=(0.63B-A) C.B. Vr 2 71460 Page 20 Steering systems, rudders and stocks Cylinder dimensions (mm) and Torque (Kg-Met) The Helm Pump Smooth operating, high efficiency axial piston pumps provide the 'Power' to the steering cylinder when the steering wheel is turned. They are matched to cylinder size to give suitable number of wheel turns according to the rudder torque. All helm have a lockvalve which 'blocks' rudder feedback and isolates each pump in a multiple station. The system is filled simply by pouring the recommended oil into the helm pump filler - no external pressurisation is required. Any number of steering stations may be used in a single system. Each helm pump operates independently without station transfer and each has full control of rudder. Wheels not in use do not turn. Optional power steering and autopilot pump sets are connected in the same manner as additional stations. Helm, Cc/Rev 20 25 to 45 68 HL Total Length 228 215 314 BL Body Length 108.5 107 90 SL Shaft Length 62.5 55 97.5 HD Body Dia 127 115 142 Cylinder, Bore X Stroke 32 X 178 40 X 178 40 X 222 50 X 230 50 X 300 Cc for Full Stroke 132 168 215 339 442 Max Torque Kg/Met 58 87 111 217 281 A Overall length 568 620 720 901 981 B Max sideways Projection 151 175 225 265 335 C Cylinder and mount length 348 366 416 500 570 D Base Width 60 60 60 90 90 Hydraulic steering Helm head dimensions Lancing Marine standard rudder dimensions (cms) Rudder and tube assembly Lock valve at each steering station High overall efficiency All components repairable Ideal for multi stations and autopilot No pressurisation required Suitable for most boats 4m to 20m Speclal attachments available for Sternpowr 80, Mercruiser, Autopilot and through tube outboards Rudder torque must be carefully calculated as follows:- Torque forward (Kg-Met) =(0.37B-A) C.B. Vf 2 71460 Torque astern (Kg-Met) A = Balance length, cms B = Total length, cms C = Rudder height, cms Vf = Max. forward speed, knots Vr = Max. astern speed, knots Detailed calculations can be done using the Lancing Marine Boatspeed and Propeller Program, available for PC operating systems. A cm B cm C cm SD ins SL cm MAX kts @ 30° 8 20 30 1 20 25 10 25 38 1 25 18 10 25 38 1¼ 23 25 12 30 46 1¼ 23 18 12 30 46 1½ 25 25 15 38 56 1½ 25 18 15 38 56 1¾ 28 27 15 38 56 2 30 28 HD Helm LD Helm The Steering Cylinder Cylinders are double acting, fully balanced, to give an equal number of turns of the wheel in each direction. Suitable end fittings are provided, according to application, but usually a ball joint on the end of the rod, and a swivel base on the cylinder. 32mm and 40mm cylinders have aluminium bodies and larger cylinders all have brass bodies. Compression fittings and nylon or metallic piping complete the kits.