CV e wrote:

Assuming you want to use the thermals to supplement
your engine, as you said, you will be climbing under
power, **at a higher climb rate than the gliders**

I wouldn't be so sure about that. :-)

and coming at them from below, where it is
more difficult for them to spot you.

Definitely more difficult if you're below, not to mention understandably
extremely unnerving to be able to hear a powered aircraft below and not be able
to see it.

So if you plan to use thermals, make sure you are
aware of where the gliding sites are, in what areas
gliders are likely to be flying, and remember to keep
a good lookout, even more than usual.

Thank you! I'd like to add...even if you are NOT planning to use thermals, if
you just happen to be flying through or past a glider site, please take the
time to look at the AFD or Flight Guide for specifics such as the location of
aerobatic boxes that may be in use while you're passing through (bad idea) and
any other info on the preferred path for powered aircraft during hours of
glider operation.

It would also be good to find out what frequencies
are used by the gliders, listen in and let them know
where you are.

Never hurts, but not all gliders even have radios, so don't assume that because
you've called, they know you're there. Again, no substitute for (a) having
researched how and where they operate and where they'd like you (in a powered
aircraft) to fly during their hours of operation, and (b) using common sense
about flying through an area in use by another type of aircraft.

While the original poster mentioned gliders, I may be wrong, but I don't think
he was talking about using the SAME thermals simultaneously with gliders.

--Shirley
Glider Pilot