I am a licensed Texas security
company and specialize in video surveillance. The variety of what is available on the market now is mind boggling and ditto the prices. I don't mind giving advice to fellow cruisers on what to buy and how to hook it up. It isn't terribly difficult but there are things to consider like specialized tools (depends on system type) and filtering the marketing
b.s. from reality. And, as in many markets, your lack of knowledge can really cost you $$$ if you don't have an advocate.
If one really wanted to, he/she could have a 360* masttop camera
for looking down while navigating through those pesky coral
heads or underwater cams at bow, stern and to the sides... The combinations and posibilities are limited only by your imagination and, to a lesser degree, your budget