ROV Scorpion Deployed By Boat Off Goree Island

You'll find lots of media from this day at Gallery 12.

Eleven of us, including seven ISD students, headed out with both ROVs yesterday morning for our first boat dive.  We rented a boat with Oceanium, an organization offering dive training, dive trips, and operating a well-respected environmental program.  

The kids and I have thus far constructed two ROVs, the frames designed by 6th grade Derek (the SS-Sub), and 9th grade Davy (ROV Scorpion).  They have similar thruster/light/camera configurations:  three 800 gpm bilge pumps, two vertical, one horizontal;  two 20 w halogen bulbs;  a Wisecomm Oc295 video camera, rated to 90 ft, available through amazon.com;  tethered to the surface with three pairs of 18 gauge speaker wire to a 12 volt 7 amph sealed battery;  the camera split to a Sony camcorder and a Toshiba 11 inch DVD player;  all leads waterproofed using a product called PlastiDip.

The two ROVs differ in the length of their tethers:  the SS-Sub has a 10 m tether, the Scorpion was designed with a longer 16 m tether.

It was windy all Friday night, and still gusty on Saturday morning.  Our journey to the lee side of Goree was directly into the wind and the swell.  Progress was slow, and we were sopped with spray, as the boat operator navigated through the waves.  The kids, of course, loved it.  

We anchored in a relative quiet, wind-protected side of Goree in about 10 m of water.  The water was clear, with only a slight current.  The bottom was mixed sand and scattered rock, so the potential for getting snagged was low.  All in all, despite the windy crossing to the island, the conditions were ideal, as the video clips reflect.

The was the first in a series of boat dives.  The intent was, in part, to introduce ourselves to the folks at Oceanium, and to begin to build a longer-term relationship, particularly with the boat operators, who were obviously interested in what we were doing.  

I also wanted to sort out the logistics and give the kids further experience in setting-up the electronics and the console.  The ideal is to dive at night, as around one of the numerous local shipwrecks, but before deploying in the dark, we must be able to successfully deploy the ROV during the day.

Interestingly, for most of the kids attending, working with the ROV is no longer novel.  Most were present to the several pool tests, and several have twice deployed the ROVs at Ile de Madeleine.  For them, it's old hat.

Looking ahead to the winter/spring, I expect to see a marked advancement in ROV design, with the battery being placed on the vehicle (rather than the surface, where voltage loss is a major consideration), with the vehicle's components linked to a series of relays switches, which require a much reduced voltage to engage, allowing us reduce the tetherline (using CAT-5 cable).

The most exciting news is this:  Controlled tests by a member of a Yahoo ROV chat group has shown that bilge motors, of the type we're using, perform to 40 m of depth without the shaft seals failing (water rushing into the motor due to the enormous pressures).  This is huge.  The possibility of dropping a student/teacher-designed ROV to over 30 meters is VERY exciting, and an aim for the new year.  

Stay tuned.