Motion compensating ship personnel transfer gangway - GIF

[Toolmaker51]

I agree with 12bolts. The Hoppe device has two baffles on the stable side retaining fluid opposite lowered side of 'hull' simulator.The fluid is an active counterweight. Not sure how that will be practical in a full size displacement hull. The pair of baffles would need a function to set a particular level for sea conditions at that time.

Don't visit Hoppe's site. This page indicates they have more than a little gray matter at hand....https://www.hoppe-marine.com/?q=en/node/17