Systems and methods for underwater descent rate reduction

A method for underwater descent rate reduction for an underwater delivery vehicle, the method comprising:

• opening a first valve based on a first hydrostatic pressure to permit water to flow into a first chamber of a hydrostatic pressure driven piston assembly;
• developing a pressure differential across a piston head separating the first chamber from a second chamber of the hydrostatic pressure driven piston assembly;
• pushing the piston head into the second chamber to extend a piston rod from the hydrostatic pressure driven piston assembly;
• and
• pivoting a deflecting flap downward into a direction of vehicle descent as the piston rod extends.

An underwater descent rate reduction system, the system comprising:

• at least one flap assembly, the flap assembly including a deflecting flap pivotally coupled to a hinge member, a backing plate pivotally coupled to deflecting flap via the hinge member, and a hydrostatic pressure driven piston assembly having a cylinder member and a piston member;
• wherein the hydrostatic pressure driven piston assembly is coupled between a vehicle housing body and the backing plate and causes the deflecting flap to pivot about the hinge member in a downward direction with respect to the vehicle housing body when the piston member extends from the cylinder member;
• the cylinder member of the hydrostatic pressure driven piston assembly comprising a water chamber and a gas chamber separated by a movable piston head of the piston member;
• and
• the water chamber including a hydrostatic pressure operated check valve that opens to allow water to flow into the water chamber at a predetermine hydrostatic pressure, wherein a pressure differential between the gas chamber and the water chamber moves the piston head to extend the piston member from the cylinder member.