A Naval Biographical Dictionary/Denham, Henry Mangles
DENHAM, F.R.S. (Captain, 1846.)
Henry Mangles Denham assisted in surveying the Channel Islands (Guernsey, Jersey, Alderney, &c.). He acted as Chief Assistant in the survey of the English and St. George’s Channels, from the Straits of Dover to the edge of soundings; of the coast of Ireland from the Shannon to Belfast, including Beerhaven, Crookhaven, Valentia, Baltimore, Glandore, Cove of Cork (entrance), Toughall, Waterford, Carlingford, Strangford, Ardglass, Belfast, Copeland Isles, and Larne; and of the English coast, including Falmouth (Sound), Helford, Manacles (reef), St. Helen’s Pool, Scilly Islands, Skerries, Start Bay, Salcombe, Plymouth Sound, and Dartmouth. He has concluded, too, the survey of the Bristol Channel throughout, including Hartland Quay, Clovelly, Barnstaple Bar, Appledore, Ilfracombe, Minehead, Watchet, Bridgewater, Kingroad off the Avon, Cardiff, Newport, Chepstow, Swansea, the Mumbles, Llanelly, Estuary of Bury, Carmarthen, Tenby, Milford Haven, Solvach, St. Bride’s Bay, and Lundy Island; and of the coasts of Lancashire and Cumberland, with the Dee (to Chester), Liverpool Bay, and the Mersey; Morecombe Bay, including Fleetwood, Lancashire, and Piel a Foudra; and the Duddon and Ravenglass estuaries, Whitehaven, Workington, Harrington, Maryport, and Douglas, Isle of Man. The rank of Commander was conferred on him as a reward for the talent he had displayed in the execution of his surveying services generally, and in particular to mark the high sense entertained by the Lords of the Admiralty of the advantages accruing to the public from the completion of his survey of the port and harbour of Liverpool and the neighbouring coast. The return of the port of Liverpool to the mere capacity of a half-tide harbour Capt. Denham succeeded in averting by harrowing a new opening through the Burbo and Jordan Sands, which, on the accession of Her Majesty to the throne, was named the “Victoria Channel.” In reference to a steam survey made by him in the North Sea, the present Hydrographer of the Admiralty, Sir Fras. Beaufort, declared it to be his conviction “that no man would have achieved that great work with more skill;” and, in remarking upon the survey of Morecombe Bay, the same eminent authority recorded it as his opinion “that a more complete and masterly work had rarely been sent to the Admiralty Office.” In allusion to Capt. Denham’s services in the Avon, on the coast of Africa, whither he had been sent for the express purpose of surveying the Bight of Benin, the Hydrographer thus expresses himself: “In examining a survey made in such a deleterious climate, along such an impracticable coast, and in contact with such a treacherous population, I was prepared to make great allowances for work done under such striking disadvantages; but I find, with equal pleasure and surprise, that the whole has been performed with all the precision and fulness that could have been expected if made under the most favourable circumstances.” For this service Capt. Denham was promoted to Post-rank. Subsequently to his return to England he executed several commissions with reference to the steam marine from the Lords Committee of the Privy Council for Trade, under the conjoint authority of the Board of Admiralty, and also with reference to harbour improvements at Swansea and Bideford. His name continued, as a Supernumerary, on the books of the William and Mary yacht, until the summer of 1847. Capt. Denham has been appointed Inspector of Steam-boat Accidents. He is the inventor of “Denham’s Rowlocks” for rowing boats; and of “Denham’s (registered) Jury-Tiller” for steering a ship on fire abaft, or when twisting her rudder-head, breaking her tiller in a gale of wind, or receiving the enemy’s shot.