The reason? She was on a 30+ year old "round bottom" longboard, the Magnum 390. She was fast the entire time, even in the lulls, with a 6.5 m sail. She also snapped the board around on a dime when it was time to turn, and I don't think she crashed at all. We started at Kalmus in offshore wind, and sailed across the shipping channel where the wind was a bit steadier. When I dragged my WindSUP across the sandbar to see if the water in the "baby bay" at Egg Island was flatter (it was not), Nina sailed around and met me a few minutes later.
Why was it so much fun? I can only guess. I think a big reason is the excellent glide of the Magnum, which either is a D2 board, or at least quite similar (the back end is a bit flatter, and the nose is not quite as pointy, as other D2 boards). The board reaches about 8 knots speed in maybe 5-6 knots of wind, which feels almost as fast as planing on a shortboard. Another part of the fun may have been that the board is not that easy to sail, so it may have required a bit of concentration .. can you say "zone"? I also had fun working a bit on my back-to-back in gusty conditions, but the girl sure had more fun.
Things evened out a bit the next day, where I had a fantastic session in 10-20 mph wind on my F2 Lightning in Barnstable Harbor, while Nina stayed home. It was a beautiful day, and planing near the dunes on the far side, with miles and miles of water just for me, was just about perfect. I did not even mind the little swim when the mast foot came loose and the board started to drift away. Perhaps my conversion to a standard single-bold mastfoot needs a bit of a refinement...