Here is a bit more on some of the engineering solutions manufacturers have delivered:

Hakai: What is a particularly clever engineering solution you’ve used on other megayachts?

AI: We have delivered a yacht with a raising pool bottom. After emptying the pool, the bottom can be raised until it is flush with the surrounding deck. Then it can be used as a dance floor or even as a landing area for a helicopter.

Recently, we have presented project Skyback, developed in collaboration with the Dutch designer Cor D. Rover. Skyback is a yacht with a glass covering that can slide out from the superstructure and cover the external deck area. This lets the owner enjoy the external pool even when sailing in the Arctic.

Yachts can also have helicopter hangars or flight decks and floodable docks to access the ship with a tender. They have the most modern propulsion plants. They feature the lowest possible noise and vibration levels—so low that while sailing at full speed you often don’t have the feeling of being on a ship.

This is pretty insane and the talk of floating cities and these yachts may be looking very similar as things progress.

thanks to hakai magazine for the info