This section describes the rigging of the Xenon Cunningham, Gnav and Outhaul control lines
- There are two control lines that are led back to the port and starboard helm positions with cleats at the rear of the thwart (seat). The bright orange /Black /Yellow control line is the Gnav control. The Black /Grey /Yellow control line is the Cunningham (Downhaul) line. These lines are tied to pulley blocks giving a 2:1 tension. Unfortunately Topper vary the control line colours from time to time. Yours may differ.
- The Gnav control line emerges from the underside of the Boom at the front. Have an assistant hold the boom in its approximate sailing position and attach this line to the small block on the bright orange Gnav control line leading back to the helm position (at the rear of the thwart). When making this attachment ensure that the line is long enough to be without tension with the boom is in the normal position. Make the attachment with a bowline knot.
- Adjust the port and starboard cleats holding the Gnav control line so that equal amounts of line are available and the line is very lightly tensioned.
- The Cunningham / Downhaul line is threaded differently depending upon whether the mainsail is reefed or not. In normal use, ie full sail, thread the Outhaul line straight up through the higher of the two eyelets, sited in the Tack (lower portion of the luff of the main sail) from port to starboard. Then down and through the hole in the gooseneck from starboard back to port and then up to the lower cringle (sail eyelet) where it should be tied off. Now pull down on the tied off line and ease it back through the gooseneck hole until the lower cringle is under tension. The purpose of putting the lower cringle under tension is to ensure the slug in the bottom of the mast track does not ride up and come free whilst sailing. This does not affect the downhaul tension applied to the second cringle.
- Adjust the port and starboard cleats holding the downhaul line so that equal amounts of line are available and the line is very lightly tensioned.
- In use the Gnav control line has a profound effect on the performance of the mainsail. If the Gnav control is only lightly tensioned the top section of the sail will twist open. To observe this view the Xenon directly from the rear when sailing away. If the Gnav control is then pulled in hard (quite a bit of tension is needed) you can observe the top of the mainsail straightening, the twist will completely disappear and the Xenon will develop full power.
- The Outhaul line should be rigged at the same time as the mainsail slug is slotted into the boom track. The Outhaul should be lightly adjusted to prevent the slug from being pulled forward and out of the track as the mainsail is being hoisted, but it should not be over tensioned otherwise it will not be possible to pull the mainsail to the top of the mast. the photo below shows how the Outhaul line is rigged.

Outhaul Line viewed from below the rear of the boom.
The Outhaul line is fed from the boom (left side as shown in the photo), up through the clew of the mainsail and then loops back over the right hand boom sheave as shown in the diagram. A small overhand knot is used to lock the line.

View of Outhaul line looped through the mainsail clew cringle.
The Outhaul is finally tensioned only after the mainsail has been fully hoisted.