,fast that is.

Thanks.