Israel’s KikFin has produced a jetpack with fins that straps onto a swimmer’s back and propels them though the water. It can change direction with the slightest movement of the head. The hands-free operation is ideal for professional divers and rescue services. It also attaches to surfboards.
https://nocamels.com/2023/08/hands-free-underwater-jetpack-gives-divers-and-surfers-a-boost/