Just wanted to share a pic of the 3mm plate aluminum body completed today. It is based on the 2.8 shell but has been expanded to allow for top mounting payloads as well as attachment points for more ballast and buoyancy (to come soon). This lowering of the center of gravity as well as raising the center of buoyancy will hopefully allow the ROV to be more stable under thrust and more resistant to the large predators we have out here (which this could literally fit in their mouth).
Impressive! I like it a lot. How exactly did you manufacture it. Some questions came to my mind: Did you laser the parts? What is the weight of the construction? How do you want to reach neutral buoyancy? How do you want to account for the added load regarding operational speed?
At the moment I’m not too concerned about the top speed, just durability and stability. I will be mounting stainless ballast tanks on the top corners with adjustable position lead weight “foot pads” at the bottom to allow for off-balance loads and greater stability around the central axis. Like I said, top speed is not an issue at the moment, but I’ll let you know how it performs in the next couple days. My hope is that the much higher mass will affect the acceleration only and still preserve maneuverability. The increased vent areas on the top and sides around the motors are to allow for increased flow to the props. I’ve also reversed the battery tubes so they are back loading, as they presented a bit of a bumping hazard in the front (and the aluminum cover pads could be used for mounting hardware in the future. Exterior lights are planned for the underside of the top canopy forward of the pressure vessel but still protected.
I get the idea I especially like the idea of a much more robust design that enables more interaction between the ROV and the environment. For example that you are able to slightly bump objects of interest. I also think that loading the battery tubes is a smart idea to increase the tubes stability especially with that extra protection of your shell. I slightly hit the river bed once and got a leakage in one battery tube.
I however feel that the impact on maneuverability will be noticeable due to the greater hydrodynamical resistance and weight. Keep up the great work and please keep posting updates, I am looking forward to your built!
Thanks for sharing! I can’t wait to see more pictures as it comes together!
really beautiful job !
Thanks for the encouragement guys. Just an update, I’ve taken it out several times now and an very happy with the results as far as speed and maneuverability. Obviously it is slower than the original spec, but the stability has gone up tenfold. Under thrust it has no appreciable “bucking” and turning at slower thrust is very precise. Having the buoyancy and ballast as far apart as possible has probably been the biggest contributing factor, but the additional mass acts effectively as a dampener, softening the “jerkiness” that can come from the lighter chassis. I’ve modified the shell further and painted it, and I’ll post some video next week when I take it out to some deeper water.
Wow, very impressive! Great job.
Clever use of aluminum water bottles!