The islands of Bigga, Brother Isle, Lamba, Orfasay, Little Roe, Samphrey and Uynarey lie in this part of the channel.

Sullom Voe terminates at the extraordinary Mavis Grind, a narrow isthmus separating the North Sea from the Atlantic Ocean.

These boats have a registered tonnage in excess of six times that of the ships they replaced on the route and their increased size has significantly improved transport to the northern isles.

Originally the service called at numerous small villages in the sound, but after 1932 the stopping-off points were reduced in number due to competition.

Weighing 548 tons and with a length of 47.2 metres (155 ft), the ship was popular with summer visitors but cargo was handled by a single derrick and a government subsidy of £100,000 per annum was required to support the operation.

[6][7] In addition to the weather conditions, sailing vessels have to contend with strong currents and numerous shipwrecks and hazardous incidents have occurred in and around the sound.

In June 1914 the 50.2 metres (165 ft) steamer Robert Lea was grounded on Stoura Baa at the north end of Brother Isle en route from Colla Firth to Liverpool also without loss of life.

The 22 metres (72 ft) fishing boat Morning Star sank approximately 1.5 kilometres (0.93 mi) north west of Muckle Holm lighthouse whilst under tow after a fire broke out in the engine room.

In 1983, the Royal Navy cleared ordnance from Little Holm, and their bomb disposal team discovered an unrecorded shipwreck nearby.

To the north Bagi Stack Lighthouse on Yell to the east, and Gruney and Point of Fethaland to the west are the outer lights.

[17] The profusion of seaweeds including wrack (Fucus serratus) and tangle (Laminaria digitata) was briefly exploited for commercial purposes.

[18] Away from the beaches, Yell Sound is little used for recreational purposes, possibly due to the relatively high volume of tonnage accessing Sullom Voe.

The low-lying peaty coastlines provide easy access to fresh water, extensive algal beds in the marine environment and large numbers of otter holts.

[21] Sullom Voe is a separate SAC, qualifying due to the numerous large shallow inlets and bays, coastal reefs and lagoons.