While it is nice that the owner is addressing the issue, this is one consumer who wouldn't be so quick to give him a pass. To me the attitude of everyone associated with the business that day doesn't give me confidence that I would risk a single day of an 8 day vacation on again.
The degree of information (read lack there of) and handling of the situations with the consumer is quite troubling.
From someone who's worked in the customer service industry (in several different types of jobs), information is key and "I don't know" by itself is the most negative thing that anyone can tell a customer. "I don't care either" and "I'm not going to do anything about it " automatically gets read into the exchange! I always tell my people that they need to qualify the statement with why (if there is a legitimate reason) and what you're going to do to get the info or when the consumer can get the info. It gets even worse when someone who doesn't know says "Dunno". Now you have incompetence read into the exchange.
It is one thing to give truly competent people latitude to do their jobs, but here it sounds like you may have not even vetted your people well. The attitude of your workers doesn't seem to be encouraging either.
Yes, it is your job to drive the boat and you may not have very much time to interact with your customers during the charter, but you should be taking the time out to hire well and train your workers to be the kind of frontline people who represent your business properly. If you cant, then you need to hire those who can and will.
I hope for your sake, you do really take the steps to do better and attract those dollars that are votes in our free market economy. Lord knows, we need as many dive shops here as we can possibly get!