Small Craft Traffic Avoidance

I had a close call with a recreational boater on the Ohio River a while back that has stayed with me to this day. They inexplicably pulled out in front of my 4 barge tow at the last minute, I’m sure the guy didn’t even realize I was approaching.

After this and other close calls, I came to one conclusion. I treat all rec boaters the same: I assume they are all shitfaced drunk or have absolutely no idea what they are doing. This way I try and give my self a wide margin of error and assume they will act erracticly.

I found not all of what looks like drunks is actually that. I was headed upstream past midnight up a deep and wide river. Despite being deep and wide, it is still a bit of a challenge because the shore is pitch dark and the winding riving is full of unlit marks. I am the only thing moving and then comes a powerboat looking to be about 50-60 feet long headed my way. They -for once! - actually have all their running lights working, but also have various color LED lights on the boat and the bridge. It actually was hard to get a good perspective with all the weird color lights. It did look like CBDR, so even though I was stand on I changed course. Soon enough CBDR again. Change course again and now he is shining his spotlight on me, blinding me, and back to CBDR AGAIN!!!
I shined my light on him and gave a pretty nasty sounding call on the radio. The powerboat spotlight captain explained he was nervous about hitting something, saw my lights high up (60 feet) and figured I had to be in the best part of the river and was going to aim for wherever I was. After I settled down I explained what he was doing was confusing and dangerous and gave him some advice about a good course to steer and what he would see next.

Prepare for the worst and hope for the best. Good watchstanding practice.


Re the described situation: The COLREGS solution is to maintain course. Your example doesn’t describe the wx or time. Is it daylight or night? Is the wind force 3 or force 6+? If it’s a 3 in daylight, I’m good at 1 cable CPA. If it’s a 6+ or night, the other guy might not see me, and I’ll call him up and ask him to alter course to stbd and pass clear.

A course alteration to port is 99.9999999999 percent of the time NEVER-EVER is a good thing.

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I read this with interest as I am looking at it the other way round as in big ship avoidance. My experience of many crossings over the Dover Straits in a small yacht is that one has to get very close before you can actually see if you are going to pass ahead or behind a ship. I imagine from the bridge it must look very uncomfortably close.

The books tell you to take a bearing on an approaching ship. But in reality it is almost impossible. A small yacht is pitching up and down a good yard and yawing through 20 degrees all the time. One is lucky to get an HBC to within 10 degrees… that’s far more than the change needed to confirm a crossing ahead or aft of the ship.

I tend to stand on until I can see the details on the ship and can see the transits on deck fittings moving or changing… Then if needs be I will tack to a totally different heading to make my intentions clear. That is assuming someone on the bridge has seen me and is taking an interest.

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Maybe that is because they fly at 450 knots…:wink:

Please note I said on the horizon. That would put an aircraft below ten thousand feet and therefore restricted to an IAS under 250 kts. :slightly_smiling_face:

The book should be changed to say that an AIS should be used in this case.

The discrepancy here between the vessels in size, speed, maneuverability and tools available are at or beyond what the COLREGS is capable of resolving.

Here is a COLREG conundrum from the small guy looking up: (pre AIS days)

  1. I am under sail at night.
  2. I see lights of a freighter come into view. Between the aspect of the lights and a few bearing checks, it looks pretty close.
  3. We have a good wind aft of the beam. My speed is probably varying between 6 and 10 knots and we are yawing through probably 20 degrees. This makes resolving a bearing somewhat inaccurate.
  4. At the usual closing speeds, there is not a huge amount of time to make a decision.
    I am definitely stand-on per the COLREGS. There is no channel, the water is a mile deep, no one is minesweeping, no one not under command, no restricted ability, etc etc.
  5. If they see me, which I do not know, they see one light, red, green or white or maybe the color changes as I surf the waves if they are near the dividing line.
  6. ARPA/MARPA has one hell of a time trying to lock onto a sailboat in waves and also from one, odds are they have no good fix on us that way nor us them if we even have it.
    So what to do? The rules say just keep going and they will go around me.
    If I follow the rules and they don’t change course, we might have to do a crash tack or gybe. Even worse, whatever way we go to take evasive action they might also go. It takes them a long time to change course compared to us. If we are close they might not even see us anymore.
    My standing orders were to assume the ship would not change course unless we could verify it on the VHF or it was really obvious. If those two conditions were not met, we would ourselves make an obvious course change.
    That brings up the final issue for the ship, they probably get a random assortment of boats that stand on when they should vs. Monty Python tactics (run away run away) and maybe grow tired of going around boats that turn anyway.

AIS is SO nice to have now :smiley:

In the example there’s good visibility, daylight, and neither draft nor other traffic is a factor. I’m eyeballing the situation on a 90s prosumer raster scan unit, and you’ve just started coming off the ERBL, so the cable of CPA is a rough guesstimate. With your gyro referenced radar and stable heading, you probably see exactly what is going on, and you may be comfortable with a one cable CPA, but I don’t know any of that. All I know is that our courses converge somewhere up ahead, it’s going to be relatively close, and I’d be considering the situation carefully if I was in your shoes.

Of course, a degree or two to starboard would resolve this nicely with no need to communicate, but I’m trying to construe an ambiguous yet undramatic case here, so I’ve got some pressing need not to come to starboard (I’ll give you a reason if you need it).

I don’t see the big problem with altering to port here. If I can’t raise you on VHF, I’ll make an obvious course change (say 40 degrees) that triples the CPA, and I’ll be across your head line long before you run out of room to act if something bad happens. The question was: Would you want to talk about it, or just have me sort it out without bothering you?

Re the degree or two course change:
IIRC that is what the Andrea Doria did with sub-optimal results.

For me a one cable CPA is too close in most circumstances.

So I’d like confirmation that you can see the ship. For example if I can see that you are turned around watching the ship.

Also in this case COLREGS require you to maintain course and speed. If for some reason that can’t be done a VHF call would be appropriate.

As far as the watch officer being annoyed/not annoyed I would disregard that. In my experience the ones that are annoyed are the ones that don’t understand the situation.


I’ve had many conversations with sailing vessel’s on VHF in open ocean and not so perfect weather conditions imploring them to get a bright spotlight they can shine on their sail as an added indicator to their presence. A single red light on 12v power is very difficult to make out visually at night in a bad weather situation.

I also believe that parabolic radar reflectors mounted high on the mast of a sailing vessel are worth their weight in gold coupled with an AIS.

We are up there looking for you, but certain conditions require a mechanical advantage. And please don’t hesitate to use the VHF to at least announce your presence. Every little bit helps.


For the most part, since I was not a “VHF” guy; you know “the radio assisted collision” stuff, make an obvious course change in ample time, and the situation goes away. Just do it. If I have doubt about what you’ve done, I’ll call you!!!

The context is not the same. In practice small changes are sometimes useful.

For example in heavy traffic, ship on the stbd side crossing from stbd to port. Own ship makes a substantial course change to stbd showing the other ship open range lights and a red light and which will result in passing astern with a 2 mile CPA which will show as a good vector on the ARPA.

However there is other traffic about, not room for a big CPA so once own ship is abaft the beam of the other ship start cutting in little by little to port. Don’t scare them with an obvious maneuver. Always keep steering astern of them. Pass astern at 1/2 cable or whatever.

The whole time showing them a red light and a good vector astern on the ARPA.

Also the optional “sailing vessel lights”: RED OVER GREEN, SAILING MACHINE!!

And what is about ships that they are nowhere to be seen until you are about to enter the VTSS… The five come barreling along so that one of them will be right on top of you as you are crossing the VTSS… but once you clear the VTSS…they all disappear?

Happens every time I cross the Dover Straits.

Even though I work on a big boat, on my time off I frequently sail a little boat. Madness according to some of my colleagues.
Regardless of which I am on presume the watch keeping on the other is a incompetent or drunken fool until action proves otherwise and I am pleasantly surprised.
I have my limits, if no action is seen, I take the action required.,

As for ARPA. Even a relatively small sailing vessel with a simple radar reflector can be picked up well enough in most circumstances for an ARPA to effectively track the vessel. If the radar is appropriately set for the prevailing conditions. Basic watch keeping.

Heavy rain and rough seas will certainly make detection and tracking of small vessels more difficult. Even so particularly S band Radar is very good at picking up small vessels.
Odds a good you are being tracked in most circumstances.
But remember my first presumption should still apply. It’s better to be pleasantly surprised.

I always carry a HBC on my sail boat JIK I have the sudden urge to take a bearing as per the col regs. I don’t have AIS, I just eye ball it most of the time. Even though my little boat is bouncing about and going in approximately a straight line at a steadyish speed.
I can tell if a vessel is steady by watching the back ground. If there is any, or by comparing its relative bearing just visually. Compared to fittings on boat or just the horizon from my position. Not quite kosher but it works. Well enough for hand grenades or horse shoes.

If it looks like it’s getting bigger quickly, in roughly the same point or O’clock, it’s coming close.
If they take action it should be apparent.
If not and it keeps getting bigger and you become concerned.
Take your own action.

It’s been a long long time since I crossed the channel or transited up and down.
Self preservation, don’t impede, if the big boat is give way and you are stand on. If in doubt Don’t turn to words it, turn away, put him behind you. After he is past go back to your course.
If you are sailing they are mostly give way and you are mostly stand on.

Remember don’t impede. It’s better to take action early and avoid getting into a close quarters situation in the first place.
Much less stressful.

I have read else where about ships being spotted on AIS making small alterations many miles away to avoid small vessels. Maybe some do.

I don’t. any newbie who does will get my boot six lace holes deep.
If I alter for you, I will make it obvious. I will show you my other side light.

When in a busy traffic lane, I often made small alterations to jockey for position with other ships. Not for the small vessels.
Most I would leave until closer then make a more obviously seen alteration. I could do this because I intentionally kept my distance from other big vessels.

What they do in the Chanel today I can’t say. I don’t work there and haven’t for many many years.

Today my tolerances may be very different to some others. I may tolerate much less CPA than some other vessels. Depending upon the circumstances.
In some circumstances I pass other ships with a CPA on 1 cable. (Narrow Channel)
Open water out of the question even with a small vessel.
My vessel is very highly maneuverable. What I may tolerate other less manoeuvrable vessels may not.
I encourage use of the throttle. It’s use routinely expected.

Many deep sea ships the throttle is a big deal.


The perception about what constitutes an adequate CPA between large and small craft can be subjective. I was a young flight instructor when an airline pilot who hadn’t flown in a small plane in ages was sent to me for a check ride. He wanted to qualify to rent a single engine aircraft at our FBO so he could to take up his latest female conquest on a dare and take her for a private flight.
I was familiar with the heavy volume at Santa Monica airport and the tower’s CPA expectations to keep traffic moving but this guy kept yammering at me that we were getting much too close to other airplanes in the pattern. He got on my nerves to the point where I landed the airplane and I ended the session.
In his world of standard separation for airliners, he was right, we were much too close.
In my world, it was just SOP and we were perfectly all right.

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So you probably missed out on the “flare at 50 feet” entertainment. That would have been the next thing, 49 feet is WAY too close to the runway!