how can Colregs rule 5 - lookout - be met by solo sailors on long trips?

What do you base the assumption on that he had sufficient sleep the previous 24 hours?
Maybe he had taken sturgeon?


Yup, it doesn't take too much imagination to think of many, many ways he could have become exhausted in a literal sense and that's before considering exhausted as a euphemism for other states.

I've started sails exhausted, I've become exhausted sailing from Cowes to the Needles, I've become exhausted in a single 40 minute dinghy race. I've developed man flu during a sail. I've certainly been sea sick or 'exhausted as a newt'. On the other hand as a teenager I used to get up Friday morning, do a normal day and then mainsheet trim overnight all the way to France and arrive Saturday morning with plenty left in the tank. I'd look around at the shattered 40-somethings around me completely uncomprehending of why they were knackered. (See also night vision.) Was there something wrong with them, I wondered? I know now. :(
 
I have had to dissuade a newcomer to sailing who had just bought a westerly in essex from setting off end of november to deliver against the prevailing winds to the solent. He had no real plan for stops and would 'do it in one hit'. Luckily he didnt do it as i imagine a similar outcome.

There must be a back story to this report.

Edit. As it reminds me a few years ago of a man who bought a 21 foot bilge keeler from the yard at rice and coles in burnham and set off to bring it to leigh where he would be keeping it.
He turned right as soon as the land started disappearing on the crouch on a falling tide and promptly ran aground and was picked up by the lifeboat on the next tide and they towed him back to rice and coles. He had no idea there were mudbanks out to the whittaker, had no charts and only a tiny outboard with a small tin of petrol.
 
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The longstanding debate about whether a solo sailor can realistically comply with Rule 5 is becoming increasingly moot. When this rule was drafted, the only practicable means of maintaining a lookout were the human eye, human hearing, and very limited electronic aids. The modern maritime environment, however, has evolved dramatically, and so have the tools now “available” to both professional and recreational mariners.

Autonomous and remotely supervised vessels, including Maritime Autonomous Surface Ships (MASS) and uncrewed surface vessels, routinely employ advanced perception systems such as computer‑vision object detection, automated radar/ARPA target classification, AIS anomaly detection, and multi‑sensor fusion for collision‑avoidance decision‑making. Although such vessels are often nominally described as having a “watchkeeper,” the human’s role is supervisory: the actual detection of other vessels and hazards is performed by AI‑enhanced systems. The increasing acceptance of these technologies by industry and international regulators demonstrates that AI‑based detection is already viewed as a practical means of fulfilling the lookout function required by Rule 5.

These same capabilities, once limited to defence research and commercial shipping, are now widely available to ordinary yachtsmen in off‑the‑shelf equipment. Examples include AI‑enhanced radar plotters (from Raymarine, Garmin, Furuno and others) that automatically classify targets and highlight non‑AIS contacts; computer‑vision lookout systems mounted at the masthead that detect floating objects, unlit boats, and navigation marks; and AI‑supported autopilots capable of real‑time obstacle awareness using fused sensor inputs. These systems are explicitly marketed as watchkeeping aids and are already common on modern leisure craft. Their operation fits squarely within the meaning of “all available means” as used in Rule 5.

Importantly, Rule 5 is technologically ambivalent. It does not specify who or what must perform the lookout function; it specifies the effect: that a proper lookout must be kept using all appropriate means. If commercial operators, including autonomous ship programmes, demonstrate that automated systems can fulfil the perceptual component of lookout duties, then these systems, when available on leisure craft, must logically be considered part of the “available means” for the recreational mariner as well.

For the solo sailor, this development is especially significant. Periods of controlled rest are a practical necessity during extended passages. Such rest does not represent negligence; rather, it allows the sailor to remain effective, alert, and capable of sound judgement. In many cases, a solo sailor taking short, structured rest intervals is more responsive to alerts from AI‑assisted lookout systems than a fatigued human watchkeeper in a hub (the watchkeeping equivalent of a call centre) monitoring multiple vessels and systems with no physical link to a vessel (when a proximity alarm sounds I am going to jump out of my bunk). A virtual watchkeeper, using radar, AIS, and computer vision, does not suffer from fatigue, darkness, distraction, or cognitive overload. When paired with auditory, visual, or vibration alarms, these systems can ensure that a resting solo sailor is alerted more reliably and more rapidly than would be possible using human sight and hearing alone.

In this sense, AI‑assisted lookout tools do not diminish or replace the human element: they enhance the solo sailor’s ability to detect hazards promptly, interpret risk correctly, and take early and decisive action. The evolution of marine technology therefore makes it not only possible, but in many respects easier for a solo sailor to comply with the spirit and operational intent of Rule 5 today than at any time in the past.
 
Importantly, Rule 5 is technologically ambivalent. It does not specify who or what must perform the lookout function; it specifies the effect

That’s a really sharp observation.

“Every vessel shall at all times maintain a proper look-out by sight and hearing as well as by all available means appropriate in the prevailing circumstances and conditions so as to make a full appraisal of the situation and of the risk of collision.”

Doesn't say it has to be a human and I doubt there's been a court case yet to decide if it does or not. My bet is it doesn't need to be a human.

Every day is a school day.
 
Possibly the area for debate is whether the tolerance of solo sailing can be justified as solo racing yachts get bigger and faster. Back in the early days, you were looking at 30-50ft yachts which were not likely to be going much more than 10kts. If anyone got hurt or killed in a collision it was likely to be the skipper. These days you might be talking about 100ft multihulls regularly going above 40 kts. That seems a different level of risk.. Offsetting that, electronic collision avoidance tech has improved massively, but you still cannot assume everyone has AIS, even offshore. If an accident happened and the skipper was asleep with nobody on watch, I imagine that a manslaughter conviction (corporate or individual) would be very easy to secure.
Not really - only about 10 years on from the start of solo long distance races the size had grown to higher than we have now - in 1976 there was a 72m entry from the cross Atlantic race.
 
The longstanding debate about whether a solo sailor can realistically comply with Rule 5 is becoming increasingly moot.
I’m not sure it is. The rest of your post then went on to describe the latest and greatest technology which might be able to assist a watchkeeper. But very few leisure boats, and even fewer who sail solo, are equipped with even a fraction of the technology you described. IF as you posit, the technology based lookouts can fulfil the rule then they only achieve that if they are actually in use and set up properly, but moreover they seem to diminish the argument that “traditional” solo sailing is OK if what we are saying is OK because of the tech aids. So IF technology makes it a moot point, it will only do so with the tech installed and working - the question of what is the minimum tech to make it acceptable will still apply. I am sure many solo sailors do it because they want to be disconnected from the world and minimise reliance on “tech”.
 
I’m not sure it is. The rest of your post then went on to describe the latest and greatest technology which might be able to assist a watchkeeper. But very few leisure boats, and even fewer who sail solo, are equipped with even a fraction of the technology you described. IF as you posit, the technology based lookouts can fulfil the rule then they only achieve that if they are actually in use and set up properly, but moreover they seem to diminish the argument that “traditional” solo sailing is OK if what we are saying is OK because of the tech aids. So IF technology makes it a moot point, it will only do so with the tech installed and working - the question of what is the minimum tech to make it acceptable will still apply. I am sure many solo sailors do it because they want to be disconnected from the world and minimise reliance on “tech”.
I think where he drifts into fantasy is talking about AI computer assisted systems but most solo sailors venturing offshore will have AIS and a goodly proportion of them will have a relatively modern radar equipped with MARPA and guard zone configuration a few will have night vision cameras and a few will have access to satellite derived AIS ( predict wind pro) that will show AIS targets to hundreds of miles away. The only danger is things floating in the surface and most human watchkeepers won't see them at night and vessels that a radar won't pick up ( rare) and or not transmitting AIS.
 
I think where he drifts into fantasy is talking about AI computer assisted systems but most solo sailors venturing offshore will have AIS and a goodly proportion of them will have a relatively modern radar equipped with MARPA and guard zone configuration a few will have night vision cameras and a few will have access to satellite derived AIS ( predict wind pro) that will show AIS targets to hundreds of miles away. The only danger is things floating in the surface and most human watchkeepers won't see them at night and vessels that a radar won't pick up ( rare) and or not transmitting AIS.

We're talking about colregs and the coll regs say sight and sound. I'm sure it's possible/better/easier to make relatively safe automated craft that don't monitor sight or sound but that don't meet rule 5.
 
jamie N — melatonin is interesting. It helps with sleep timing (telling your body "it's night now") but it doesn't really improve sleep quality, which is probably why you slept longer but didn't feel rested. The deep slow-wave sleep that actually restores you isn't something you can take a pill for — it has to happen naturally. It's the same reason caffeine is a trap on passage: it masks the tiredness without fixing the underlying deficit.

arc1 — 0100-0700 is about as perfectly wrong as you could design it. Right through the circadian trough and then ending just as your body is starting to wake up naturally. Is this one of your shifts?

That wind farm story is sobering. finestgreen, billskip makes the key point — Southampton to Shoreham is only about 50nm, but if the guy hadn't slept properly the night before departure, or the night before that, he could easily have been running on 30+ hours of accumulated wakefulness by the time he got into trouble. The research calls it "sleep loading" — what you bring to the passage matters as much as what happens during it. Most people focus on the watch system but forget that if you've been up since 5am provisioning and stressing about the weather, your clock started hours before you cast off.
 
jamie N — melatonin is interesting. It helps with sleep timing (telling your body "it's night now") but it doesn't really improve sleep quality, which is probably why you slept longer but didn't feel rested. The deep slow-wave sleep that actually restores you isn't something you can take a pill for — it has to happen naturally. It's the same reason caffeine is a trap on passage: it masks the tiredness without fixing the underlying deficit.

arc1 — 0100-0700 is about as perfectly wrong as you could design it. Right through the circadian trough and then ending just as your body is starting to wake up naturally. Is this one of your shifts?

That wind farm story is sobering. finestgreen, billskip makes the key point — Southampton to Shoreham is only about 50nm, but if the guy hadn't slept properly the night before departure, or the night before that, he could easily have been running on 30+ hours of accumulated wakefulness by the time he got into trouble. The research calls it "sleep loading" — what you bring to the passage matters as much as what happens during it. Most people focus on the watch system but forget that if you've been up since 5am provisioning and stressing about the weather, your clock started hours before you cast off.
Circadian rhythms aren't fixed so how can an expert be so confident as to call something "perfectly wrong"? A lifetime in the aviation business has taught me how to manage sleep.
 
Circadian rhythms aren't fixed so how can an expert be so confident as to call something "perfectly wrong"? A lifetime in the aviation business has taught me how to manage sleep.
Lots of people work weird hors and simply get on with it. It's always fascinated me how long distance aviators manage their sleep. I've sailed with a few.nthey always seem very relaxed.

In a different life, 6 on 6 off watchkeeping was a bit difficult for a couple of days but one soon adapts.

In a more recent career, trying to get off watch zzz's on a bumpy sea is a tad more of a challenge when you are getting chucked about. Plus noise. Plus being ready to nip up on deck at very short notice to resolve any...issues.

I wouldn't want to do long passages single handed though.
 
@NatalieG, the research shows that 90 minutes is the time of a sleep cycle. Since reading this I've 'noticed' that if I need to get up in the middle of the night, a quick look at the clock will 'tell' me what time I'll expect to be awakening, be it after 1 'cycle' or 2. It seems to be accurate to a couple of minutes each time in fact, which is fascinating in itself.
A thought occurred to me though, during the research how great a margin is the 90 minutes? By this I mean of a 1000 tests, was the 90 minute period the average of samples ranging from 60-120, or much finer than that, 85-95?
 
Looks like NASA like a 4 hour sleep cycle.
"The crew now will take a four-hour nap and be awakened at 7 a.m. EDT on Thursday, April 2, to prepare for the perigee raise burn."
 
jamie N — good question. The 90-minute figure is a population average but the range is tighter than you'd think — most studies put individual cycle length between about 70 and 120 minutes, with the majority clustering 80–100. So it's not as tight as 85–95, but it's not wildly scattered either. What's more interesting is that your own cycle length is remarkably consistent night to night — which is probably why you can predict your wake-up time so accurately. Your internal clock knows your rhythm even if you've never measured it in a lab.

The other thing worth knowing is that cycle length isn't uniform through the night. Early cycles tend to be shorter and dominated by deep slow-wave sleep. Later cycles are longer and more REM-heavy. So a "90-minute nap" in the first half of the night gives you different sleep than the same 90 minutes at 0500.

For passage planning, that's actually useful — if you can only grab one block, an early-night block gives you more of the physically restorative deep sleep. A pre-dawn block gives you more REM, which helps with cognitive function and decision-making. Neither is wrong, but they're not interchangeable.

Buck — fair point, circadian rhythms do shift with habitual schedule, and pilots are the textbook example of trained adaptation. "Perfectly wrong" was tongue-in-cheek, but the underlying point stands for most cruising sailors who keep roughly normal shore schedules: 0100–0700 puts you off watch through the deepest part of the circadian trough and then wakes you at the worst possible moment. Someone with years of shift work or aviation experience will have a different baseline — but most two-crew passage sailors don't have that training.

Natalie
 
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