Unmanned Submarine

Not sure how well the GPS will work underwater. H2O is a great attenuator, that's why subs have to send things up to the surface to establish communications etc.

There was a documentary I watched a couple of years ago where a group created an autonomous sub and sent it across the Atlantic on its own none stop. Cant remember the name of it but Im sure a Google search would soon find it for you

I looked at their project and yes the gps signal would have to be transmitted once it surfaces.  Probably have to program some dead reckoning type logic for the subsurface course.  So I guess it would also require a compass and a way to measure drift/current/speed.

Quad Copters have all the sensors you may need

Accelerometers to detect drift and turns to help with direction and inclination, barometer for depth sensing or other model pressure transducer

GPS for when surfaced to re-set the dead reconing system

How deep are you planning on going with this

Yes I also found a trial test of the glide type AUV's (like the one Rutgers launched) which listed the manufacturer of the electronics they used.  Checked their website and waiting on some pricing.  Only plan on going as deep as needed to avoid boats and shipping, so prob 50'.

Actually depth will have to be variable due to reefs and shallows here in South Florida until out in open water.

50' is a lot of pressure, meaning thick walls and less room for kit

Waterproofing will be a big challenge as many parts will require external mounting with holes for wiring to get through to main part of sub

50' is a lot of pressure, meaning thick walls and less room for kit

Waterproofing will be a big challenge as many parts will require external mounting with holes for wiring to get through to main part of sub

Made a propulsion type system once for diving using PVC and lexan.  It was able to stand more pressure then I will need at 50' little less than 44 psi.  Yes it will be challenging to maintain water tight integrity with any penetrations so the fewer the better.