After the sextant of the future (¹), presented at the Paris Boat Show last December, here is the loch of the future revisited by a "Professor Calculus", an electronics engineer and genius inventor from Nantes.
The oldest among us will certainly remember this venerable and inexpensive instrument of the old sailing navy : The "boat loch". Quote (²):
The "boat" is a wooden plank, weighted to float vertically and connected to the log line by a crow's foot. On the line we tie knots, spaced in principle 7m72 (or 1/240th of a nautical mile). We put the "boat" in the water and let the line go. we then count, from the first node, how many knots pass through the hand in 15 seconds, which gives the speed in knots.