I can only guess it's another stolen OB case

Appears to me to be a observation bell that's lowered from a surface ship. I'm gonna say it's someone's way of repairing the dock (the remote manipulator arms are out back, unseen in this photo) in the cold spring Winni waters. I'm not saying it's Grant's or Senter Cove Guy's but I'm pretty sure it's not WinniDiver's. Once dock repair season is concluded it's used as a ride at Weirs Beach. For $12/ticket ($8.52 for kids under 14) you get towed underwater behind the WinniWaterTaxi for a once-around Gov's Island where you can see firsthand the many natural wonders the lake has to offer. Yes there are rocks, water, blind fish (you can tell by the way the swim around and bump into the rocks), Fountains (dare I call them water Fountains

) and more fish that are, well let's say this nicely for the kids, "resting peacefully" (you can tell by the belly-up position and lack of any apparent movement). Yup a sure fire hit for the kids of all ages, I'm surprised y'all never seen this before

Better buy your tickets now before the
Executive Committee hears about the fun and starts an investigation !
ps - Those "sleeping" fish are actually imported from Norway (surely you've heard of bluefish, Norwegian Blue fish ?!?) every season and they're just "pining for the fjords" come summer-time.
pps - Any one interested in the Gov. I bridge, well contact me, I have quite a deal for you !!! But
sssshh, let's just keep this between you and me, OK ?