done it anywhere from 20m (local) to 70m (coral bay). tried in 110m to test and busted the lens due to pressure(was cheap $20 model so didnt care). says max 30m but as said have gotasdeep as 75m.

learnt so much re the ground at coral bay and how to relate to sounder, good and bad, and particularly where the reds hide!!

I just cable tied to main line and swivel and had baited rig!! 

will try and get up here one day but couldnt embedd video and havent put on youtube or similar.

Have a look online for the Fishermans Eye, its a purpose made bracket for mounting a Gopro and sending down on your rod. Keeps its perfectly balanced and upright which is the key. 

I use it before diving deeper ground to check out the visibility at depth, you can then use the bluetooth between the gopro and your phone to check it out as sson as you pull it up.  

My young bloke rigged up a GoPro with just a swivel on the top and bottom of the waterproof cover and a big sinker on the bottom. The footage was a bit spinny, so a fin could help - but not bad for a first try. 

He got some interesting footage down here in Albany last summer:

https://www.youtube.com/watch?v=hN1kY-4Z27g

https://www.youtube.com/watch?v=IAPZ9dE1v7Q

We have been doing it for a long time now. 90mtrs is the max. Fisherman's eye is good. don't need it. They work well for what they are. Good to test your sounder to know what shows up and what is on the bottom. You will be surprised the amount of coral and reef system we have out there. Also good to watch the footage when you get back over a beer or 4! 

Have a look at the bloke in QLD with the underwater Drone! Looks good. 

 I attached my go pro to the flat mount that they are shipped in and then screwed that to a dive weight and sent it down. I had a little bit of bait on it too but all i saw was butteries.

I also did it in broome on a pole in 8m of water which happened to get stuck under a rock. After a moment of sweating bullets i managed to dislodge it. 

 Just don't let too much line go slack and allow the go pro to hit the bottom and get snagged under a ledge, I lost a brand new gopro 5 thinking it was just the sinker snagged and locked up to break it off, but it was the gopro snagged :(

Cheers for the replies folks and the vids I think ill get the fishermans eye and se how it goes,and it has the float on it too. My gopro case is supposed to be good to 60mtr so ill be interesting. Mainly on looking to compare the marks and ground to what Im seeing on my screen. 

 A bit mate, better structure less fish, my thoughts hammered ground. We fish within 10-12 mile north or south.

best for reds is gravelly / low what looks like limestone ground.

I made a mount for mine out of 20mm flat steel I had lying around, basically a flat base and an arm for my camera to sit on, retro fitted a small pole with a pouch for bait. When I found a new lump I threw it over with rope and float and came back later to pick up, did a few drifts over whilst it was filming. I even saw myself hook up to a dhuie as my line came past. This was out of Mindarie in the 40mtr depth, very surprising what I saw on the footage. Also helped me understand my sounder a hell of alot better.

 I made a little tripod years ago that we would drop to the bottom while yak fishing harbours. We'd jig and drop baits around it then watch footage when we got home and think why the hell we couldn't catch those fish!