Most of my background in making securite calls has been aa a professional mariner. But they're applicable to all of us.
On ship's we'll commonly make them when steaming in fog or otherwise restricted visibility; yes even in the middle of the ocean with no one apparently around and the radar going.
Most ships do not slacken speed in fog in the open ocean. But, if you read the Colregs and read them for intent, you'll see that all means are required to ascertain the presence, not only the position, of another vessel. And you've got that VHF hanging there on the bulkhead that your owner has already paid for and you're not likely to wear out. Besides, you're on watch with little else to do, so you might as well talk to the ether. Here's the deal. Run down an unlit and disabled fishing boat, you didn't pick up on radar, and at the RS 4450 hearing they're going to take that four hour watch you stood apart right down to the brand of coffee you were drinking. It just makes sense.
That brings me to the topic of sailboat batteries. It's been my experience that most sailboats, offshore, will shut down a lot of electrical drain. VHF and running lights. That's fine as long as you're keeping a good watch in the daytime and you have them on at night and in restricted visibility. A lot don't. And that's dangerous. You need enough battery and charging capability to be able to at least hear my securite, if not make your own. The "SS President Madison at Lat/Long on a course of 265 degrees at 25 knots" is fully capable of ruining your day, in less than an hour. Maybe less than 10 minutes. What else were you going to do with those batteries?
On a ship at sea, I'd make a "CQ", or securite, call every 15 minutes in fog. I'd expect a sailboat would want to every half hour to hour in similar circumstances.
In port and during manoeuvering we'd make one just prior to undocking and every time we entered a new channel or the conditions warranted. Most recreational boater's probably ignore them; sailors should know better. If you hear, "Securite, securite. This is the Chevron Hawaii inbound from sea, bound for the Richmond Long Wharf, abeam of the Golden Gate Bridge, standing by for all concerned traffic" you'd might consider figuring out where the Richmond Long Wharf is on your chart and what route she'd be taking to get there. What you don't know, but intuitively need to know, is that she's an 80,000 ton tanker constrained by draft and she won't be giving way out of the channel. You're not really expected to exchange passing information with her about where you'll meet under the Bay Bridge, the better part of valor perhaps laying more along the lines of ensuring you're not where she's gonna be. A good time to navigate out of the channel, because you pretty much know she's not going to chase you into shallow water, or heave-to out of the way for a cuppa Joe. You really don't want the experience that bubb2 described, where you're so close, you're under the light pattern of her running lights. The only thing worse being, thinking you "know" where she is and having 800 some feet of steel go sliding by close aboard. You'll think it's never going to end.
Don't get me wrong. Ship's want to hear from you, ESPECIALLY out in open waters where you might well be hidden from radar by the sea and swell. They just might not respond to you specifically in inland waters because basically their course is set, they have no options as to where they can go. They can stop, temporarily, but the minute they do they risk wind and tide carrying them into shallow water and running aground perhaps.
they're going to assume that you'll keep clear of them.
The trade-off is that out at sea, they'll stay well clear of you and in confined waters it'd be nice if you stayed clear of them.
Guy's sometimes get a little goofy when racing. If a bunch of boat's decide to have a race it's real good idea to notify the pilot boat or the pilot station, or port control. Failing that, a securite broadcast is a good idea. Here's where the racer's get all po'ed: that tanker isn't stopping for your race either, unless you've done the really nice thing and notified the pilot boat in time and he can lay-to outside for 15 minutes until you clear the channel. It's all just a nice polite thing to do, on both sides.
Never assume either that the securite conversation you've just had is with the ship you see a mile away until you can positively identify him by name of stack insignia. You might well be talking to a very nice gentleman from Austrailia while you're about to have a close quarters situation with the M/V Bonzai Express. It's also not a bad idea, out at sea, once you've exchanged your securite greetings with a ship to ask him about any other ship's in the area he may have on radar. He's tracking them 24 miles out in general; much further than your radar will probably pick them up, if you even have radar. Good idea to get their course and speed and od a little plot on the old plottingor manoeuvering board to get the big picture.
The last thing you want to be caught doing is having to conserve your batteries and have a crew member say, "do you hear that?", turn the radio on and say, "is anybody ot there?", only to hear some mate on watch start to answer you while you're also hearing him say, "Hard Right!". Listen always, broadcast as much as you can within reason.
Just within the last year we had a story posted here on sailnet about a poor fellow who'd spent years restoring an old wooden classic only to be nailed by a tug and barge in the C&D canal in fog. He and his daughters barely escaped with their lives, one being submerged for quite some time within the now hulk. Somebody can probably find the post.
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