We had the proa broad reaching off Cape Schanck in late August. Winds were 17 to 20kts at the time. The linked video shows the track and speed:
https://www.youtube.com/watch?v=1fsxnaYi-PM

The boat was shunted once clear of the rip at Port Phillip then course was South East, broad reaching at about 110 to 120 degrees to the true wind. We were in irons for a short period once turning east before the dagger board was lowered. The fetch reduced as we approached Cape Schanck with waves below 1m when in the lee of the Cape. That is when I took the video as we were seeing the highest speeds to date at that point. Best speed was achieved toward the end of the reach when the well was not ploughing waves.

The well is only 600 off the water so any waves above 1m start to impact this long low section and drag increases.