This is what I am having trouble understanding. Boats have mechanical issues on occasion. The operator gave them the choice of a refund or a spot on a different boat, which not surprisingly, was crowded (given that two trips were combined)
I'm not sure what the OP would have expected.
Bear in mind, I don't know if this shop has a habit of poorly maintained boats and so on, but if they do, then it might have been better to book a different shop.
I'm not sure it's fair to say they "chose money over safety". What was unsafe? Crowded isn't unsafe, it's just inconvenient. "Unsafe" would have been setting out on a boat that was having mechanical issues.
My observation from a long way away is that the operator responded to an unforeseen mechanical problem in the only way they could... refund or a different boat. What else could they do?
Admittedly, perhaps some more preventative medicine might have avoided the problem altogether, but salt water does kinda eat stuff.