Near miss, AIS in the Malacca Straits

Valhalla Nearmiss3

Go to this page to see a series of screen grabs illustrating a scary close call between the 32’ ketch Valhalla and the 132 meter tanker Miri Cahaya. I’d almost guess that the tanker was trying to slow down and turn right to go astern of the ketch, but that’s easy to say sitting in the comfort of my office. Captain Sargent was looking at a whole lot of moving steel with a Closest Point of Approach at one point of 44 meters! He also had prior knowledge of some malicious mariners in these waters, which is probably why he was collecting a history of screen shots. At any rate, he made a possibly controversial last minute decision to turn hard left and cross the tanker’s bow, and it worked. You might also look here to see Valhalla’s AIS setup, which includes a NASA receiver and SOB software (note above how it gives time of last message; nice!). The page also has some screens showing how AIS busy the Malacca Straits are. I understand that the Singapore Vessel Traffic Information System is possibly the busiest in the world, and is using AIS messaging heavily to route ships.

This entry is also an example of how the Internet is changing cruising (and all communications). This incident happened on 11/17, was posted to Valhalla’s site yesterday, and Panbo reader Steve Tripp emailed me about it today. And as I was writing the entry this morning, Captain Sargent—now located in Langkawi, Malaysia—updated this useful page of cruising info about Port Carmen, Philippines, including an antique chart scan improved with GPS annotations by Steve. Big planet, small world.

Ben Ellison

Ben Ellison

Panbo editor, publisher & chief bottlewasher from 4/2005 until 8/2018, and now pleased to have Ben Stein as a very able publisher, webmaster, and editing colleague. Please don't regard him as an "expert"; he's getting quite old and thinks that "fadiddling fumble-putz" is a more accurate description.

25 Responses

  1. John says:

    For several reasons.

  2. Anonymous says:

    Without an AIS on board to tell what the other ship was doing would it have been possible to detect his turn in time to take evasive action?
    Also, imagine this same situation in fog…

  3. Dave says:

    He mentions the SOB software & says “CMAP NT/PC charts, which are rather expensive”. I looked into this, and the local dealer wants US$2000 for charts to cover peninsular Malaysia. I can go & buy paper charts for $20, and I was shocked that they wanted US$2000 for the electronic version. Are electronic charts REALLY this expensive or was the local dealer trying something on or mistaken? I can’t imagine small boat owners being willing to fork out US$2000 for some charts.

  4. Andrew says:

    Unrelated to the technology, but is a 32′ sloop ever the ‘privileged vessel’ when a commercial tanker is involved?

  5. Ben Ellison Ben Ellison says:

    Dave, There’s definitely some confusion about C-Map pricing; that’s way too high. I’m looking for exact prices on cards and CD charts for that area and will include in a coming entry.

  6. Anonymous says:

    If there was no fog what benefit did AIS provide in this instance? Also I have always felt that ‘might makes right’ when in a situation with a large commercial vessel or even a large private one for that matter. This might be a case of one believing that technology can overcome simple good judgement.

  7. Anonymous says:

    AIS provided information about the ships movement that may not have been detected by ‘eye’. It also provided the ships call sign, even though they didn’t respond to the calls.
    I’m no sailor so Ben should correct me, but it would make sense to me if the more agile boat was supposed to get out of the way of the slow moving tanker.

  8. Ben Ellison Ben Ellison says:

    Oy…tricky subject. The navigation rules treat a big ship and a little boat the same as long as both are under command and under power, unless the ship is navigating a narrow channel. In the real world, however, the little guys tend to stay out of the way of big guys. In this case, even with all the AIS screens, it’s hard to tell exactly what happened and why. For Valhalla, the important factors are that the ship appeared to turn right toward them and did not respond to radio calls.

  9. Dave says:

    This is a situation that the skipper of the ketch should never have left happen. After the first determination that a collision was possible , he should have bore off to starboard, increased speed and opened the gap , run into shallow water if forced, just get out of the way early and fast, Other wise your grave
    stone will read, “COLREGS stand-on vessel”

  10. Steve says:

    Bellingham sells the C203 cartridge for the Malacca Straits at about $219, but you need special equipment or a plotter to use it. Licensing the CD is different I’m sure.

  11. Ben Ellison Ben Ellison says:

    To Dave #2 I say that none of us are in a position to judge Valhalla’s actions accurately or fairly.

  12. Terry says:

    I have just found this blog and appreciate ALL of the comments about that ‘near miss’ situation I encountered. In retrospect I am now of the opinion the helm on the tanker was attempting to pass my stern but two factors were over riding my thoughts: #1 IF that was his intention he should have made an initial turn that was obvious, by eye, to the observer, me. #2 My subconcious thoughts about the two recent collisions between yachts and ships exacerbated the visual scene of an intentional ramming.
    I have also added some observations about using AIS with two programs at
    I welcome comments directly to me at [email protected] (without attachments please).

  13. Terry says:

    This is the COLREGS rule to which I referred in #1 of my previous posting.
    Rule 8
    Action to Avoid Collision
    (a)Any action taken to avoid collision shall, if the circumstances of the case admit, be positive, made in ample time and with due regard to the observance of good seamanship.
    (b) Any alteration of course and/or speed to avoid collision shall, if the circumstances of the case admit be large enough to be readily apparent to another vessel observing visually or by radar;
    a succession of small alterations of course and/or speed shall be avoided.
    A quick link to the COLREGS is at

  14. Terry says:

    Have found (in my opinion) an excellent AIS display program, called Yacht-AIS.
    Have added an update about it to

  15. Anonymous says:

    First of all the key to maneuvering is to turn your perspective around and look through the other guys eyes. If he is looking at one small boat he may just go make coffee. If he is looking at a fishing fleet he will probably go around.
    Second if there is ANY possiblility of collision a few things should be done, but the first is to take EARLY and SUBSTANTIAL action that the other guy can see and react to.
    Third when two vessels are meeting at a turn if you are plotting on radar the true vectors should be streched out to allow prediction of who will arrive at the turn first. You can then guess what the other guy will do, you can’t totally rely on it but its a hint.
    Fourth an experienced mariner “knows (feels)” when the give way vessel is not going to do what is required. IN that case regardless of what the rules say you must act early. Here the stand on vessel could turn LEFT and AIM for the other ship. That tell him if he is watching, or if he later sees you, you are planning to pass astern of him. It also leaves you time to turn around 180 if he turns right. And if he does turn right because you have only turned left to the point where he is dead ahead you are not totally committed to go left more and more. In otherword s you have prevented a waltzing situation.
    Remember when looking at ships and expecting them to take action:
    1. the mate on watch may be figuring out a sight in the chart room.
    2. the captain may have just left the bridge and told the mate “I’ve been up all night and am going to get a nap, but call me if you have to change course” I can guarantee if the Captain is a tyrant a mate will hold on until the last minute hoping the other guy will do something.
    3. there are a million other reasons that the tanker might not see you.
    4. the turning characteristics of the ship may be such that it won’t turn tight enough to do the job.
    5. the stability of a ship may be such that a tight turn will lay the ship over too far. Passenger ships sometimes have this problem and the little old ladies fall down.

  16. Terry says:

    I appreciate the comments by ? posted January 4, 2006 10:04 PM.
    The ‘fourth’ comment is exactly what I did so I’m glad to get some confirmation that I did the right thing in this commenter’s opinion.
    And his ‘#4’ may have been the reason the tanker did not comply with COLREGS Rule 8 (“large enough to be readily apparent”) but it that’s the case he needs some attention to the steering machinery!
    Also, I have not yet explained that I was sailing hard on the wind on a starboard tack and a turn to port away from the wind (and to go behind the other vessel) was quicker than tacking, which would take about 30 seconds more to release a boom vang/preventer that was set to trim the mainsail.
    Safe sailing in the new year.

  17. Terry says:

    Have put another experience using AIS on Valhalla’s Mooring Page at gemini/gemini.htm

  18. Terry says:

    I attempted to alert folks to a nice update about the Yacht-AIS program but it was denied ‘for questionable comment’.
    Oh well, I tried!

  19. Terry says:

    My posting was denied because I had used a series of periods to separate some words. Here’s the corrected version:
    The Yacht-AIS Pro program has just been updated with
    some new features. These are described in an update
    The Y-tronic folks are very receptive to suggestions
    for improvement from users. Very refreshing!

  20. Terry says:

    I did a ‘line of sight’ evaluation of my AIS installation. See the latest update(20 Jan)at:

  21. Bruce says:

    Well, I have stumbled onto this blog page by accident, as we are currently travelliing through the Melaka Straits. I have not read all the comments but I am concerned by some comments regarding the IRPCS and the rights of vessels. “might has right of way” is a silly and dangerous statement spread amongst small boaters with little if any knowledge of the rules. The rules clearly state the action to be taken by vessels and if involved in an incident you will be held to account under international maritime law. It is hard enough for ships to navigate safely around the increasing number of recreational voyagers. We do not need them to be second guessing, what our next move might be, due to the confusion caused by a few uneducated boaters, dodging ships willy nilly, because their scared, due to their lack of knowledge of the rules. If your not sure, it’s easy to keep out of close quarters situations with ships, stay at home.

  22. Dave Wilson says:

    Bruce, it will no doubt be easy for you to litigate from the bottom of the ocean. Not every captain of a commercial vessel gives a hoot about us. My experience is that many of them don’t even maintain a proper watch.
    s/v Whisper

  23. Anonymous says:

    I concur,
    I have had the opportunity to talk at leisure with a few tugboat captains a freighter captain. I took it as an opportunity to get their input on how to minimize stress for both the tug/freighter and the cruising sail boat. The response was loud and clear, BBR (Bigger Boat Rules). Stay clear be safe.
    Perhaps the story is different in other parts of the word.

  24. Terry says:

    I asked Jim Austin, who did the Rules of the Road series for Ocean Navigator Newsletters, to look at my original posting and tell me what he thought.
    “Here’s my take
    Starting with the premise that its always easier in a comfortable chair at home than dealing with the situation as it happens…given that, will offer a couple of thoughts.
    Within the past year or so there’s been increasing concern about use of VHF for collision avoidance – particularly at short range. Both Singapore and British organizations have warned of the trap it sets “when the time has come for action…” Identifying who is talking with who, the delay in taking action it induces and language barriers are some of the points that have been raised.
    As a general principle, a turn to port shoud be avoided like the plague unless in-extremis exists and that is the only way out….and it certainly seemed like that developed.
    So – then how to keep out of it in the first place? I may have missed it but was a short blast given by either? If a collision had occurred, a maritime court would lave looked for that and the danger signal as well. Granted, the “squeek” by a hand held probably not heard but ………!!!!! Good to remember that these were International waters so the blast would have been a rudder signal – not simply intent.
    Speeds were roughly the same, so an early turn to stb’d (and completing a 360 if necessary) would have let the other guy know of the small-boy’s intent. He may have been slowing to let you pass ahead, given the pretty good southeast set.
    A turn to stb’d would at worst created a parallel (or near-parallel) collision at nearly zero relative speed, The port turn, on the other hand, risking a head-on meeting.
    When mentally rollerdexing as to what-in-hell-do-I-do-now, a pretty reliable guide is to take “early action” when you start to doubt or question the other guy’s intent.
    One judge a long time ago made the point that in taking early action, it gives vessels time to unravel the situation (paraphrased, sorta…)
    All in all….nice job of dodging the heavy metal.
    Incidentally – a TOTALLY unrelated issue is the use of AIS in pirate-prone waters (the Straits, African Horn, etc.) Sort of a “here-I-am, here’s my c/s…etc, come and get me !!!!!!!!

  25. Have received some comments from a reader who gave permission for me to post. He makes an excellent point about vessels constrained by draft which I had not considered. Must remember in the future to look for the day shapes … something that is easy to overlook during the emotional intensity of a close encounter!
    I�m master of a large very modern chemical tanker � and frequently pass through the straits. I noticed that your screen grabs did not show depths. Ive plotted the positions for your rogue tanker, and they pass over an area of marginal underkeel clearance � with hazardous depths both to port and starboard as it crossed the bank. An alteration to stbd would have been seriously affected by a 5m patch. You didn�t say whether you looked to see if he was showing the cylinder required for a vessel constrained by its draught � which this vessel almost certainly was (A vessel of this size would have been drawing between 5m and 8m. If this was the case you were certainly required to take early and substantial action to provide sufficient searoom for his safe passage � he was also required to comply with the crossing regulation when it became apparent that you had taken no action and risk of collision now existed. The stand on clause does not mean �stand on regardless� ! as soon as you were in doubt as to his intentions it was somewhat foolhardy to try and communicate by VHF � this is fraught with danger � you should have shown him your stern. His track, seems to come to stbd into the channel, which is what would have been expected � he certainly couldn�t have taken a turn with shallows close by. Your action in altering to port is specifically precluded under the colregs, and in the event of a ding you would doubtless have been considered partially to blame. The other vessels slow speed would have precluded sudden manoeuvres, and even if he had a bow thruster it would not have been effective at that speed. The correct action on his part would have been to have stopped. As someone pointed out on your site � the narrow channel rule didn�t apply � however � the constrained by draught paragraph almost certainly did.!! An overriding factor in the collision regs is quite simply �the observance of good seamanship� I wonder if you had actually considered the constraints placed upon the other vessel � in my experience few people do.
    Thanks for posting it though � it gave a lot of people something to think about � and certainly attracted a good few �interesting� responses !!
    I wish you a successful and safe new year � and happy sailing !!
    Very best regards
    Captain Trevor Northage MNI

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