I thought of something similar a few days ago (given I will be single
But rather than a GoPro, I thought about a Lowrance Elite 3X Fishfinder
instead. Can put mounting brackets on the Pulpit and have it on the end of an alloy pole (cheap) facing forward under the water at about a 45 degree angle.
I like the Lowrance Elite 3X Fishfinder
because it has a 20ft lead, and you can get a 15ft extension (which is then easy to make even longer if necessary).
Easy to demount and then use wherever I like (even on the dinghy).
It's pretty cheap
too (I've seen it retailing for $94 US).
Should be ok with a slow and steady approach? I think up to 800ft effective range might well be enough to be advantageous, plus it isn't so vulnerable to murky water.
PS. Would one with CHIRP offer any significant advantages? The cheapest CHIRP ones aren't that much more expensive.
PPS. 'Might' be handy with any issues with the anchor
too (which perhaps says 'go for a CHIRP model').