Adjustable ballast system?

[bshey]

Hi all, I was just wondering how ballast systems generally worked. This is my first rov bulid and am therefore very inexperienced.

Please correct me if i am wrong or if this wont work:

There are flotation pods at the top of the rov. The bottom of the pods are open. compressed air runs down the umbilical and enters the pod pushing water out the bottom. This increases buoyancy. there is some sort of solenoid valve (which ones would work???) at the top of the pod that can be opened to release the air and fill the pods with water again decreasing boyancy.

Is this the best kind of buoyancy system? thanks.

[thegadgetguy]

Most home built ROVs don't have a buoyancy system that actually changes the buoyancy of the ROV; are neutrally buoyant, which means that when placed at any depth, they will stay at that depth until the vertical thruster gives them a push up or down. A ballast system that uses air as you asked about in your question is certainly possible, but much more complicated because of all the additional components, such as solenoid valves and compressed air. Unless you plan on picking up really heavy objects, or have some other reason to go with a variable buoyancy system, it's simpler and less expensive to go with a neutrally buoyant ROV.

Good luck on your ROV, and welcome to the forum!

[Never prototype]

If your using compressed air at the surface why not use a valve or the psi regulator or the on off switch on the compressor to control depth? 30 feet equals one atmosphere about 15 psi. So you could raise your rig from 200 feet down with 100 psi in theory. You could put a pump onboard and fill your ballast tanks with water to dive and simply pump the water out to surface like a real sub does. Extra style points for this method.