SailNet Community

SailNet Community (
-   Seamanship & Navigation (
-   -   Signalling (

sailaway21 03-17-2007 05:49 PM

Another thread got me thinking about signalling. With the wide spread use of the VHF radio, this topic tends to get short shrift these days. After watching "The Perfect Storm" last night, and watching their SSB antenna carry away, I thought I'd post some thoughts.

Most yachts, after their VHF is kaput, are reduced to waving their arms. This is probably not the most effective form of communication available. Sound and light signals have long been used for this purpose. In fact, under the COLREGS, the use of the VHF does not relieve a vessel of sounding required signals. I'm not going to discuss flag signals as they are not practicable on most yachts. But, if you've got a suit of 'em, and more importantly need them, they are certainly effective.

The incident that brought proper signalling home to me was one involving professional mariners exclusively. I was Chief Mate in a vessel anchored off Little Creek, Virginia. We were shaping up for the shipyard and had previously off-loaded our cargo of military supplies with the exception of 1,500 tons of ammunition forward in No. 1 hold and 20,000 tons of JP-5 fuel carried in the double bottoms. We were awaiting a berth at Craney Island to off-load the fuel. I had just lain down in my bunk when I heard the danger signal being sounded on the ship's whistle. "Whistle" is probably a misnomer as it is an air-powered horn that can be heard for miles. I could hear it plenty well from my bunk, one deck below the bridge deck. I went running up to the bridge in my shorts to confront a beautiful moonlit night, virtual unlimited visibility, and the spectre of an SL-7 container ship(owned by the Navy but manned with merchant marine officers and crew)at a distance fo approximately a mile and on a course that would either collide with our bows, or pass close aboard and fouling our anchor rode. The Third Mate, on anchor watch, had been attempting to reach them for some time on the VHF radio. I immediately called the engine room and told them to get an engine on line, at which point the Captain arrived on the bridge. The Third Mate was dispatched to the bows to tend the anchor while I continued to attempt VHF contact. The Captain sounded the danger signal a number of times on the ship's whistle. There was no response and the vessel continued on what appeared a collision course. The Captain instructed the Third Mate to veer the chain. The Third Mate (an acomplished sailor) was green and proceeded to drop the starboard anchor. We now had 5 shots out on the port anchor and the starboard at short scope; a more effective fixing the vessel to her position could not be imagined! I would add that we were displaying the required anchor lights as well as deck illumination required by the COLREGs. The SL-7 never did respond and failed to clear our bow, stoving in about 15 foot of it. Fifty feet further aft and I might not be writing today. I vaguely recall remembering my Dutch mother's instructions on the wearing of clean underwear, although I didn't think it would have been of much consolation to either of us had things turned out differently!

At the Board of Inquiry the pilot was dismissed with no charges as he is held to be only an advisor to the Captain. The Captain of the SL-7's defense amazingly centered around our use of the danger signal. A careful reading of the COLREGs/Inland Rules reveals that the danger signal, five short blasts of approximately 1 second each, is used only when underway. This was sufficient to result in a "warning" being placed in the Master's file and no other action. Had the "allision" resulted in more serious consequences I doubt he would have gotten off so lightly.

The appropriate signal to have sounded would have been "Uniform". "U", in Morse Code, is two short followed by one long, and signifies, "You are standing in to danger". Lima or X-Ray could also have been reasonably used in the circumstance described.

The point to this long thread is that signalling is little understood, even, on occasion, by professionals. Nevertheless, it may be your only form of communication in a dire situation. Dire situations are not the time to be learning signals or acquainting one's self with their sending. The most obvious methods of signalling available to the yachtsman are sound and light. This is actually much easier than might be thought, you probably already have the gear on board. A compressed air horn, with spare cartridges, is sufficient for sound signalling. It should be borne in mind that the COLREGs desire a minimum of manoeuvering sound signals in restricted visibility so as to avoid confusion. Of course, this does not include the required signals sounded in restricted visibility. Restricted visibility is not fog only and the requirements do not end if you are out of the area of restriction but still near it. Light signalling can be accomplished with a large lens diametered flashlight. It will prove unsuitable, in most instances, for daylight signalling, unlike the signal/searchlights found on Navy and merchant ships. For night-time signalling it is excellent as it can be pointed in the direction desired. It should never be pointed toward the pilothouse of any vessel as a searchlight in an attempt to attract attention. This is against the regulations, although I have seen references to doing it in sailing magazines by those who should know better. You may wish to attract attention, but the attention you attract may be useless if you have destroyed the night vision of the attractee! Shine it up on your sail and flash it on and off. An item I strongly recommend, which is usually only carried by Naval vessels, is a colored lens for your signal light. Red works well, but can be confused with other lights. Amber is an excellent color or a version of orange. Colored plexiglass works for this and you can just tape it to the light without having to re-engineer your large flashlight. The purpose of this is for more effective signalling. You can attract another vessel's attention with a flashing white signal light, but it is difficult to read code off a white light at sea in the dark. You have to send your signal much more slowly or the glare will confuse the dots from the dashes. The amber color maintains visibility and is distinguishable and distinct in it's unique color.

The single letter signals, as well as multiple letter/number signals, and their method of transmission are found in the "International Code of Signals". Mine is a 1969 edition known as h.o. 102. I am sure it is still published, probably with the same 102 number, by whatever the latest name the old DMAHC is operating under today. It is a thin volume, 8x11 and 3/4 inch thick, and covers most all of which one needs for signalling, including radio procedures. Laminated cheat sheets are readily available but not a real substitute for the book. Mastery of morse code, while desirable in a perfect world, is not required and included in the book. I believe having the book, and a familiarity with it's contents, is sufficient for the sailor. Those moored in an anchorage with like minded sailors can become quite proficient over the course of a few evenings spent signalling each other across the water. Those more fanatical may be intirgued by the semaphore signalling instructions contained therein. Navy signalmen communicate, while alongside another vessel, by semaphore, without the flags, such important details as what kind of Captain they have, the quality of food, and the possibilities for sexual congress in the next port-all without anyone else, other than another signalman, knowing what they are saying.

As with navigation, there were ways that things were done before everything became possible with a $199 black box, and sometimes it is desirable to have a familiarity with those methods. When they become necessary to use it is usually an inappropriate time to learn them or wish the proper equipment was available. Alpha Romeo

sailingdog 03-17-2007 07:11 PM

Good post...

Tartan34C 03-17-2007 10:05 PM

I have two sets of signal flags. One is a yachting set and it is for dressing ship and the other is a commercial set and the letter flags in that set are 3 feet square and itís for actual use.
All the best,
Robert Gainer

Valiente 03-17-2007 10:35 PM

Good post. I last used sound signals on Nov. 12/06, when we entered Toronto Harbour to fuel up for winter layup. The visibility was about fifty feet in the fog, and I had my wife at the bow on lookout for the buoys and I was at the poop deck wheel giving the five short blasts. At that time of year, the only real danger was the ferries to the Island, but as Toronto Harbour is frequently jammed with everything from tall ships to canoes and Zodiacs, they are on their game. I kept a VHF "watch" on ch. 13 and 16 and, prior to leaving, plotted my turns via the harbour buoys using a paper chart and standard compass bearings, plus keeping a constant speed of 4 knots so I could figure out roughly the intervals between buoys/course changes.

It was hardly a major feat of navigational excellence, particularly as I could frequently see the shore, more or less, but we found the fuel dock on the Island without incident, and got back to our own club in a similarly uneventful manner. Other than finding a harbour entrance during a power blackout (the buoys were working, but the red and green on the seawall weren't!), that is about as complex as it gets on Lake Ontario...

The only thing of note that happened was I heard a ferry captain on 13 telling his counterpart that "some guy's out there in a yacht giving five don't get that much around here". Presumably they had us on radar as I don't recall seeing or hearing a ferry, despite crossing their lanes.

sailaway21 03-19-2007 11:48 PM

While I commend you for sounding signals, I would refer you to Rule 15 of the COLREGs. If power driven, a prolonged blast every two min. international, every one min. inland. A sailing vessel, one blast on stbd tack, two blasts on port, and three with the wind abaft the beam, int. and inland. But you got their attention, arrived safely, and that's the point isn't it. <G>

Valiente 03-19-2007 11:59 PM

I was motorsailing and the situation was a little equivocal, but I concede the point <G>.

nightowle 03-21-2007 02:34 AM

I sail on Puget Sound in Seattle....does that fall under International rules or as an inland waterway?

sailingdog 03-21-2007 06:29 AM


It depends... but if you look at the local charts... it should have a dashed line, usually purple IIRC, that shows the boundary between the two, and which rules apply where.

btrayfors 03-21-2007 08:20 AM


Nice post. Good story, too :-)

The Colregs may have changed since your incident.

I believe under the current Rules an anchored vessel may, indeed, give the danger/doubt signal (5 or more short blasts), under Rule 34. The course guide I am presently using to renew my license specifically says that an anchored vessel may sound the danger/doubt signal, as well as vessels underway in meeting, crossing or overtaking situations.

In restricted visibility conditions an anchored vessel sounds the normal 5-sec rapid ringing of the bell every minute and, if over 100 meters long, in addition sounds a gong rapidly for 5 seconds after ringing the bell. Optionally, all anchored vessels may also sound a whistle signal, Morse "R", one short, one prolonged, one warn other vessels.

Not sure about the "U" signal. Can't find it in the current regs.


sidiag 03-21-2007 08:58 AM

For those who might be interested,

International Code of Signals - HO 102 is

available here ->

as a free download.

You might also try
Flags is a freeware program written to teach the International Code of Signals flags.

Good Day!

All times are GMT -4. The time now is 07:31 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging v3.1.0 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
(c) LLC 2000-2012

For the best viewing experience please update your browser to Google Chrome