Dodging the Scilly Rocks - or Not

The Isles of Scilly have claimed many ships over the centuries - the most famous disaster was in 1707 when four Royal Navy warships, commanded by the splendidly-named Sir Cloudesley Shovel, misjudged their position after days at sea returning from the Bay of Biscay. They all foundered on the unlit rocks and about 2000 sailors perished - an event which drove the journey towards better navigation systems, including the availability of accurate timepieces to allow for the accurate calculation of longitude for ships on extended voyages.

Even today, with all our GPS technology, navigation around the islands has to be taken very seriously. The tidal range covers boat-breaking rocks with seemingly tranquil waters, while currents surge around the islands making it very easy for a boat to be swept sideways into danger.

We decided on a challenging little passage from Bryher, around the top of neighbouring Tresco and down through Old Grimsby Sound.

The green areas dry at low tide so we crossed on a rising tide with about a metre of water under our keel

A chicane to avoid the Cones

Most people these days rely on chart plotters and digital charts but we carry detailed paper charts for the islands and they carry the following warning, so it's vital to look through the clear water to confirm the position of any charted dangers:

Sadly for a Swedish couple, this warning was unheeded. Once we'd arrived safely in St Mary's we saw the Lifeboat bringing their sinking 40ft yacht into the harbour, with emergency pumps running to keep her afloat.

The official report suggested that they'd struck an isolated rock off the north coast of St Martin's and had damaged their propeller saildrive, causing a significant ingress of water. The lifeboat coxswain had to carry out a risk assessment as they arrived on scene; the RNLI's primary concern is to save lives at sea so they evacuated the yacht's crew and put two of the lifeboat's crew onto the deck, with a petrol-powered salvage pump. For a while they weren't sure that the pump would keep up with the in-flooding but they were clearly keen not to have the yacht founder (with risks of pollution and navigation dangers to other water users) so were relieved to keep the yacht afloat. The fire brigade added their emergency pump as soon as the yacht came alongside in St Mary's and the Lifeboat carefully put the casualty vessel alongside the old quay to dry out at low tide.

The poor Swedish crew now face a huge set of challenges, starting with emergency hull repairs to keep the water out as the high tide refloated the boat. After that there would be the tasks of finding a permanent fix to the hull, plus the unenviable job of cleaning and drying the boat out. After such a catastrophic event, damage to engine, electrics, batteries and woodwork would all need professional assessment and repair. No wonder they looked profoundly shocked  - we offered to get them a tea and the skipper was still in disbelief - "We were in 20m of water, had just checked the chart and then there was a terrible bang", he said.