Five hours.....
Proves that you can stay focused, and make a safe landing when tired, normally at your home site. At least that's the story I got. Makes some sense, or at least it did in the past where low performance gliders landed out rather more often than we now seem to, and a 300km triangle could last six or seven hours.
I don't think mine proved anything more than inbuilt stubborness, as I did it on a ridge in an elderly glider with an open cockpit in a howling gale. Low cloud base, rain showers, didn't really enjoy it at the time. Ended up flying over six hours waiting for the wind to drop enough to make a safe circuit. Still, it doubled my solo time on gliders for the price of one bungy launch.
Mary, I'm a Falke flyer some of the time. Makes sense in a small club midweek. I turn the engine off as soon as we are going up halfway decently, because to get an old small engine Falke to go up at any decent rate off climb needs a thermal, which is prolly better than the engine anyway.