No Name ROV

[Pilikia]

SoakedinVancouver,

You will find both recommended and minimum system requirements for your operating system at http://sketchup.google.com/support/bin/ ... swer=36208

[Pilikia]

After too long in the virtual world, I have begun assembly. What appears to me the trickiest part is getting the cameras to do their tilt thing within the tight confines of a 4"(nom) PVC tube. So I tackled that first.

One of the requirements for me is to be able to easily remove the Contour HD 1080p so I can continue using it while diving and snorkeling. In order for it to go into its very tight-fitting underwater case, it can have no external attachments. So right off the bat I have seemingly funky velcro and a rubber band. (I have no immediate plans for either duct tape or baling wire, but you never know!) Actually, it seems to work very nicely, and the Contour is easy to remove, and still slips into the waterproof case used for diving and snorkeling.

The controller for the servo doing the tilting has a very tiny 1/4" knob to turn to change the vertical angle. It's really too small for doing very fine adjustments smoothly. I'm making an extension with a much larger knob, and stop-posts at both ends of the range of travel the design can tolerate.

The image on the monitor is from the tiny camera attached to the Contour. It is very wide-angle, which I think is good thing. This monitor and camera are intended to be used to provide a driver with rear-view video for backing up safely. I found them new on eBay, shipped direct from China.

Anyway, here's a video of these components working together:



The soundtrack on the video is inadvertent, coming from the TV in the background.

[Pilikia]

I finally got around to doing buoyancy calcs on the revised design. I was shocked to realize it was more than 10 lbs positive buoyant! I have changed the 3" dia. upper hulls to 2" ones. It's now about 6 lbs net positive buoyant, which seems like an acceptable amount of ballast to add.

[wolfenstien]

Looks nice. Looks alot like a star trek ship without the bridge section. Ocean the earths final frontier.

[derelicte]

six lbs still seems like a lot to me. you are just going to waste energy moving that ballast around.

You could try shortening the buoyancy tanks as much as possible to minimize the ballast needed.

[Pilikia]

derelicte, good eye! You are exactly right. I was able to reduce their lengths by 3.5" each. This reduces total volume by 31 cu. in. and reduces total vehicle weight by 0.4 lbs. The net benefit is ballast is reduced to 5.33 lbs, a roughly 12oz reduction. Thanks!

Here are before and after port side views:

[martinw]

I might be wrong but the flow of water from your vertical thrusters looks like it may well be limited by the camera housing beneath them?

[Pilikia]

martinw, hmmm . . . it's a good question. I'm really not sure. There's ample space for the water to escape, but the water being deflected by the curving hull might rob some thrust. Maybe making a test setup wouldn't be too difficult. Or I could just lengthen the nipples at the top saddle tees to raise the whole assembly an inch or so.

Thanks for bringing it to my attention. Anybody else have an opinion?

Here's a view looking from the front down the length of the hulls, which helps to visualize what's going on.

[derelicte]

you could also shorten the fat end of the reducer that the motor fits into.

In the end it may not matter, though. the motor itself is pretty fat and it doesn't seem to really effect water flow to or from the thruster.

[Pilikia]

derelicte,

I gave your suggestion a try. It proved difficult to do. I cut down the length of pipe glued to the motor housing, the length of the bushing, and the length of the coupling that fits over both of them. What I was left with proved really difficult to assemble. Those slip connections are slightly conical, and trying to insert them when they've been shortened isn't as easy as it sounds. I made a mess of it.

BUT I finally found a source for 2" x 3/4" reducer couplings (not bushings) - the kind with a conical section between the 2 sizes - which is really what I wanted in the first place. It'll provide the hydrodynamics I was trying to get with the little domes I've been showing. I haven't received them yet, and am not certain what their overall length is. I should know in a week or so.