Abstract

The Howe Sound is home to a rare marine animal, the glass (hexactinellid) sponge. Our client had an underwater Remotely Operated Vehicle (ROV), and requested that we design and build an add-on Sample Retrieval System (SRS) that could be used to retrieve small samples of sponge from depths as great as 1000 feet below sea level.

We produced a prototype SRS that can retrieve two samples per dive. The linear actuator (top) opens and closes the gripper, which shears a small segment of sponge as it closes. The sponge is retained inside the gripper, which is held shut by a torsional spring.

The grippers are mounted on a carousel. Once a gripper has been used, the carousel motor (bottom) turns the carousel until the un-used gripper engages with the linear actuator and is ready to use. This carousel is easy to swap out, for example to increase the number of grippers, and therefore the number of samples retrieved in one dive.

Finally, the shoulder motor (right) is used to pitch the entire SRS to adjust to the geometry of a given target sponge, as well as to stow the SRS vertically against the ROV.