Pieces and Parts (Concepts first!)

I've been sifting through every ROV page on the internet - when I "came up with this idea", I thought it'd be few and far between, but the amount of pages out there on homebuilt ROVs is insane.  Information overload for sure.

I've come to a design crossroads.   I originally planned on doing a 500 foot tether, with multiple cables connected so I could just do relay controlled thrusters, passing power down through the same tether.  As I considered that, and it's not a horrible idea by any means, I grew weary of multiple connections going bad and leaving my ROV sitting on the bottom of the (ocean,lake,stream,pond,pool,bathtub) to die a horrible, rusty death.

Plan 1:   Buoy "Platform" on the surface, with 100 foot tether to the ROV, and tether to shore.  Kind of a relay station idea.   I liked this idea, but again, too much old school electronics, and I really don't want to drag huge lead acid batteries with me everywhere.

So here's the real plan;

Buoy platform on the surface, with 100 foot tether to the ROV, but with wireless network connections on a small antenna pole.

Buoy Contents

• Battery System (NiMH ?  LIPO? )  Haven't decided here, because LIPO is hazardous near water...  extermely so...
• Battery Charger port behind weather protected cover.
• Raspberry Pi on board for tech measurement, and app connection to shore
• Mikrotik HomeAP running in AP mode (connection to shore)  Might possible change this out to support a connection further from shore
• TPLink Powerline Ethernet with guts ripped out (power it via battery, 3.3v) and will connect to tether to 
• Massive flotation.   Positive Buoancy
• Surface to Air protection ?   hah.  Nah, that's a different day.
• Beacon light.
• 100' of Cat5e, gel-filled, attached.

ROV Platform Contents

• Battery system, definitely NiMH, with charging system, mounted inside pvc tube filled with mineral oil.   This will avoid leakage at pressure, and also protect batteries from corrosion and (salt) water leaks.
• Mikrotik HomeAP on board as the network controller / switch.   5 network ports, 1 for uplink, 4 for devices on board.   It also has WiFi built in, and I was thinking of connecting the PI's to it via WiFi.
• Raspberry Pi on board for motor control and possibly cameras.  That might mean three PIs.  
• Some sort of network camera(s) - would like front / rear.
• Neutrally Byuoyant so as to be able to move up / down all around easily.
• Torpedoes on board.  OK, different day still.
• LED Light platform

ROV Structure

• Need two 3" PVC arms for the battery storage.
• Need central (4"?) PVC for the guts / motor control, etc.
• Bilge pumps serve as motors - I thought I was going to stick to the jet boat design, but to save amperage, and only use 3 motors, they have to be dual function.   So, I'll break them apart, and adapt props to the shafts like everyone else does.
• Some sort of rope, or stronger tether needs to connect Buoy to ROV, so if we had to we could yank it up by something sturdy instead of yanking on the cat5

That's all I can write for now, but I'll continue with more thoughts later.