Radio-controlled submarine

Content sourced from Wikipedia, licensed under CC BY-SA 3.0.

Radio-controlled submarines are scale models that you can steer with a radio transmitter. Hobbyists build simple toy versions or more complex ones with electronics. In professional use, submarines are often called remotely operated underwater vehicles (ROVs) and are used by scientists and the military.

Radio signals don’t travel well underwater. Lower frequencies penetrate water better than high frequencies. Hobby models usually use bands around 27–40 MHz, which can reach only a short distance in fresh water. Modern 2.4 GHz control systems don’t work well underwater at all, so the antenna must stay dry and well insulated. The wire that carries the signal should be sealed at any exposed end to keep water out.

There are two main ways hobby subs control depth. Dynamic diving models stay buoyant and dive using thrust and trim changes; if radio contact is lost, they naturally rise to the surface because they’re positively buoyant. Ballast-based models change their displacement by taking in or releasing water.

Ballast systems can vary:
- Ballast tanks fill with water to dive and are emptied by releasing air or using pumps. Some designs use a vent at the top and a pump or compressor to push air into the ballast to expel water and rise.
- RCABS (Recycled Compressed Air Ballast System) uses a bladder that’s inflated with compressed air from the watertight section of the sub to increase ballast and dive.
- Snort systems vent air into ballast to submerge and then use a small air pump to expel ballast and rise.

Advances in small computers, like Arduino and Raspberry Pi, let submarines operate autonomously when radio links are weak or visibility is poor. Many models also include safety features to prevent loss, such as depth limits and systems that surface if control is lost.

Overall, RC submarines range from affordable, simple divers to complex, option-filled machines that mimic professional underwater vehicles.