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Currently, Bob is limited by its instrument housing acrylic dome to 750 meters, but earlier versions can go to 1,500 meters, or about a mile deep. I have hardware for full ocean depth - 11 km, the Mariana trench, but it is not in use. Most of the area accessible to me during a day sail from Redondo Beach has a depth of 650 m or less.
Bob is also a testbed for a more ambitious autonomous vehicle that will use those capabilities.
It is programmable, but usually a half hour.
The salt dissolves in a few hours so if Bob's batteries have died or its mechanisms fail, Bob will still surface. Plus, I'd rather not leave piles of metal trash scattered on the ocean floor. And, no, steel will probably not just rust quickly away. There is very little oxygen down there and a lot of sedimentation to bury stuff quickly.
That would force me to try to hold my sailboat in one position above Bob. Sailboats aren't good at that. An earlier version of Bob had a cable tied to a buoy, but the cable kept getting in the way, tangling on things and trying to drag Bob along the bottom as the buoy drifted.
Yes. Mostly I just hear the sounds Bob makes, but I often hear fish bump the camera as they pass, plus snapping and barking sounds from shrimp and, I presume, fish. I've also heard passing motor boats overhead and what sounded like an intermittent dentist drill. Bob was a mile or more away from shore, so I have no idea what that drill sound was.
It is configurable and depends on how much salt ballast has dissolved, but generally from 0 to 10 meters.
It is fairly easy to hack the electronics and control it the way I want to. The next version will have a better low light camera, however.
The GoPro needs a fair amount of light to see more than a half-meter or so. So that means a lot of power goes to the LEDs. The LED heatsinks get untouchably hot after only a second or so. Thermal management concerns and battery limitation reduce Bob to only flashing the LEDs for about 1 second out of 10, mainly to keep the internal temperatures under control. I'm experimented with other lighting arrangements - I have some deep sea fishing lure lights - that provides the dim green images of fish close up. The next dive will use full-time dimmer lighting between flashes.
I've found that when the light hits right in front of the camera, the debris in the water tends to trick the camera into adjusting the gain for that and stuff father away becomes difficult to see.
I've never added up all the receipts, but I would guess $3,500. Many of the specialty parts can go much deeper than 750 m, and so are more expensive. The syntactic foam I picked up second hand for $700. The instrument housing, camera housing, bulkhead connector and frame parts were several hundred dollars each. Maybe a hundred more went to Mouser and Digikey for all the electronics. Plus I've made probably 50 trips to the local hardware store for various bits like wire, paint, screws, PVC pipe, etc.
Well, so far it is a lot of mud, to be honest. But there also are prawn, flounder, rock fish, jellyfish, worms, rays and other unidentified stuff down there. Most recently, Bob hopped into some sort of a fish nursery with thousands of freaked-out baby fish.
This is an often-repeated myth which the oceanographic community, jealous of space program funding, uses to argue for more money. There have been only twelve Apollo astronauts as compared 14,000 people on just the Alvin submersible. We have returned about 385 kg of the moon for study (and none from Mars). A single research ship can return that much mass in cores on a single voyage. The Mars rovers together have covered < 100 km total; a towed drag sled can cover that in a day and return video to boot. We have books, conferences, aquariums and research programs devoted to the study of benthic life, vs. only speculation about life off-Earth. We should explore both space and the seas, but oceanographers have it easy. Although, on the other hand, astronomers don't get seasick.
None, Bob needs simplicity, not unpredictable complexity, in that unforgiving environment.
During some testing at my marina, Bob did accidently find the marina's sunken dock cart which we later retrieved. Otherwise, no, I'm on the wrong coast for Spanish galleons.