Re: who had right away?
First, neither vessel had "right of way". That only applies downbound on the Western rivers. Read the NavRules.
Second, a lobster boat underway between traps is not, per the rules, a "fishing vessel" and has no special privileges.
Which brings us to the rule that applies here. The power vessel is obligated to take early and substantial action to stay well clear of the sailing vessel, which in turn is OBLIGATED to maintain course and speed. At least until it becomes clear that action by the give-way vessel alone would not be sufficient to avoid a collision.
This is all just NavRules. Everyone should know this.
Now, some reality. Lobster fishing tends to require frequent course and speed changes. As they move between their gear, they may appear to be steaming quickly toward you, then suddenly slow and veer off. Don't plan to far in advance to take evasive action, it may not be necessary.
Also, from the lobsterman's point of view, sailboats may also appear unpredictable. You'd think he'd figured out that you weren't about to tack, but trust me, he's seen his share of sailboats cutting right in front of him for no apparent reason. He's going to go about his business and pretty much ignore you until it's a crisis. And as a guy who's used to pulling up to within inches of a buoy, all day, every day, he knows just when that is.
As for this case, it's also possible he was just messsin' with you because he saw you were confused. Not saying it's right, just that it happens.