In the Mid Atlantic up to Maine, I would suggest that Comercial fishing boats i) look mostly at radar, ii) they don't have their AIS on that often, and iii) in limited visibilty, they would be looking at the radar.

Smaller (like lobster boats) would be looking at radar in the fog. They almost never show AIS.

Sport fisherman with commercial captains delivering luxury boats for their owners probably have both and are watching them -- if they're watching anything offshore. They usually have their AIS units up, in my experience.

Big ships seem to have AIS units on. They don't spend a lot of time looking at us; however, when we hail them it is rare that i) we don't get a response back; and ii) they can't immediately recognize us.

Often I've been spoken to by commercial vessels when transitting. They know we are a sailing vessel from our Class B unit, and they want to make sure what our intentions are if we are an issue for them.

Of course, there are other times when bigger, fast moving ships, don't seem to care what we're doing -- however, I haven't had the experience of not having a repsonse when I hail someone.

I have spoken with people that say they have not idea if anyone is on the bridge offshore -- I just haven't had that happen.

As for our transponder on the X band -- I don't have a transponder, just a passive Lensref located about 50' or so up in the air on the front of our rig. Almost every ship has said they get a decent return from me -- but some smaller boats don't get returns that far away. Then, again, some amazing large, steel fishing boats don't seem to have that good a return at 6 miles. (Our Furuno 24", 4KW, HD radome is about 14' off the water on a Questus mount with a long extension tube.)