This is how paragliders and hanggliders do it all the times.
They call them Gates, and they can have several of them in a sequence.

LK8000 is dealing with start gates, providing to the pilot the countdown,
the estimated time to get to the start line (or exit the start cylinder),
and suggesting when it is time to go, considering the desired MC set.
It will bring the pilot crossing the start gate 1 second after the gate is
open.
This is fundamental, because the parking thermal may be some miles away from
the start gate, and nevertheless be the good point to wait for the open.

It is a Grand Prix start, at all effects, but with several gates available.
Paragliding people know how to get fun !

paolo


wrote in message
...

On Thursday, November 15, 2012 5:15:05 PM UTC-5, Simon Taylor wrote:
As I understand it, a 'regatta start' is where the start line opens at a
specific time and pilots are effectively penalised for starting before or
after this instant. If this interpretation is right, what methods are used
by pilots to estimate their arrival time, and what maneuvers are used to
delay arrival?

You need to start after the task opens. Orbiting close to the line, assuming
lift reasonably close, should make it not too hard. Since a circle only
takes about 20 seconds, timing isn't so hard.
What is hard is starting so you line up the lift on course.
These aren't big, hard to turn sailboats.
FWIW
UH