TIP FOR CALCULATING THE SPEED OF A SHIP WITHOUT HAVING TO STOP THE MACHINES: Hi all captains, to know the speed of a ship, I advise you to use the method performed in this video. Indeed, the latter allows you to get closer to the ship, without stopping the machines.
see at 13min40 in this video, noticing that I am far from the target, I put the machines back at full speed to get closer and thus perform my second bearing of a more favorable position
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PROTOCOL: take two points of the vessel's heading at minimum intervals of two minutes. Draw a line between these two points and measure it. This will give you the distance the ship has traveled in two minutes (see at 8 mins & 22 mins in this video).
ps: but the ideal is 3 to 4 minutes like in this video. Indeed, this allows you to have an estimate of the speed of the ship much closer to reality, because a boat always accelerates and decelerates. And yes, they are big fat whales ,)
All you have to do is use this formula to calculate the exact speed of the target ship.
Speed = Distance / Time
Example from this video:
Time interval between the two points: 4 mins
Distance between the two points: 1460 m
V = 1460 / 4 = 365 m/min
To convert from m/mins to knots multiply the number by 0.0324
365 x 0.0324 = 11.83 = 12 knots
All you have to do is put this data in the right "SPEED" dial. Nevertheless, I advise you to put one knot less so 11, because the boat always slows down when it sees torpedoes coming.
Cordially. Captain_PUJOL
