Now Now Bill you know surface runners run into subs even without a towed array.
Gazza Radio gear do`s work under water as long as you dont try and use 2.4 gigs as the signal will not penetrate water. Model submariners use 40 megs and you have full control of the sub down to probably 15 ft unless the water contains a lot of particals , is salt water or even swimming pool water they all reduce the safe controlable deapth you can go as to FPV with a sub water is not as clean as air so unless you are in a swimming pool or fresh clean water you wont see much anyway best way to see whats going on under water is to fit a keyfob typ camera into a water tight container recording onto a micro sd card and watch it later
Regards Mark