DETAILED DESCRIPTION 473 



between the water-tunnel part of the casting and the outer-wall part is filled with sufficient lead to 

 bring the centre of balance of the machine forward to the required point (p. 477) (Figs. 3-5). 



B. The box-like central section is built up on a frame of \ r x J x J in. angle phosphor bronze 

 connecting the corners of the rectangular parts of the castings A and C. It is covered on the top, 

 bottom and right-hand side by plates of iV-in. sheet brass ; on the left-hand side are doors of the same 

 material hinged at the sides, meeting in the middle and opening to allow the removal of the internal 

 mechanism (Figs. 3, 4). 



G. The rear or tail section is a tapering casting the front end of which is rectangular and forms 

 the rear end of the central box section B. This rectangular part of the casting is closed except for an 

 aperture 4 by 1 \ in. Formed on the casting in front of this aperture is a housing machined to take 

 the rear end of the water tunnel of the internal mechanism and forming an exit for the water. Behind 

 the rectangular front part the casting forms top and side walls for the tapering part which is open 

 below. A horizontal deflector plate CA is fitted level with the top of the water-tunnel exit. Lugs 

 CB, CB' are formed on either side of the casting to carry the horizontal tail fin (Figs. 3, 4). 



D. The towing eye of phosphor bronze, secured to the front section casting A by seven j^-in. 

 steel bolts and nuts. The opening of the eye is § in. internal diameter and its centre is if in. above the 

 top surface of the central box section B and 7 in. behind the front of the machine (without the nose 

 cap) (Figs. 3-5). 



E, E'. Cast phosphor bronze brackets securing the diving plane F to the body. Each is secured to 

 the casting A by three § in. steel bolts and nuts and to the plane by one \ in. steel bolt and nut 

 (Figs. 3-5). 



F. The curved diving plane of J-in. steel having a span of 19^ in., a width (chord) of 6 in. and 

 an angle of incidence of 12J- (to the fore and aft axis of the machine). The leading edge is z\ in- 

 below the front end of section B, and the rear edge 1 in. below the bottom surface of B. It is im- 

 portant to note that this plane is placed very slightly asymmetrically in that it extends 9^ in. from 

 the centre line to the right and 9^ in. from the centre line to the left. This asymmetry gives a slightly 

 different downward pressure on the two sides and counteracts the slight asymmetrical weighting of 

 the machine due to the internal mechanism not being quite balanced about the central line but 

 placed slightly to the left to accommodate the train of gear wheels on its right-hand side 

 (Figs. 3-5). 



G, H. The two sections of the vertical tail fin made of iV m - steel plate. They are separated to 

 accommodate the propeller shaft O which passes between them and are held together in front by 

 the castings I and /', and behind by casting J (Figs. 3-5). 



I, I'. Castings securing the fin plates G and H, forming a tunnel opening through which the 

 propeller shaft O passes and base plates which are each secured to the casting C by two J-in. bolts 

 passing through transverse slots. These slots in the castings / and /' allow, if necessary, an adjust- 

 ment of the fin to act as a set rudder to counteract any tendency of the machine to go to 

 port or starboard. This adjustment is only used when the correction afforded by the biasing rudder L 

 is insufficient (Figs. 3, 4). 



J. Casting securing the fin plates G and H behind and forming the housing for the bearing O 

 for the propeller shaft. This is secured to the machined top surface of the casting C by three j-in. 

 studs. At the top a boss is formed for accommodating the bolts securing its guards M and N 

 (Figs. 3, 4). 



K. Horizontal tail fin of J-in. brass plate, secured by three 3^-in. bolts on either side to lugs CB 

 projecting from the casting C (Figs. 3-5). 



L. Biasing rudder inset in vertical fin G, to which it is hinged in front. Its rear edge is furnished 

 with a toothed rack LA which allows it to be set in any desired position and locked by the slotted 

 plates LB, LB' (Figs. 3-5). 



M. Guard ring round propeller, secured above to casting/ and below on each side to the tail fin K 

 at MK (Figs. 3-5). 



