Why is my boat faster on a stbd tack?

[Pumbaa]

[QUOTE=gjorgensen;2443694]Make sure you're comparing SOG on each tack vs. speed from a transducer. The paddlewheel transducer being off center can often read differently on different tacks.

This is the reason, a boat changes it's underwater hydrodynamic shape when it is healed. So on one tack a paddlewheel will be closer to the surface and on the other tack buried deep underwater. One side will be accelerating the water around faster than the other, I believe it is the water near the surface that is travelling faster. So if your sensor is on the starboard side it may read faster on starboard tack because it is closer to the surface and the faster flow of water trying to keep up with leeway and surface deviation due to the passage of the hull through the water. Water doesn't stretch but the surface can. Unless your paddlewheels in the middle in which case it 's probably just not in straight.