A group of women set off on Monday on a grueling journey across the Pacific, in a quest to row thousands of miles for charity.
The women, dubbed the Coxless Crew, are heading out from the west coast of America for a journey of 8,446 miles across the world's largest expanse of open water.
Their daring challenge is expected to take around six months, during which they will set foot on land just twice as they travel the equivalent of more than a third of the distance around the world.
The group will stop off for around five days in Hawaii and Samoa before they come ashore for the final time at Cairns on the north east coast of Australia.
If their journey is successful, the women will become the first all-female team to row this route across the Pacific, the first team of four and will set the record for the fastest Pacific row. They also hope to raise around £250,000 for two charities, Walking With The Wounded and Breast Cancer Care.
During their voyage they are likely to contend with ocean storms, changing currents, a glaring sun that will send temperatures soaring to more than 40C (104F) and possibly the company of an odd whale or two.
And the only thing to shelter them from treacherous seas is a small pink boat. Named Doris, a £90,000 carbon fibre and Kevlar rowing boat just 29ft long and 7ft at her widest point, with two cabins.
Leading the Coxless Crew is Laura Penhaul, a 31-year-old Cornish native now living in Putney, south west London, who is the lead physiotherapist for the British Paralympic team.
Manning the oars are Emma Mitchell, 29, an expedition team leader from Marlow who lives in Portsmouth, and Natalia Cohen, 40, an adventure tour leader based in London.
The rowing quartet will be completed by three different women. Isabel Burnham, 30, a solicitor from Saffron Walden, will join them for the leg from mainland America to Hawaii; Lizanne van Vuuren, 26, a south African osteopath who grew up in Newbury, will take over from Hawaii to Samoa, while Meg Dyos, an estate agent from London who at 24 is the youngest, will help see them home from Samoa to Cairns.
From left-right: Natalia Cohen, 40, Emma Mitchell, 29, Isabel Burnham, 30 and Laura Penhaul, 31
The expedition has been more than three years and £200,000 in the planning, and the crew have spent the last week in their starting port of San Francisco, carrying out final checks and training sessions and making sure their supplies and equipment are all ship-shape.
At 9am British time today, the group rowed under Golden Gate Bridge, towards the south Pacific.
Such a journey is a daunting prospect, and one that the experienced women have been preparing for.
For Cohen, the challenge will be 90% mental and 10% physical, made manageable by breaking it down into comprehensible sections.
"It is ridiculous, a huge undertaking and without doubt will be the biggest challenge I have ever faced," she said. "Though we have obviously done a lot of mental preparation and have to be able to visualise the end at Cairns, I am taking it chunk by chunk. That is how you deal with the enormity of it all.
"It is a journey of 8,446 miles but begins with a single stroke. That is how I am coping with it - stroke by stroke, shift by shift, leg by leg."
The women will row in pairs in two-hour shifts, making painfully slow progress at an average of just 2 knots an hour - the equivalent of 2.3mph on land.
Those off duty will have plenty of lists and routines to run through - filling in log books, carrying out equipment checks and taking great care of personal hygiene to combat the sunburn, blisters and sores they will inevitably suffer in their spartan environment.
And, of course, they will have to sleep.
"What normally happens is that people sleep in one block, for seven to eight hours," Cohen explained. "But out there we will have to go into 'napping' mode, of 45 to 90 minutes. During these we will need to get in a full sleep cycle to allow the body to do its repairs."
They will also need to eat, but it will be far from salubrious fare out on the ocean. Dinners will be freeze-dried expedition food - spaghetti bolognese, shepherd's pie, chicken noodle and curries, with custard for dessert.
But the women will have to each consume a massive 5,000 calories a day - more than twice the usual intake for a woman - and have snack packs full of protein bars, chocolate, nuts, dried fruit and beef jerky to help keep their energy levels up. They are also each sneaking on board a little comfort food - tuna in oil for Cohen, and rice and chicken stock for Penhaul.
The Coxless Crew in action
Drinking water will be converted from sea water and Doris is laden with emergency bottled water, as well as navigation, satellite and communications equipment.
The first two weeks are likely to be among the most challenging as they get used to their new routines and any sea-sickness.
There is 24 hour land-based support from logistics boss Tony Humphreys, who will give them daily updates on weather and navigational issues, but out on the ocean they are on their own.
For the first 100 miles they can be rescued by helicopter, but after that any hope of salvation will be from a passing ship.
Cohen said: "We are out there and at the mercy of Mother Nature, but hopefully we will be prepared for whatever is on its way.
"In really bad weather, when we won't have the strength to row, we will have to put out a para-anchor to swing us round so we are nose to wave, otherwise we can capsize. The boat is self-righting and we have practised this, so we'll just have to strap ourselves in the cabins and ride out any storm."
Aside from the weather, ocean, food and sleep deprivation, painful chafing and gruelling physical toil, dealing with the solitude will be one of their greatest challenges.
Cohen said: "It is going to be pretty boring a lot of the time, so we will have to find ways to keep occupied and in the moment so your mind doesn't start spiralling into areas you don't want it to be.
"We have got iPods and a couple of the girls have got a Kindle so there will be a bit of variety. We will have to break each shift down to what we want to do - chatting, listening to music or an audio book. Emma wants to learn Spanish, so I will be testing her."
They are also conducting scientific research on bone density and tests on their saliva to assess cognitive behaviour and stress.
And during tough moments, the group will find motivation from the charities they are supporting. They have filled their cabin with the names of people who have sponsored them, and will tell stories about them as they go.
For Cohen, the expedition will be a true test of mind and spirit.
She said: "It is important to raise awareness and support for our charities, but I would be lying if I said there wasn't a personal intrigue to see how we are going to overcome every scare and challenge we will face on a daily basis.
"For me, life has always been about the journey, and that is how I have chosen to live. I have always been fascinated by the mind and human spirit and what makes us push forward and keep pushing, and this journey will be an opportunity to find out what that is.
"It's going to be ridiculously challenging, and I'm looking forward to seeing how we pull together as a team and draw on each other's strengths.
"I am also really looking forward to seeing phosphorescence. I have heard people mention it, and I think it would be magical to be surrounded by that and a few dolphins.
"I am just really looking forward to being insignificant and being forced to be in the moment, and hopefully some insights will come from that."
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