H. M. Steam Vessel Virago, 1841—1843. 1845, 1846

Steam Boat Engines (75 items).

1230. H. M. Steam Vessel Virago (KP & KQ). May 1841-Apr. 1842, Jul., Oct. 1842, Nov. 1843; Feb., Jun. 1845, Mar. 1846. 75 items.
Two 150 horse power direct-acting "Gorgon-type" boat engines, with 64¾ inch cylinders, 5 foot strokes.

Sheet of tracings of sections and plan of the engine room, made at the Admiralty and signed by William Symonds; cross-section of the boat and engines - coloured reverse drawing made in the London office; plan of the engine room and boiler etc., longitudinal section of the engine room and boiler - coloured original and coloured reverse drawings made in the London office and given letter codes.
Sections and plan of boiler - coloured reverse drawing made in the London office; slide valve, cylinder and slide valve - partially coloured original and partially coloured reverse drawings made in the London office; condensers etc. - partially coloured original and partially coloured reverse drawings; foundation plate for the cylinder, cylinder bottom - shaded drawings; paddle wheel and shaft - original and reverse drawings made in the London office; lower headstock column - coloured drawing; upper headstock column; scheme for disengaging apparatus and eccentric gear - coloured drawing made in the London office; headstock frame - original and direct copy made in Jun. 1845; conical valves - coloured drawing; engine shaft, cylinder cross bar guides and bracings - partially shaded original and partially shaded reverse drawings; feeding pipes etc., section of hot water cistern (made in the London office) - partially coloured original and partially coloured reverse drawings; air pump beam and cross bar guides - original and reverse drawings made in the London office; connecting rod and cross bar - partially coloured original and partially coloured reverse drawings; views of the headstock frame - coloured original and coloured reverse drawings; section of air pump and condenser - coloured original and coloured reverse drawings made in the London office; connecting rod and cross bar for working the air pump - 2 partially coloured reverse drawings; coal boxes - partially shaded reverse drawings; side view of feed and bilge pumps - original and reverse drawings made in the London office; end view of hand and bilge pumps - original and coloured reverse drawings made in the London office; valve box for the hot water pumps - partially coloured original, partially coloured direct copy and partially coloured reverse drawings; safety valves - coloured original and coloured reverse drawings; working gear - partially shaded drawing; eccentric rod - coloured original and coloured reverse drawings (mis-dated as 1840). Most of these drawings bear letter codes.
Also the following uncoded items, rough drawings, memoranda etc.: press copy specification; memorandum of work to be done in Jan. 1842; press copy plan and side view of the engines; press copy sketch of piston rod cross bar; 2 drawings of pistons and packing ring; transcript of letter from James Brown to Henry Wollaston Blake dated London, 10 Oct. 1842; rough tracing of coal boxes [?]; sketch of piston rod; press copy sketch of positions of bolt holes in sides of upper headstock frames; sketch of block and lever for working gear (with press copy); sketch of part of valve [?].
Also the following later items: section through lower nozzle and condenser and drawings of air pump and buckets (3 pencil drawings on 1 sheet, not dated); section and plan of stay bolts - partially coloured drawing taken from sketch by John Boswell, Nov. 1843; proposed additional waste water pipes - 2 coloured drawings signed by Commander G. S. Otway and John Boswell, Chief Engineer (not dated, circa Feb. 1845), additional waste water pipes - partially coloured original and partially coloured reverse drawings, Feb. 1845 (these drawings bear letter codes); plan of beam for working air pumps, signed by Commander G. S. Otway and John Boswell, 1st Engineer, with tracing taken from it, Mar. 1846.

Original Portfolio or 'Book' No. 935. Catalogue of Old Engines p. 322.

For H. M. Navy. This was the first set of "Gorgon"-type engines that Boulton Watt & Co. built. Virago was broken up in 1876.

See also: Portfolios 5/1280g, 5/1280h, 6/29 (general drawings of 150 horse direct engines).