The RAM-Boat 8 mechanical design is loosely based upon successful ROV designs that employ thrusters in place of control surfaces.  It has 2 horizontal thrusters for forward and yaw motion, and two “vertran” (vertical-translation) thrusters for vertical and sway motion.  Electronics are housed in a thick 300m depth acrylic tube and mounted with other hardware on an aluminum “80/20” open frame. The open frame allows the thrusters to be aligned with the center of mass to avoid roll and pitch.  The frame supports a cast acrylic pressure tube 28” long by 6” diameter by 3/8” thick.  Collapse depth for this tube is calculated to be 1000 ft.  The tube is fitted with PVC end-caps.  One end-cap contains 6 SubConn underwater connectors and the other is fitted with an acrylic dome that can house two robot cameras, one looking forward and one looking down.  

The frame has a very stable “A” frame shape acting as its own stand, and placing the center of mass in the open space at the center of the frame.  Four SeaBotix DC brushed thrusters are mounted on the frame on sliding mounts that easily allow alignment of the thrusters with the center of mass to eliminate roll and pitch movements.  The 2 horizontal thrusters provide forward and turning movements via a single RC dual motor controller with mixing capability that takes separate servo pulse inputs for forward speed and yaw rate.  The 2 “vertran” thrusters are similarly connected, with separate inputs for vertical and lateral (sway) rates. 

RAM-Boat 8 uses a solenoid-released marker design based on a common dart. Darts show a very stable underwater trajectory when released with predictable results. The marker solenoid assembly is mounted at the bow of the vehicle in order to place it nearly in line with the down looking camera tasked with targeting the bins.   The markers are independently released after a command from the NetBurner 5213 leg controller actuates a relay that discharges a capacitor to each solenoid.