Sleeping & avoiding exhaustion

Passage planning when sailing solo has an additional factor to take into account, sleep, with two or more on board, especially with self-steering, even a novice should be able to spell the skipper while he or she has a nap, but solo you have to stay awake when there is land or traffic about and that can lead to some very bad things:

Symptoms of fatigue (Thom, 2003) include:

Lack of awareness.
Diminished motor skills, poor hand eye coordination, 
Obvious tiredness, drooping head etc.
Diminished vision – difficulty in focusing.
Slow reactions.
Short-term memory problems.
Channelled concentration / Cognitive Tunnelling (best to Google this one!).
Being easily distracted.
Increased mistakes.
Abnormal moods.

In extreme cases, not uncommon for long distance single handed sailors for reasons of fatigue, isolation and other factors, fatigue can lead to hallucinations, hearing voices and emotional inertia, these latter effects are addressed in chapter 2 of (Evens, 2015) who also looks at sleep options including:  

  • Polyphasic Sleep
  • Short naps 
  • 2 or 3 longer sleeps or one longer plus naps synched to natural rhythms.

John Passmore's Rival 32 "Samsara" in
Baltimore 2019.
When to start napping: John Passmore, a seriously experienced offshore solo sailor advocates on his Blog (Passmore, 2019) starting 20 minute naps immediately after starting, a good idea if using the napping strategy but with lots of boats around, perhaps at the start of a Jester or in or near a shipping lane that may not be possible, for instance on the 2019 JBC we were beating to windward until past the Lizard with multiple boats in close company, at one point around 23:00  I was on starboard tack heading out to sea to keep well clear of the Lizard over-falls (a good move as I gained on several boats who were further in) when another boat which shall remain nameless, came in on a collision course  (with AIS not working, so no automatic alarm) and kept on coming even after I shone the powerful torch on the sail (mine and his!) I had just started to tack when he ducked under my stern. 

If we had both been asleep there would have been a collision and I don’t want “I had right of way” as an epitaph (or more correctly these days “I was stand on vessel”).

Along the south coast and around much of UK and the channel, even in good weather there is in my view just too much going on to risk more than 20 – 30 minutes below deck, if that. 

Consider Lyme Bay, it is over 50 miles from The Bill to The Start and at the midpoint you are > 20 miles from land. But, it is still very busy, all of the pleasure craft crossing will be following essential the same track unless beating to windward, to the east they will pass either 1 - 2 cables or 4 miles off Portland Bill (more in poor weather) and many will be passing not far off Start Point, commercial traffic will be on the offshore route as will most traffic going eastward (I occasionally use the inshore route going east but timing usually precludes it). 

Then there are commercial and sports fishing boats, often without AIS, making unpredictable course changes as they chase fish around the bay. The North Sea is no better with lots of windfarms and associated work boats to worry about in addition to the other hazards

A typical typical trip from the Hamble River to Plymouth with variable
but generally good winds. 35 hours and 145 miles over the ground.
I missed the tidal gate at Start Point in light winds and getting into 
the Hallsands anchorage behind the point for a sleep was not practical,
by the time I could get there the tide would had turned so I took advantage 
of that and carried it to Plymouth.

So, the plan must take account of rest stops until well away from danger.

It is useful to have an idea as too how long you can remain awake and functioning, it will vary from day to day depending on workload, prior rest etc. but is a useful guide. Assuming I am well rested and starting at a sensible time in the morning, I am usually OK for about 36 hours; I will have a noticeable drop in performance for an hour or two from about 04:00 and a bigger one after lunch on the second afternoon and then perk up again for a few hours. As I get older it is getting tougher.

The problem is the 36 hours starts from wake up time on the day of sailing and in tidal waters that can be a restriction. If I am heading west from the Solent I choose the start day (near a neap tide) for the best start to cross Lyme Bay or to get into Portland harbour so as to get some rest before using the inshore route around the Bill as soon after wake up time as practical given the tide and sun rise. But that is not always possible, perhaps vacations are fixed (not normally a problem for us oldies) or you need to be somewhere on a set day. 

Generally you have little choice when well into the voyage but sometimes you can find an alternate route, perhaps the other side of an island, if not, leg lengths will probably have to be adjusted.

Longish legs will clearly be the biggest problem, on a round GB trip this is likely to include crossing Lyme Bay, the Bristol Channel and / or the Celtic Sea and possibly the Thames estuary. The trip between the Solent and The Dover Straits can also be problematic with Brighton Marina (not my favourite and expensive) often the only viable stop if you can't anchor somewhere.

If winds are onshore down the east coast then several other legs become problematical with most anchorages becoming untenable and a lack of harbours usable at any state of the tide - I got stuck in Blyth for 12 days with no window long enough to safely get further south.


Waiting in Blyth for a weather window.

But light or contrary winds, tidal gates, races / roosts / over-falls can disrupt the best laid plan. Missing a tidal gate when crewed is a pain but not usually disastrous, missing one when you are already tired and the next safe haven is a good distance away could be very bad news, so to make a gate or a safe haven you will probably find yourself using the engine more often than you would crewed.

References:

Evens, A., 2015. Singlehanded Sailing Thoughts, Tips, Techniques & Tactics. Blacklick: International Marine / McGraw Hill Education.

Thom, T., 2003. The Air Pilot's Manual - Vol 6, Human Factors and Pilot Performance. 2nd Edition with revisions by Godwin ed. Shrewsbury: Airlife Publishing Ltd.

Steele, S., 2011. UK and Ireland Circumnavigator's Guide. 2nd ed. London: Adlard Coles Nautical.


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