Asymmetrics, chutes and gennekers

Asymmetric spinnakers, cruising chutes and gennekers are basically one and the same.

They are similar to symmetrical spinnakers in that they are light, colourful sails generally flown when the wind is on or aft of the beam, but that is where the similarity ends. The sail shape resembles a baggy loose luffed genoa and has a permanent luff, tack and clew. If a pole is required it is usually a small one in the form of a bowsprit.

Equipment

Spinnaker halyard - led from a block fixed above the forestay.
Two sheets - each about 2.5 times the length of the boat with snap-shackles attached.
Two swivel blocks - attached to each quarter.
Tack line - usually led from the bow to the cockpit. This is often adjusted to change the shape of the sail or help gybing. Swivel block at the stem-head or a bowsprit for the tack-line.

Set up

The sail flies outside of the boat and so all lines should be rigged and led outside the shrouds, forestay and stanchions. The spinnaker bag is attached to the leeward guardrail behind the genoa. Lead the tack line from the cockpit through a block on the bow, or through the bowsprit, and attach it to the tack.

Lead the sheets from the clew, outside everything, to a block on each quarter, then to a winch. Ensure the windward sheet is led outside of the forestay. Lead the halyard to leeward of the genoa and attach to the head of the spinnaker.

Hoist

Head onto a broad reach so the main and headsail shelter the sail as it is hoisted. Adjust the tack-line until the tack is about 1m from the stem head block or bowsprit. Secure the tack line.

Put a couple of turns around the winch of the leeward sheet, leaving plenty of slack. Quickly hoist the halyard to the top of the mast, pull in on the sheet as the sail starts to fill, then furl the genoa away.

Trimming

Using the tack line, the luff can be tightened when close to the wind and eased when off the wind. Ease the sheet until the luff starts to curl, then tighten until it stops curling. If the spinnaker is over trimmed the boat sails slower and weather helm will increase. Check by easing the sheet.

To sail on a reach pull in the tack-line to straighten the luff and sheet in.

To sail further off from the wind, ease the tack-line and sheet allowing the sail to move in front of the boat providing more forward drive and less heel.

Tactics

Asymmetrics get shielded by the mainsail when running downwind so the preferred tactic is to broad reach and sail downwind in a series of gybes. Whilst the course is longer, the speed is higher and both mainsail and asymmetric work efficiently.

Gybing

Gybing an asymmetric is very straightforward. Head onto a broad reach.
Ease the tack-line to give greater space between the luff of the asymmetric and the forestay.
Take up the slack on the new sheet and ease the old sheet to pull the clew through the gap between the forestay and the tack line.
Gybe the main and trim the new spinnaker sheet accordingly.

Dropping

Bear away on to a broad reach.
Unfurl the genoa to reduce power in the spinnaker.
Take hold of the lazy sheet from under the boom and gather the spinnaker as the halyard is eased.
Stuff the sail down below deck through the companionway hatch.