Tag Archives: Cook Strait

Limiting Factors in Marathon Swimming – Part 2 – Environmental Factors

In Part One I covered the physiological limiting factors in marathon swimming.

The various environmental aspects of a swim are not insignificant. They are especially important in that they all lay outside the swimmer’s control and often even outside the control of the support crew.

Water Temperature


This is generally a known factor prior to a swim. Swims are either cool or cold water like the English and North Channels or warm water swims like Maui, Rottnest, Manhattan or Chloe Maccardels’ upcoming Cuba to Florida attempt. A few fall into an intermediate category defined more by the swimmer’s experience, such as the Catalina and Gibraltar Channels. Sudden changes in temperature are rare in marathon swimming and where they are possible they are also understood; such as South Africa’s west coast which is prone to sudden wide water temperature changes, and the California coast where the sudden transition from very deep water to a shallower continental shelf very close to the  mainland can cause cold water upwelling at the end of a marathon swim. Air temperature is obviously much more variable and a condition of the weather but extremes of air temperature are not usual during a swim. A five degree Celsius differential can be significant for a swimmer if such a drop is also accompanied with a breeze or wind which can sap the swimmer of body heat.


Lion's Mane jellyfish
Lion’s Mane jellyfish

The recent and future attempts at a distance and time records by necessity are held in warmer waters such as Cuba to Florida.  These water are home to jellyfish with debilitating stings such as Box Jellyfish. While the cold waters  of the North and English Channels are home to Lion’s Mane and Portuguese Man O’War’s endurance records are less likely and jellyfish stings in the English Channel are rarely more than intermittent, though the North Channel (the Mouth of Hell) can have miles of Lion’s Mane blooms, part of what makes it the ultimate channel swim. Attempts to swim in these waters divide swimmers in two ways: whether attempts should be made in locations not considered possible without additional protection or exceptions to the usual rules, and if so are jellyfish protection suits acceptable or the thin edge of a wedge that will inevitably lead to more overt (or hidden) performance enhancing suits? (See Evan’s analysis of his survey of marathon swimmers for an excellent overview of the contradictions of divisions and unity in the community).


The Man In The Grey Suit is a subject of great concern (and discussion) for distance swimmers. Not of any real concern here in the north-eastern Atlantic, they are a greater hazard in the warmer waters elsewhere, particularly California, the Caribbean, Hawaii, South Africa and Australia. The Cook Strait Channel swim in New Zealand is unique in having a shark evacuation rule. Shark cages have been used for marathon swims in the Caribbean and South Africa at least. Shark cages are however considered swim assistance as they increase the swimmer’s speed through eddy current drag. Other possible control methods include electronic shark repellents (whose effectiveness is not entirely assured or quantified), armed boat crew or armed or otherwise scuba diver outriders.


These are amongst  the most variable of environmental factors and therefore potentially also the most limiting. Because swimmers move slowly relative to even a sailing boat, we are vulnerable to slight deviations, miscalculations or just insufficient data, the most likely cause. Even in such a well-travelled and mapped location as the English Channel, especially for swimming, pilots will occasionally speak of tides arriving early or late or with a difference force than expected. Tidal currents are understood at a larger scale, hundred of years of navigation have mapped the seas for craft, not for swimmers. Tides act in a similar chaotic way to a weather system, which means that small deviations will always creep in. The only way to improve accuracy of prediction is to improve the data, and this is not practically possible or even desired for small tidal variations. As swims occur in less well-known or new locations, the likelihood of discovering unknown local variations outside marine charts increases. Half a knot current, barely detectable to a boat, is enough to deviate a swim over hours from a projected or necessary course.

Global tides
Global tides

Crew and boat

Any English Channel pilot will confirm that one of the most likely causes of unsuccessful Channel swims is poor selection of support crew. The most likely cause is mal-du-mer, seasickness. For some people seasickness is a completely debilitating ailment that can sap all willpower and strength and there is no way to know whom it will strike. The solution of course is to have experienced crew. Even this can fail because people experienced on powered craft will be at the mercy of the choppy water amplified on an almost stationary craft. Other crew issues can also arise, whether accidents or other illness. Anyone who hasn’t been on a rocking boat looking down on a swimmer is unlikely to understand! And not unknown are mechanical problems on the pilot-boat. Most pilots are by necessity practical mechanics able to address problems as they arise, but not all problems can be fixed with a wrench and hammer while rocking about on the sea.

Channel boat The Viking Princess
Channel boat The Viking Princess out of the water


Weather changes are the bane of English and North Channel swimmers particularly. Other Channels like Tsugaru and Gibraltar and Cook are also subject to constantly variable and unpredictable weather patterns. If you are used to the predictable weather of the west US coast, with morning offshore and afternoon onshore breezes, knowing your swim will almost certainly take place with a 48 window, the difficulty of allocating two weeks or even long (like the North Channel) and still being completely unsure of getting in the water is shocking. Weather constraints obviously ran the full gamut. In the North, English and Gibraltar channels the main concern is wind (and its effect on the seas). Fog can also be a problem with 2012’s Channel season infamously seeing three solos on one day abandoned within a kilometre of France for the first time in 137 years. I’ve warned previously that fog may be the most dangerous weather condition for swimmers. In warmer humid climes like Round Manhattan, and the Caribbean, lightning storms are a serious cause for worry, a swimmer or boat caught exposed out on the water is in real danger. Having to wait for or even postpone a swim is something many marathon swimmers have undergone and the mental pressure this brings is often not inconsiderable, which I will discuss further in the next and final part.

Coming in part three, Psychological Factors.


Stephen Redmond's Cook Strait map

Stephen Redmond’s own Cook Strait report & GPS – Widowmaker swim

(I accidentally sent out a brief version of this post yesterday to subscribers, sorry about that).

Some of you will have already seen Stephen’s own post-Cook swim report. He emailed me on Saturday night so I can put it up here. He titled it a “Widowmaker swim”. Stephen is not prone to exaggeration so for him to say this, well it’s a sign of extreme conditions. I’m leaving his report untouched, as you get a better feeling for his exhaustion and elation. His time was just under 13 hours.

He was on his way directly to Hawaii yesterday for the very slight chance he’s get a weather window, but the pilot wasn’t very optimistic. We all have our fingers crossed for him.

In yesterday’s (deleted) post I mentioned the horrendous cost (especially Tsugaru) for Stephen. I’ve asked one of the team if they can give me any details for an account or fundraising page that people who wish can contribute directly to. I’ll update as soon as I have anything.

The Philip Rush mentioned is a famous English Channel swimmer (single, two-way AND three-way), International Marathon Swimming Hall of Fame, organiser and head of the Cook Strait Association.

From Stephen:

His old man
Just an update on the cook strait swim. Has been a great trip to new Zealand meeting incredible people once again
Coming to the other side of the world  I thought it would be very lonely as I traveled alone but the Irish in Wellington have been incredible and looked after me and helped all week Dermot in the D4 bar fed me all week and Roslyn Murphy and Marie came on the boat as support team. The positivity was overwhelming and the swim is more theirs then mine as I could not let them down.
  We got in on Friday after an aborted attempt on valentines day where we steamed out had a look and Philip rush the swim coordinator and head man makes the call he supply’s a five man team who’s only mission is to get you across very professional and all I have to worry about is the swim which is enough.
 The call came through on Thursday that we had a chance on Friday after 3
Days of gales I was delighted had been training all week in Wellington harbour and this was our only chance this week as tides would be gone and I was due to fly on Sunday 19 no pressure then.
 Friday was flat calm with sun shining as we steamed over to the south island to start swim  so could not be better was well prepped and rested after flight down  passing the brothers which are two rock near south island Philip gave me the ok to grease up stretch and get ready  it is so unpredictable here but until you are getting in the water  you do not believe its happening  on this swim Philip is right next to you for the whole swim   In a small rib and the larger boat lays off in support for any thing that you need . Finally into the water which was surprisingly cold I swam into the rocks  and the guys guide me to  a small beach I managed to stand up quick pictures and clocks started Ann’s away  huge relief to be swimming.
  First 4 hours was heaven screaming along in the water at 54 strokes per minute perfect conditions. Stomach fine feeds great smooth and quick good communication with Philip and following his directions was simple . We had tracker on for this trip so people could watch it live on their computer in the fifth hour  the northerly wind starting to come up sooner  then forecast this worked against the tide which was coming southerly to create 6-8 swells  and the wind kept me cold in the water even though sun was shining.  We swam on through say encountering only a couple of shark which I never seen but Philip and crew spotted they stayed for about an hour inquisitive I guess .  The weather continued to deteriorate through the afternoon the poor girls on the large boat being seasick but still updating everyone with texts and Facebook and recording my stroke rest throughout the day  great people.
  The tide was just trying to kill me we had to cross over it so when it changed we  could use it to bring us in god was testing us to the limit for long
Periods it felt as if I was not moving at all but stroking harder then ever prayers and mantras were used over and over  never looking forward just at Philip breathing every six strokes due to the swells now tough stuff no point moaning this is what i wanted this is
My swim do I give up and spend the rest of my time in regret no. Just cannot happen . We are sweet around the point by tide and miss landing. Ending up in another bay where god seemed to be moving furniture Jesus it was rough darkness fell lights on mask and trunks we carried on wishing to get out  every time I stopped in despair I lost 50 metres cruel water Philip explains that I only have 1 k to. Do I can make out buildings on shore where a electric power line runs comes ashore from south island so close now close I keep telling my self  Philip fucks me out of my doubts and keeps me going as I am exausted and close to death. It take3 hours just to swim 1.5 k
In the end and when I touch rock there was no joy i just cursed that piece of rock and grabbed hold of it  swim done I had to get back to rub which was being covered in waves guys soaked and freezing from the day incredible people who got me over the cook straits I clamber he’d first into bottom of the boat telling the to get the f—k out of there  back to main boat in shock now pucking and hypothermic after swim they clean lanolin of as best as can be done and get  me dressed  as quick as possible  huge joy and relief all round I had been very lucky Philip explains that they had never had a swim finish I such  rough conditions  down on the floor of the boat for the steam back safest place to start recovering dry retching and puking acid all the way back everyone in high spirits how could I have let these people down truly a team effort very rough slow steam against 24 knot northerly wind .
At last we come into are berth o be meat by over 100 irish people draped in Tri colours who had waited hours for us I was overcome and in tears at this  these guys are are loss but new zealand s gain and it is great to know they are here as the Irish never give up adapt overcome and succeed  . Huge community  help and involvement back home with no one sleeping in Ballydehob and castledermot  all of this I used to get over  thanks to everyone for prayers and  belief .
Post swim badly badly burnt on backs of legs and face shoulders good freeing up getting ready to fly to Hawaii tomorrow very tired  but delighted to be alive told death to get lost in the end we
I have no word for how great the people and new zealand has been to me I am humbled. By it all thank you all I can never repay the debt I owe
Kind regards Steve redmond
Hope this is not too
Crazy sir

Fastnet swim

Stephen Redmond completed Cook Strait this morning

I’m sure 99% of you know by now that Stephen was successful on Ocean’s Seven crossing number 5, finishing this morning (GMT) but just in case you are part of the 1% …


(I was away swimming today, he was only about 1k from land when we started, and Lisa and Liz updated us during the session).

Stephen Redmond in Cook Strait tonight.

Irish Water Monster, Stephen Redmond rescheduled his remaining Ocean’s Seven swims during the winter. (I’d been meaning to ask him to write again about them).

But anyway, he is currently in New Zealand for his first big swim of this year hoping tackling the Cook Strait hopefully starting at 5pm GMT tonight. Open water swimmers worldwide but especially the Irish swimmers are all behind him wishing him success.


Here’s his tracker from Liz (Chairman of Sandycove Island Swim Club).

Update: Well the tracker looked odd. According to Lisa, the swim was called off for tonight.  Let’s hope there is a weather window tomorrow. I think only marathon swimmers and climbers understand this pressure.


Penny Palfrey in Dover

Ocean’s Seven – Six down, one to go for Penny Palfrey

From Penny Palfrey’s site:

Ocean Seven – 6 Down 1 to Go For Penny

The [O]cean’s Seven is the marathon swimming equivalent of the mountain climbing challenge, the “Seven Summits”. But unlike its land based equivalent, the ocean’s seven has never been completed.

(Donal’s note: The Ocean’s Seven was proposed as a goal by Steve Munatones. Steve, did you think someone would get so close so quickly? Although I guess it always seemed that Penny was the most likely?)

The seven swims referred to, are as follows (together with details of location, distance and particular difficulties/challenges) :

English Channel (England to France – 34k) – cold, strong currents, heavy shipping traffic. (Another note from Donal. I wish to dog it had only been 34k. 60k for me!)

Cook Strait (between north and south islands of New Zealand – 26k) – cold, strong currents, marine life

Molokai Channel (between Molokai and Oahu, Hawaii – 42k) – big oceanic swells, strong currents, marine life

Catalina channel (California, Los Angeles – 33k) – swum at night, cold, marine life

Tsugaru Strait (Japan – 20k) – very strong currents, cold, often rough

Strait of Gibraltar (Spain to Morocco – 15k) – strong currents, windy, heavy shipping traffic

Irish North Channel (between Scotland and Ireland – 34k) – very cold, often rough and windy, nasty jellyfish

With Penny’s recent conquest of the Tsugaru Strait, between the Japanese islands of Hokkaido and Honshu, Penny‘s now completed all of the above, except for the North Channel.”

Penny Palfrey in Dover