Boyle Somerville was born at
Castletownshend, County Cork. His father was Thomas Henry Somerville and his mother was Adelaide Eliza Coghill. Somerville joined the
Royal Navy as a cadet in 1877. His first service was in South America in 1880, and then in the
Anglo-Egyptian War in 1882. He then spent four years on the China Station. He trained as a
Hydrographic Surveyor, choosing this branch of the Navy because promotion prospects were good, and because it offered opportunities for a much freer existence than the "intolerable uniformity" that he saw as typical of much Navy life. As a lieutenant, Somerville worked on the surveys of the
Queensland coast and the New Hebrides, now
Vanuatu, in the South Pacific, (, 1890–91). While in Vanuatu he carried out
ethnographical work, which was published in 1894. In 1893–94 he was surveying in the South Pacific with . Sounding in the
Kermadec Trench between
New Zealand and
Tonga, they found a depth of , the greatest ocean depth ever found up to that time. They then surveyed
New Georgia in the
Solomon Islands, also with
Penguin, and Somerville published an account of the islands and its peoples. He built a significant collection of ethnographic artefacts from the Solomon Islands which is now in the
Pitt Rivers Museum, Oxford. The collection includes personal ornaments, canoe carvings and some of the tools used to make them, and fishing implements.
Henry Balfour, curator of the museum, wrote an article in 1905 discussing bird and human designs in the Solomon Islands, making use of material collected by Somerville. In 1897, Somerville joined working mostly in British Columbia, but with some surveying in western South America and the Pacific. In 1899,
Egeria carried out soundings for a proposed telegraph cable in the north Pacific between
Vancouver and
Hawaii. 166 soundings were carried out in depths up to . Somerville wrote the report of the sounding cruise. In 1900 he joined spending two seasons in home waters. He was promoted to
commander on 31 December 1901, and the following year was posted to the
Hydrographic Department for temporary service. In 1902 he carried out a tidal survey of the channel Islands, and he surveyed in the
Persian Gulf in 1902–03.(), His brief included evaluating potential enemy naval bases on the Persian shore. He surveyed in Ceylon and the Indian Ocean between 1904 and 1907 with . From 1908 to 1914 he surveyed British coastal waters in . Shortly before the
First World War, Somerville developed a steam-operated sounding machine for determining ocean depth from a ship that was under way. In 1908, while surveying in British waters, Somerville read a book suggesting
stone circles and
standing stones might have astronomical significance. He thereafter devoted much of his time to surveying and in some cases excavating, such monuments in Britain, Ireland and elsewhere, and became a recognised expert in the field of
archaeoastronomy. Among the sites he described were the
Drombeg stone circle in County Cork, a group of monuments near
Lough Swilly in County Donegal, and the
Callanish standing stones in the Outer Hebrides. A modern overview of his work has been provided by Lacey (2008) During the First World War Somerville served in the North Atlantic Patrol from 1914 to 1916, commanding
HMS Victorian, , and . Operations were based around
Madeira, the
Canary Islands, the
Azores and the
Cape Verde Islands. With no safe harbours in these islands the ships were always at sea during the night, taking on coal only during daylight hours, to reduce the risk of submarine attacks. This led to one spell of 385 consecutive nights at sea during 1915 to 1916. Somerville was involved in the "diplomacy of force" with the Spanish authorities to prevent violations of neutrality, both regarding use of radio communications and port facilities by the Germans. In October 1914 this led to the internment in
La Palma of the
Macedonia, a neutral-flagged vessel believed to be provisioning the German commerce-raider . In 1917 he was based in
Halifax, Nova Scotia, commanding on Atlantic convoy support. As part of the late summer 1917 reorganisation of the burgeoning British
Secret Intelligence Service, led by
Mansfield Smith-Cumming and his de facto deputy, Colonel Freddie Browning, Somerville was appointed as "officer in charge of the Naval Section within the Secret Service Bureau". This was the first career naval officer posting to the Secret Service. In February 1919, Somerville wrote a review setting out a number of basic principles for service and encouraging the development of specialist intelligence technical skills within the navy for intelligence gathering and analysis. Also in February 1919, he was appointed a
Companion of the Order of St Michael and St George "in recognition of valuable services during the war". ==Retirement and death==