An investigation by the Marine Accident Investigation Branch (MAIB) is under way into the sudden and tragic loss of the British sailing yacht Cheeki Rafiki and its four-man crew.

Skipper Andrew Bridge, aged 21, from Farnham, Surrey and crew Paul Goslin, 56, from West Camel, Somerset; Steve Warren, 52, from Bridgwater, Somerset and 22-year-old James Male from Romsey, Hampshire lost contact with yacht agent Stormforce Coaching on 16 May.

After considerable delay owing to the search being cancelled by the US Coast Guard (USCG) and later resumed after public and political pressure was brought to bear, the empty upturned hull of Cheeki Rafiki was discovered following a search covering more than 17,540 square miles of ocean and involving air crews from the USCG, US Air Force, Canadian military and Royal Air Force, plus the Coast Guard Cutter Vigorous and a US Navy warship and helicopter.

Yachts taking part in the ARC Europe rally also diverted course to join the search efforts, along with many merchant vessels.

A US Navy warship surface swimmer reported that Cheeki Rafiki’s cabin was completely flooded and its windows were shattered. Navy crews observed that the sailing vessel’s keel was broken off, causing a breach in the hull.

Underwater imagery identified the liferaft secured in its aft storage space, indicating it had not been deployed.

So what happened?

The Atlantic Ocean tragedy raises questions about how and why the Beneteau First 40.7 yacht lost its keel mid-voyage, leaving four such experienced yachtsmen without time to deploy their liferaft.

Official opinions are scarce while formal investigations are carried out. A MAIB spokesman said: ‘The MAIB is investigating the loss of the yacht Cheeki Rafiki and her four crew in the Atlantic Ocean and will publish a report in due course.

‘We are not giving a running commentary on the investigation.’

Stormforce Coaching would only comment: ‘This is a terrible moment for the families and friends of the crew of the yacht Cheeki Rafiki, Andrew, James, Paul and Steve. We all share in their sorrow after this tragedy.

‘We would like to thank all those who have participated in the search efforts.’

Cautious words, but sailors around the world are discussing the tragedy: what happened, who is to blame and what lessons should be learned.

‘Keel bolt failure’

Former RAF pilot and yacht charter company owner Jim Baerselman, who is now a retired full-time cruiser and a member of the Cruising Association Council, said: ‘This was a dreadful tragedy, and I’m dreadfully sorry for all those who have been directly affected.’

Based on photographic evidence, Mr Baerselman believes the tragedy was caused by structural failure, rather than by hitting a submerged object.

He said: ‘Cheeki Rafiki photos do appear to show that the keel failed laterally, rather than hitting something with its leading edge. The keel seems to have loosened by degrees, causing a leak.

‘Eventually, some port-side bolts pulled right through the hull, taking laminate with them, and the keel flopped to starboard, peeling off more laminate. Without stability, the boat rapidly inverted.

‘Other bolts failed either before this event through fatigue or after due to stress, leaving clean holes in the hull.

‘This isn’t the first case of a lateral keel failure.’

Chartered Surveyor (Admiralty & Maritime) and author, Captain Ed Geary, suggests a similar scenario but lays the blame squarely with the keel bolts.

‘When total failure occurred the keel fell free, causing damage to the hull laminates amidships. The damage, limited to the hull/ keel join (amidships), is displayed in the US Navy photo.’

Capt Geary added: ‘Whether the keel struck anything is irrelevant considering the undamaged apertures of the forward and aft keel bolts; their clean separation indicates the keel bolts were structurally unsound.

‘During the 640NM voyage north the approximately 3,500kg keel was only partially held against the flat hull surface by the defective keel bolts, which initially allowed the keel to move with limited ingress of water. Unknown to the crew because of the sea state, the keel would have experienced a slow swinging motion before it eventually dropped from the hull.

‘The ultimate failure of the keel bolts would have allowed the keel to drop with an immediate change and rise in Vertical Centre of Gravity, resulting in immediate capsize. Capsizing in the turbulent seas during the night, the unsuspecting crew would have had little opportunity of survival.’

A note of caution

PBO contributor and engineering expert Vyv Cox agrees there is no indication that the yacht hit a submerged object and that the leak occurred without any prior incident.

Nevertheless, he adds a note of caution to the keel bolt failure theory, saying: ‘It is a big leap to state that failure of the bolts was due to corrosion or fatigue. Both of these certainly do occur.

‘I have experience of keel bolts that have suffered crevice corrosion but it would be incredible if every one, or even many of them, failed in the same way, as each is caused by leakage of seawater in its individual drilling through the hull.

‘What I think I can see is rust marks around the aft keel bolt hole that may suggest there was an existing problem of bolt looseness or poor sealing, allowing the keel to corrode in that area.

Stretching that a bit, it could be that all the bolts were a little loose. Fully-tightened bolts do not fail in fatigue but loosened ones do, so there is a possibility that operator error may be the root cause. However, this is pure speculation.

‘It looks to me, based only on the same photograph, that at least some of the bolts pulled through the hull. It also appears that this happened after the boat inverted, accounting for the obvious keel mark on the hull.’

Lessons to learn

One of the important questions raised by the tragedy is what is needed to survive a sudden inversion, says Mr Baerselman.

He added: ‘I’ve seen too many boats with liferafts which can’t easily be launched single- handed. My vote is for an external mounting on the pushpit which can be released with a pull on a lanyard.’

Like Capt Geary, he believes keel failure has a ‘very high’ probability of loss of life.

He added: ‘Given the life-threatening consequences of losing stability, very high design safety factors have to be used to ensure keels can’t fall off.

These must allow for:

• Bending movements at the hull joint caused by peak possible inertia forces (the boat’s hull being rapidly rotated by a steep wave, with some 3,000kg mass sitting at the end of a 2m plus plank being forced to follow suit!). Such moments are unpredictable, and well beyond the approximate 6,000Nm of the horizontal static case to support a cantilever.

• Continuous reversals of this lateral bending moment causing structural softening over time, or metal fatigue if keel bolts take any bending stresses.

‘The fact that the keel fell off demonstrates design failure. Whether this was a failure to design or implement inspection processes to monitor safety critical features, or whether insufficient safety factor was allowed for in designing the keel/ hull interface for prolonged exposure to extreme conditions needs yet to be determined.’

Rescuers praised

The families of the missing crew have thanked the public for the ‘overwhelming and unprecedented support’.

In a statement, they said: ‘In the end this petition gained 240,000 signatures. That is equivalent to the population of a city the size of Southampton.

‘This has helped quell our distress somewhat, but in particular Paul, Steve, James and Andrew would have been enormously touched to have known that they were in the minds of so many people.’

Royal Yachting Association (RYA) CEO Sarah Treseder said: ‘Many yachts changed course to sail through the search area and those that were able joined in the search effort. It has been a powerful reflection of the spirit that binds the boating community.’

Fundraising

Former Fastnet crewmates of Andrew Bridge, who raced last year on Cheeki Rafiki and were due to take on this year’s Round Britain and Ireland race with him, will be racing and fundraising in his memory. Their fundraising topped £20,000 for the RNLI in the first 24 hours.

A RNLI Forever by the Sea tribute fund has also been set up by the families of the Cheeki Rafiki crew. Adele Miller, partner of James Male, will be abseiling the Spinnaker Tower in Portsmouth to raise funds, and many other challenges are planned.

Cressida Goslin, wife of Paul Goslin, said: ‘We’ve been overwhelmed with people’s responses to the loss of the Cheeki Rafiki, both during the search and now with people donating so generously. It means a great deal to us and we’d like to say thank you to everyone for their efforts.’

Round Britain and Ireland Race fundraising page: www.justgiving.com/Cheekirafiki

RNLI Tribute Fund: www.rnli.tributefunds.com/fund/Cheeki+Rafiki

CHEEKI RAFIKI TIMELINE

Thursday 15 May 2014 – The crew of Cheeki Rafiki, while returning home from Antigua to Britain, report to yacht agent Stormforce Coaching that
they are taking on water but the situation is stable and they have amended course for the Azores.

Friday 16 May – Contact is lost with the yacht. The US Coast Guard (USCG) begins searching for the four sailors 1,000 miles east of Cape Cod, Massachusetts. Watchstanders from the 1st Coast Guard District command centre in Boston are notified of two406MHz personal locator beacons registered to the 11.9m (39ft) UK-flagged yacht Cheeki Rafiki.

Saturday 17 May – Maersk Kure, a chartered container vessel owned by Costamare in Greece, receives a request from the USCG to assist with the search. Maersk Kure diverts to the area and reports an object which looks like the hull of a sailing boat, but no sign of the sailors. It does not stop. A Maersk Kure spokesman says it is advised to continue the search at another position.

Sunday 18 May – USCG suspends search effort, pending further developments. Maersk Kure says it is advised by the USCG to proceed to its port of destination. Skipper Andrew Bridge’s friend Nicola Evans starts an online petition calling for the USCG to restart the search: this attracts 243,095 signatures. The UK government also sends an official request to the USCG.

Tuesday 20 May – the USCG’s co-ordinated search effort resumes again.

Thursday 22 May – The USCG announces that search operations will be suspended at midnight Friday unless new information suggests the crew are still alive.

Friday 23 May – A US Navy warship helicopter crew locates the overturned hull of Cheeki Rafiki 1,000 miles offshore from Massachusetts. A warship diverts to the location, and a surface swimmer confirms it is Cheeki Rafiki. Underwater photography shows that the liferaft is still aboard the yacht in its storage space, indicating it was not used for emergency purposes. USCG suspends the active search.

Pictures: The upturned Cheeki Rafiki hull photographed by the US Navy; the Cheeki Rafiki yacht; the missing crew members; PBO experts Jim Baerselman, Capt Ed Geary and Vyv Cox