I will tell you one thing that works.
I have a Sony Handycam underwater housing.
I took off the lead base weights and pistol-grip handles which are obviously not required if you are not diving. This left the basic waterproof barrel of the housing.
I put my current video inside and strapped the assembly to sling BELOW the A-frame. The straps I used were normal thin adjustable types. I used two of them to give an "infallable" grip.
The camera was lined up to point ahead of the boat at a reasonable distance and then operated (film/pause/stop/rewing etc.) by means of a credit sized remote control that was supplied with the camera. Thus you can helm and film single-handed.
The video footage is surprisingly "forgiving" in that it doesn't shake as much as you think it might.
I used this system to film Mr. Priddy and co. off Start Point when they crossed the Atlantic in "Spirit" the last time.
The footage of the whole crew mooning at the camera will doubtless provide me with a decent income in my later years.