What?! I don't agree.
The description of VMG that Velocitek provides is no different than what Hobiegary described. Velocitek simply chose to only illustrate the optimal situation that Hobiegary described:
velocitek writes:
The device then uses
trigonometry to extract the component of your actual speed that is aligned with the upwind-downwind
line defined by TWO reference locations you stored in the device's memory.
This means VMG is calculated in a correct manner, and for example, will not be close to 0 or negative when you are close to the layline but on the other tack than the one that is laying the buoy directly (say short before tacking)
When a gps calculates VMG as velocity of approach to ONE certain point, VMG will be close to zero in the situation described above. This is a very important difference to sailors. Simple trigonometry.
