Not commonly used
Sound signals seem to be a thing of the past, and are not commonly used in the area, and should not be relied upon in any way. Rules are often written to reflect what has become common practice, and I imagine that one day the sound signals will be dropped. It is not, therefore, not "totally irresponsible behavior," and with the expectations based on common local practice, shouldn't be "very disturbing and somewhat unsettling." It is just the way it is. The U.S. Navy doesn't even use sound signals in these conditions in this area. For reference, the International Rule related to this is: "(c) A vessel not under command, a vessel restricted in her ability to maneuver, a vessel constrained by her draft, a sailing vessel, a vessel engaged in fishing and a vessel engaged in towing or pushing another vessel shall, instead of the signals prescribed in paragraphs (a) or (b) of this Rule, sound at intervals of not more than 2 minutes three blasts in succession, namely one prolonged followed by two short blasts." "(d) A vessel engaged in fishing, when at anchor, and a vessel restricted in her ability to maneuver when carrying out her work at anchor, shall instead of the signals prescribed in paragraph (g) of this Rule sound the signal prescribed in paragraph (c) of this Rule." (http://www.uspowerboating.com/USCG_Navigation_Rules.pdf linked below) There are also two blast and four blast signals, for a power driven vessel underway but making no way, and a towed vessel, respectively. But, no one around here uses sound signals anymore. Captains refer to the signals in their dialogue with one another, as in "I'll see you on two whistles," but they never sound the signal. The only times I've ever encountered a sound signal were first, entering Nantucket harbor and being overtaken by a mega-yacht in the channel, he sounded one whistle, which I answered; second, coming abeam of a U.S. Navy sub which I had communicated with, in heavy fog, through "The Race" at the end of Long Island - he gave us one long blast, as courtesy, I think. Likewise, one seldom sees anyone, and almost never yachts, using day shapes, such as the anchor ball (daytime) or the cone for "under sail when also being propelled by machinery." I have only seen dayshapes used on large, fancy sailing yachts that were obviously charters. In poor visibility securitie calls on channels 13 and 16 are commonly used. AIS is in use now, so if your chartplotter supports it, and you get the approximate $200 receiver, you can see the big stuff on the chartplotter. So, use your radar and the VHF and AIS, and look out!
