This is an "ice carousel"

YouTube link

It goes round-and-round, powered by about a half dozen good-sized outboard motors.

Sort of related: Round ice.

Addendum:  More on Minnesota ice carousels.

And more:

The latest battle in a cold war waged in Minnesota, Maine, Finland and Estonia was fought this week in Little Falls, Minn.

At stake: bragging rights for who can create the world’s biggest ice carousel... now extreme ice carousel builders across the world are one-upping one another in a challenge to create the biggest and best.

The latest attempt: An ice carousel in Little Falls that is about 500 feet in diameter, as wide as the Foshay Tower is tall, is spinning away on Green Prairie Fish Lake... There will also be four 40-foot carousels spinning within the larger carousel.

Short video at the link.