Me & Dirk (Dilldapp) dove Maceday lake from my boat this afternoon. We hit 100 ft before turning around and it continued getting deeper past there. The water was 40'F down there, but it was much much warmer at the surface (I think it was in the 60's but not sure). I think we hit 2 thermoclines on the way down - the bottom one was at 87 feet and the visibility wasn't as good below it. The vis was pretty great above the 87 ft thermo, much better than the other inland lakes I've seen. The shallower thermocline wasn't as well defined as the deeper one. Then we found the bowrider at 77 ft & the rowboat at ~16 ft on the ascent, with lines on them. There's an interesting apparatus down there, too.
There was another group of divers leaving just as we arrived by boat, that had parked in the 'no parking' zone and walked down the hill. That is also one big steep trail to enter/exit the water from there. Parking at the boat launch is no picnic, either. That parking lot is very small, and we took the last 2 spaces. If we had gotten there any later, we would have been S.O.L. But then it was a short and easy boat ride to the dive spot, and the shoreline is made up of sand and pea gravel, so we were able to beach the boat there without the need to anchor offshore.
Ted, this would be the ideal place to try diving off your jetskis. It's a short ride from the launch and it avoids the problems that come with parking up on the hill.
-Ray