Canadian investigators fault six-on, six-off watches in tugboat sinking

Fatigue and the six hours-on, six-off watch system widely used by mariners were central factors in the October 2016 Nathan E. Stewart tugboat sinking in British Columbia, Canadian safety officials concluded.

In reviewing the Oct. 13, 2016, grounding and sinking in the Inside Passage, the Transportation Safety Board of Canada reached many of the same findings as the U.S. National Transportation Safety Board did in its December 2017 report.

Both reports found the Stewart’s second mate dozed off before missing a course change and running aground with the barge DBL 55 on Edge Reef in the entrance to the Seaforth Channel just before 1 a.m.

NTSB officials suggested a pilothouse alerter system — a monitoring system that requires periodic inputs from a crewmember or it sounds an alarm — might have helped avoid the accident. Those alerter systems are being phased in as part of the Coast Guard’s Subchapter M safety requirements for towing vessels.

The Canadian TSB report takes aim squarely at fatigue dangers in the maritime industry, describing how the second mate was unable to get sufficient rest during the six-on, six-off watches used by the Kirby Offshore Marine crew.

When he came on that night to pilot the 95’4″x32’x12’, 3,400-hp Nathan E. Stewart and its 287’6″x77’8″x8’ double-hulled barge on a southbound transit to Vancouver, British Columbia, the second mate had slept between 4.5 hours and 6.5 hours on each of the preceding three days — in the morning, but not in his evenings off-watch, the board reported.

“As a result, at the time of the grounding, the second mate had been awake for up to 13 hours,” investigators wrote.

An assistant tankerman was on watch with the second mate, but was off the bridge tending to other duties just before the grounding. After failing to contact the second mate by intercom radio, the tankerman was making his way back up to the bridge when the grounding happened.

Navigational alarms that were turned off or the bridge watch alarm suggested by NTSB officials could have kept the second mate from falling asleep and alerted the other crew members, the TSB investigators wrote.

Battered by swells against the reef, the tug sank about eight hours after grounding, spilling 29,000 gals. of fuel that required a month-long cleanup, and bringing renewed calls for restrictions on petroleum shipments on the Inside Passage.

The TSB report focuses its recommendations on better fatigue management in the industry.

“The use of the 6-on, 6-off shift schedule is a longstanding practice in the marine industry and was not designed according to principles of modern sleep science,” the report declares.

“Although the 6-on, 6-off shift schedule has been called into question by various studies and experts internationally, it continues to be used throughout the marine industry. For example, in this occurrence, the watchkeepers of the Nathan E. Stewart had been working this schedule for over 2 days prior to the grounding. Opportunities to sleep were provided, but the second mate’s inability to nap, combined with the sleep-inducing conditions on the bridge, led to increased fatigue and resulted in the second mate’s falling asleep while on watch.”

There is “a compelling need” for the industry to take on fatigue dangers, and adopt fatigue management plans to keep crews alert, according to the report.

“Implementing effective fatigue education and awareness for watchkeepers is one step that will assist the marine industry in going beyond the regulations to mitigate the risk of fatigue. Implementing comprehensive FMPs within the marine industry will bring it in line with approaches to fatigue management that have already been adopted by the rail and air transportation modes,” the report says.

The board specifically calls for the Canadian Department of Transport to require vessel owners implement comprehensive fatigue management plans specific to their operations.

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About the author

Kirk Moore

Associate Editor Kirk Moore was a reporter for the Asbury Park Press for over 30 years before joining WorkBoat in 2015. He wrote several award-winning stories on marine, environmental, coastal and military issues that helped drive federal and state government policy changes. He has also been a field editor for WorkBoat’s sister publication, National Fisherman, for almost 25 years. Moore was awarded the Online News Association 2011 Knight Award for Public Service for the “Barnegat Bay Under Stress,” 2010 series that led to the New Jersey state government’s restoration plan. He lives in West Creek, N.J.


  1. Avatar

    Not taking time off seriously. 12,’s are even worse I think. Because if ya couldn’t sleep or woke up early. You still have 12 straight hours to stand watch. Wich seems to be too long anyway to be “really”alert for anyway. Boils down to people not taking their job and safety seriously…smh

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      How does taking your job seriously have anything to do with your ability to sleep? That’s an uneducated opinion stated about studied results. The Navy has been studying 6 hour watches for years and is calling for change, and their research involves information much more factual than “it seems”

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        Rob Aitchison on

        I prefer 8 on 4 off, 4 on 8 off. That 8 hour off period seems to do the trick. I used to do 6 on 6 off for 28 days straight. You become a zombie just a few days in.

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        I was a tugboat dispatcher for a major transportation company in Connecticut …..Someone decided to do 12 on / 12 off….Midnight to Noon….truly exhausting because the other office staff arrived at 7 a.m. And we still had 5 hours to go as we were getting more tired…..this was truly exhausting… the Navy we threw in some 4 hour shifts during a week which seemed to help with exhaustion….tugboat dispatching is an important position and exhaustion has no place in that position…..just my opinion……

      • Avatar

        I worked 6 on 6 off as a deckhand on inland tugs for me it was tough by the time I ate and was cleaned up exc. I was lucky to get 3 or 4 hours and many times I could not sleep or adjust to the schedule.

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      Timothy Picou on

      I work the 6 on 6 off problem is and I seen it happen crew don’t go to bed right away won’t to stay up on phones and games that’s a lot of the problem I personally like 6 on 6 off 12 hrs to long on and 12 hrs to long off caint sleep that long and the 8 and 4 really sucks just my opion

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    Dennis O’Leary on

    This goes back to the time before “Uninspected towing vessels” required any license at all to operate. While inspected vessels with “Masters and Mates” required a three watch system on long voyages the uninspected vessels did not. Then “Operators” of these vessels were licensed but because they were not “Masters and Mates” within the language of the Merchant Marine Officer Competency Act they were exempted from the three watch requirement. Finally when the rules changed and “Operators” became Masters and Mates operating companies successfully argued they should not be required to operate under a three watch system simply because of a name change of their billet. Ludicrous because it was the same argument they had previously used to prevent 3 watch system because they were operators not Masters and Mates. If it’s not safe for a ship to work watch for watch it’s not safe for a towing vessel either. All vessels operating 24 hours a day should be on a three watch system. Period.

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      33 years of work 6 on and 6 off. Never had a problem with it. In all that time the company I work for has only been 1 accident due to a pilot falling asleep and it happened during the middle of the day. Always wanting to change things because one guy couldn’t sleep in his off time and wasn’t smart enough to pass on to another crew member that he was tired. So period that

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      I totally agree. I have been working 6 on 6 off for 43 years and you never get used to it. I worked 8 on and 8 off and never was tired. But 12 on and 12 off is ridiculous. Way to long to be watching radar and eye fatigue is very bad

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      if they start putting 3 person watch then our pays will be cut in half. And if they do that Deckhands will just stay on deck because they will make the same money as the pilots. If the guy was that tired he should have had his deckhand stay in the wheelhouses with him. And before they went off watch he should have helped his deckhand with his duty’s. And you do not want a pilot on watch for 12 hours straight. I have worked both line haul and harbor.

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      It’s my understanding there is not enough operators to go around now. It’s seems changing to a three watch system could be used to force the industry to be better stewarts in training the new pilots they need.

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    John C. Falgout (retired Vessel Master) on

    I’ve worked this 6 hr on / 6 hr off watch when I first started in the offshore industry on tugs and workboats for several years before we went to a 12 hr on / 12 hr off watch. The ideal watch would have been 8 hr on / 16 hr off watch or 4 hr on / 8 hr off like some oversea voyages. But alas, due to reduced manning practices some vessel companies put us through, we couldn’t crew up vessels that way.

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    David VanBuskirk on

    Make more paperwork it might save a life I have spent over 30 years doing 6&6 I never feel asleep on watch but if it was a second mate that should be a 4& 8 watch

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    Until the Coast Guard and other regulatory agencies require three wheelmen and at least three deck crew and implement eight hour watches nothing will change the fatigue it puts on crew.

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      I agree 100%. The health of the industries towboat and offshore Captains, Mates and General deck crew has fallen to the inth degree. We work a 30/30 schedule in the wheelhouse.. some still maintain 30/15. The deckcrew is 30/15. Everybody works 6 hrs on/6 he’s off. I’ve been told 8 hr watches in the wheelhouse wouldn’t work because one person works 16 hrs and the other only 8 hrs. I totally disagreed. Sleep deprivation is rampant in the industry. What is called “good sleep” on a boat is only a nap anywhere else.

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    So what plan do they propose. It’s fine to lip service that it’s needed and should be implemented. What does the statement “Specific to their operation” actually do to make companies act??…..fiddlesticks!

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    John O'Reilly on

    Way back when people stood 4 and 8 watches this was not as much of a problem. The regulatory agencies have allowed operators minimum manning rules which exceed common sense. It may not be the most cost efficient way to deal with the situation but what price safety?

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    Capt Edward McDevitt on

    For sure more demands on the mariner, extra work on watch,, ,4 on 4 off with a third mate,, these large ATBS Are like tankers that had 30 crew members,!

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    I did it for years and never used fatigue as an excuse for failure. Remove television / electronics from the ship so people rest when their six are up.

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    Scott Winter on

    Without adding another man to the watch system, there really isn’t any effective way of resolving the issue. Bells, whistles and alarms may help wake you up to avoid a grounding or a collision, however, that is not going to alleviate the underlining issue of fatigue. And let’s be honest – adding another man to the watch is likely not going to happen, because of the increase in labor cost and many boats weren’t built for that many men. Therefore, there is no need to address the issue by creating even more regulations. Captains are becoming clerks with all the paperwork that is already required.

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      We need someone else too help with the paperwork and the computer work. Sometimes it takes people an hour or two just to put their tow in a computer just so their office can see what they have in tow. And rose point is the worst thing they put on a boat. Now boats don’t talk on the radio when passing one another. Everything is done on rose point

  11. Avatar

    I’m done 6 on 6 off for close to 40 years never had a problem with fatigue but then I sleep both off watches a minimum of 4 hours

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    Robert Knight. vetus nauta. on

    Anyone who believes they can work efficiently whilst doing 6on 6off watches is in denial. It also contravenes MLC 2006 hours of rest requirements. “I can do with only 5.5 hours of sleep” is an out of date macho philosophy of ignorance.

  13. Avatar
    Shannon Gurganus on

    I’ve been working this 6 on 6 off system for 26 years and yes there are times I don’t sleep like I need too but you do that at home or anywhere! If you didn’t sleep well have the crew know so they can maintain a regular schedule to check on you way more often! That’s what I do and it works out fine! All the new rules put out on the health parts with the new health card I will say something will have to change cause if you have sleep apnea they give you more hell about that and the Dr’s can’t get it in there head you can’t sleep a full 8 hours on our jobs!

  14. Avatar

    The best captains I’ve sailed for move to 4 and 8 as soon as we’re no longer at the dock. The only reason not to do that is because the captain doesn’t want to stand a watch.

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    Captain Steven Oravets on

    Of course he fell asleep. six and six watches guarantee you will not get adequate rest according to modern sleep science. Sleep deprivation has been proven to cause permanent brain injury.

    Sure, I have worked six and six watches for over forty years without an incident. Guess what? I was lucky. I have experienced micro-sleep, diminished mental acuity, and fatigue due to lack of sleep. Just lucky, that’s the the only thing that separates me from the second mate who got into trouble because he fell asleep. Plain old luck.

    If the man on watch was a second mate that means the vessel was crewed with three licensed people for the wheelhouse. The lazy-ass captain should be sanctioned as well. He had enough wheel house personnel to operate a three-watch system yet he put his own comfort ahead of the safety of the vessel. Sounds typical to me of human nature.

    Claiming that six and six watches provide adequate rest because I didn’t have a problem is just plain ego-driven denial. Denial of an obvious problem. That problem is the inadequate rest periods aboard two-crew vessels moving tons of cargo with the potential for disaster including the loss of life.

    Know why it’s still an issue after fifty years of solid sleep science. Money! That’s it. Plain and simple. I mean, the solution to adequate rest aboard commercial vessels has been around even longer than modern sleep studies. It’s called the three-watch system. Four hours on duty and eight hours off duty. I don’t mean to be Captain Obvious here but the mental masturbation the subject of adequate rest time on vessels generates is comical. Everyone knows the answer to the problem but no one wants to pursue the only viable solution.

    Wheelhouse Alerters? oh yeah, thanks for them! Now I have a great alarm clock to wake me up at whatever interval I choose.

    I can offer another long-term observation on the marine industry. How many maritime accidents were attributed to other causes while mariner fatigue was never listed as a contributing factor. I personally know of three such accidents over the course of my career, two of which involved fatalities.

    What if drunk driving was still being studied endlessly without any change in regulation? How many lives would have been lost over the past fifty years? Fortunately, Drunk Driving regulation was changed and I have no doubt that thousands of people like ourselves owe their lives to an honest and fearless approach to the drunk-driving problem.

  16. Avatar

    I am master of an ocean-going tug operating on US East Coast routes. We have a two-watch system, so it’s a 12 hour work day underway. Chief Mate and I work 7 hours on, 5 hours off, 5 hours on, 7 hours off. Chief Mate chose which hours. One off-watch is going to be a nap at best no matter how you split up 12 hours. This gives us a chance at an hour more real sleep during the longer off-watch. I have found it makes a big difference. If at the dock overnight, Chief Mate and deckhand usually split the watch, so each gets a little additional sleep. It’s making the best of a bad situation. I have worked three watches, and it was much better, but it won’t happen in a company that has to compete with others crewing their boats with two watches.

    My question about this incident is, if there is a navigating second mate, why weren’t they standing three watches?

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