Before I did my little triangle task, I had a nice flight that I
cut short when after thermaling up to cloud base I noticed that I hadn't zipped
up the sprog pockets. Two of my sprogs were swinging outside the undersurface of
the sail when I noticed them at 4,500'.

I had interrupted my setup and left the pockets unzipped and didn't notice it with
my cursory pre-flight. When I came off the cart I noticed that the bar pressure
was a bit light so I backed off on the VG, which I normally set to 1/2 when
towing. It is not unusual for me to notice light bar pressure on tow and to
readjust the VG, so I didn't think much of it.

After I got off tow I noticed that the glider was really easy to handle, but it
felt basically normal. I was in a 2 m/s thermal so I just thermaled up to cloud
base. At the top of the thermal I pulled on the VG and looked around. Then I
noticed the open under surface and the sprogs hanging lose.

I flew to an area of sink, put the glider into a turn, and unthermaled until I
was low enough to land. The landing was uneventful. So, it seems to me that even
if you don't have your sprog zippers zipped up, the Wills Wing T2C 144 flies
just fine. I have also flown it with the main zipper unzipped and didn't notice
any difference.