Ever since I discovered the article about the $99 home made ROV, I’ve been all excited about building my own and using it to attach decent lines onto wrecks that are below 300 feet. In other words, wrecks that are deep enough to dive on technical scuba, but too deep to spend bottom time searching for. Since the $99 ROV does not have thrusters, I set out about finding a way to build some when I discovered Doug Jackson’s article about his adventures building this ROV named BOB. I have say, I really like his design! Not only does it use reasonably priced parts, but he’s been very clever in how he has used modified vintage Atari video game controllers and relays to drive the thing.
Here is a quick overview of what he has used:
- Five, 500 gpm Johnson Bilge Pumps as thrusters. He got them for $10 each, but they now cost about $20 when you buy them from Boater’s World.
- Atari vintage joysticks from eBay
- PVC pipe, epoxy, wire ties, and Cat 5 cable from the local hardware store.
- A 9V battery to power the relays
- A 12V battery to power the pumps
- An Atlantis™ Guide View Underwater Camera System
- A television to serve as the monitor
Doug provides very detailed directions on how by constructed BOB, and even talks about how a person might modify the pumps to be fitted with propellers, thereby making the ROV more effective in areas of heavier current.
In BOB’s lake trial, it was tested to 60 feet and performed well. A neutrally buoyant tether cable was obtained by attaching 1 foot sections of foam pipe insulation every 6 to eight feet. Telling how close the ROV was to objects was apparently difficult, and Doug mentions that it either needs better lighting or lasers that cross 6 feet in front of the device might be of help.
Here are some direct links to areas of interest on Doug’s site:
- How to Build Your Own Underwater ROV
- Using Thrusters With Props Controlled by a Joystick
- Increasing Thrust with Kort Nozzles
Again, I really like Doug’s design. I think the most challenging improvements would be to increase the thrust by using propellers and to prevent the pumps from flooding under greater pressure. I’m also not sure about how one could manage the voltage drop over a longer tether cable. I don’t believe the design, as it is, can make it 400 feet down to the S.S. Tahoe, but I do see it making the dive with some HID light, tighter seals, and a little more thrust.
What about using one or more motors & propellors from cheap electric trolling motors? You should be able to get your hands on a cheap one with 50 pounds of thrust (which easily pushes a 15 foot boat around) for not too much $$.
That’s a good idea… There can be no doubt that it would have the thrust needed to battle currents. I wonder if the seals in those motors can take 400 feet? It would be like a little ROV race car!
Actually I’m not sure you have to worry about seals; it’s been a while, but I do remember hearing at some point that 12 volt motors will continue to work underwater because the voltage isn’t high enough to cause shorts through water. I’m pretty sure that was on an episode of junkyard wars where they were making torpedo propellors out of car radiator fans.
[...] While I hate to see these creatures dragged up from the abyss, I am very much a “deep junky”, and take great delight in learning more about marine life from the murky depths. Mostly, it is for this reason that I have developed such a strong interest in both powered and unpowered DIY ROV technology. [...]
[...] The current project in my mind for which I think this service might be of use is homemade ROVs, but I can see a million and one uses for hassle-free custom part machining. [...]
We are working on designing some low cost solutions to the hobby ROV thruster problem. If anyone wants to get involved, please head over to http://www.torrsys.com/rovthrus.htm and give us a little feedback. Thank you.
^_^ Hi…
I have planned to make an ROV to. And i used computer fan as thuster + propeller. It was, a great day to visit your project blog.
thanks
i wud lyk to know abt the thrust available by using computer fans as propellers for my rov .wud it be gud enough to go down to depths of 1metre.plzzz reply soon!!
You can fill the trolling motors with mineral spirits or transformer oil. Then seal off the opening. You don’t have the problem with water shorting out the motor and you also eliminate pressure problems.
Small 12 volt DC motors run in fresh water quiet well. I run them under water to break them in for my RC air planes. HOWEVER,, Salt water does carry current so I would advise you fill them with oil as suggested. BUT it must be light oil or it will cause a LOT of drag.. IF you use a 12 volt DC trolling motor NEVER run it out of water expecailly filled with oil..It can heat up quickly and the oil inside may hurt you..Then again for short burst’s the oil may keep it cooler than no oil. BUT I mean short burst’s like less than one minute..This idea is very interesting to me. I just built my own shallow water diving system and am continually trying to improve on it…
use 2 cameras to get depth perception