User manual AUTOHELM 1000

[. . . ] Installation and Operating Handbook ANALOGUE Autohelm 1000 The Autohelm 1000 is a highly developed autopilot built to operate reliably in exposed marine conditions. When correctly installed it will soon become a vital crew-member giving many years of invaluable service. The system has been designed for owner installation and aided by the following installation guide, fitting should prove to be a straightforward and enjoyable job. Cockpit and tiller configurations vary widely, and thus in some cases special attachments may be necessary to effect the neatest possible installation. [. . . ] Once the jack plug has been inserted, the connection is absolutely watertight. The wind vane transducer mounting mast is normally clamped centrally to either a vertical or horizontal rail of the after pulpit using the 'U' clamps provided. In the event of an after pulpit not being fitted the mounting flange may be bolted directly to a suitable vertical face. Care must be taken to ensure that the wind vane transducer is in clear wind on both tacks and not too close to the deflected air stream from the mainsail. This is normally ensured by situating the mounting mast centrally behind the backstay and by elevating the wind vane at least 2ft (60cm) above the highest deck obstruction. Feedback linkage The autopilot operates on the principle of mechanical feedback between the sensors and the rudder to correlate corrective rudder action with off course error. To complete installation of the wind vane attachment, the feedback drive cord emerging from the base of the mounting mast must be connected to the pushrod. You will see that when the feedback cord is pulled out of the mounting mast against spring tension, backlash free rotational movement of the wind vane transducer results. Two small blocks are provided for leading the feedback cord to the tiller. Normally only one block is necessary to obtain a clear run out but . occasionally two blocks may be necessary to avoid obstructions such as the mainsheet. The final fairlead should be positioned aft of the actuator unit as shown so that the final run of the feedback cord is orientated nearly at right angles to the tiller. It is important that the final fairlead is positioned below the centreline of the pushrod so that the spring tension on the cord has a tendency to pull the pushrod down onto the tiller pin. Feedback Linkage 9 Finally, a loop is formed on the end of the feedback cord after cutting to length and made fast by means of the plastic adjustor slide provided. The end of the loop is positioned so that the feedback cord is just under tension when attached to the hook on the end of the pushrod in the fully retracted position. This ensures that the feedback cord is under tension over the full stroke of the pushrod. If the feedback cord is over tensioned, the remaining free scope of movement may not be sufficient to accommodate the full stroke of the pushrod and may cause damage to the feedback mechanism at the full extremity of pushrod travel. After adjusting the cord tension as described above, carefully check that the remaining scope of feedback cord movement is sufficient to accommodate the full stroke of the pushrod. After rigging the feedback cord, check that the wind vane transducer head rotates smoothly over the full stroke of pushrod movement. Backlash free vane head movement is essential to ensure accurate steering performance. 10 Operation Functional test procedure Operation under compass control Hold the unit towards the tiller and rotate the compass dial until the cardinal point graduations are approximately aligned with your main steering compass. Switch to calm and note that the north graduation on the compass dial then automatically homes to magnetic north. After completing the installation you should carry out the following functional test to familiarise · yourself with the system before attempting sea trials. The autopilot is fitted with a 4 position thumb · operated rotary switch located on the upper case. The autopilot is switched off when the thumb control wheel is in the fully anti-clockwise position. [. . . ] Alternatively, providing weather helm has not become excessive, the yacht may be trimmed back on to the original heading by re-adjusting the autopilot's compass setting. Vane sensitivity adjustment Normally the wind vane is set almost vertically to operate at near maximum sensitivity. High vane sensitivity is essential to ensure optimum penetration to windward when sailing close-hauled and usually does not result in excessive actuator activity. The sensitivity of the vane may be reduced by tilting the entire unit backwards on its clevis mounting. This has the effect of increasing the 'dead band' of the vane sensor by allowing up to a maximum of 15 degrees course variation to occur before automatic correction is applied. [. . . ]