Homebuilt ROVs Forum

OK, got the new prop printed (6 blade) and it's giving a little more thrust at about the same draw. This one was up to 123 grams of thrust at about 1.32 amps of draw.

Also, switched to a 30 gallon tub instead of the one I was using (about 5-8 gallons I guess). I was worried that the small tub was setting up currents that were messing with my readings. This one looks like it's got less turbulence and I'm thinking, more like an actual dive environment.

Still not sure if longer prop blades or more blades will give me more thrust.

Tomorrow I plan to print an 8 blade prop out with all other dimensions remaining the same and see how that goes.

So far, not really drawing much in the way of total power, but just by eyeballing it and feeling how much thrust is coming from it, I'm thinking it's close to enough to move a small ROV around pretty well. If that's the case then there will be an option for powering a small one without having to expose the motor to the sea!

More to come...

PS- I shot some video but the frame rate of the camera is just about synchonized with the prop speed so it looks like the prop is slowly moving backward! It's like when you see a car in a movie with wire wheels going slowly and they look like they're spinning in reverse. It just looked strange.

Hey everyone,

So my design is starting to come together. I still have no idea what it's going to look like when it's done. I'm trying to let the design requirements and whatever decisions they lead me to, determine the basic design.

So far it looks like it's going to be a schedule 40 main pressure hull either 3" or 4" with some outriggers to the sides or below it for the thrusters. I'm hoping to get the mag-coupled thruster design far enough along in the next few weeks to start designing the actual structure of the ROV.

Today's post is in response to a brief conversation I'm having with Moki about his design.

This is a sneak peak into how I plan to deal with the endcaps: Cherne keys with the wingnuts removed (replaced with nuts) and with caps on the end to make it a bit more hydrodynamic. Someone else on here (sorry I forget who) is also using the cherne key idea and I took it from there.

So the idea is this: Remove the wing nut from the plug (cherne key) and replace it with a SS nut of the same thread. Before putting the nut on though, install one of these 3D printed end cap/domes. This will make it more hydrodynamic and also keep it from getting tangled. The caps allow water to flow through them and will drain as soon as you take it out of the water.
Once I test how tight they need to be in order to work at the depth I plan to dive at, I will record that and use a small torque wrench to tighten that nut each time so I know it's the same each time.

Here's a 3" cherne key - unmodified



Here's what it would look like with a cap on it:


I am using these for the thrusters as well, so I have some that are 1.5" diameter as well (sorry, the print was messy, need to clean it up and paint it, but you get the idea):



end on view (you can see one of the 3D printed bracket sets I'm working on too)


Tighten it to spec...



A couple of printed end caps...



What does everyone think?

I like it! For sure it will help with the hydrodynamics and looks as well