Why is this Dive Platform Moving?

For more than four decades, WHOI’s deep-sea submersible Alvin has transported scientists through ocean depths of 2.8 miles. Now a new sub is being built to continue that legacy and bring people even deeper (up to four miles). Alvin and the support team work from the WHOI-operated research vessel Atlantis, equipped for moving the 17 metric ton (35,200 pound) submersible into and out of the water. Trained divers (members of Alvin’s team) assist with the sub’s launch and recovery.

(Woods Hole Oceanographic Institution)