asymmetric spinnaker rigging and gybing asymmetric spinnaker
Asymmetrical spinnakers resemble a cross between a large jib and a spinnaker and are now common on sailing dinghies. These spinnakers are set from a long, retractable bowsprits projecting from the bow, replacing the spinnaker pole, making spinnaker handling easier. The bowsprit is constructed from carbon fibre for strength and lightness while the spinnaker is lightweight nylon sailcloth. Asymmetrical spinnaker rigging requires an understanding of the different handling and trimming sailing techniques to an ordinary spinnaker, which is important in knowing how to rig an asymmetrical spinnaker.
An asymmetrical spinnaker is larger than a conventional spinnaker and flown from a point higher on the mast between the hounds and masthead. Asymmetrical spinnaker handling is easier than a conventional spinnaker with the tack remaining attached to the end of the bowsprit and not requiring spinnaker pole adjustment. Asymmetric spinnaker rigging is completed with two sheets attached to the clew which control the spinnaker just like a jib.
Whether an asymmetrical spinnaker is stowed and launched from a chute or pouches depends on the sailing dinghy design. Most bowsprits are normally retracted when the spinnaker is not in use and then extended by the crew prior to the spinnaker being hoisted the helmsman.
Most systems have a single-line which extends the bowsprit while pulling the sail's tack to the outer end at the same time. Some other sailing dinghies have separate lines,with the crew first launching the bowsprit and then pulling the clew to the outer end.
When launching an asymmetric spinnaker, bear away into the hoist/drop zone which is a downwind training run which means that as the sail fills it will not power up, and if the tack is correct, the spinnaker is protected with the main sail.
To handle the spinnaker in the hoist/drop zone, pull up it up quickly being careful as many asymmetrics have a continuous halyard/retrieval line. When pulling on the halyard to hoist the sail, the retrieval line comes back through blocks inside the cockpit, and standing on the rope makes it harder to pull the spinnaker up!
The point of sail that an asymmetric spinnaker flies best on is a reach so once the spinnaker is hoisted then luff up (head up wind) into what is called the power zone, which is from a beam reach to a broad reach.
Asymmetric spinnaker trimming is done using two sheets which lead to the aft quarters of the sailing dinghy and may have twinning lines that move the lead forwards when sailing on a broad reach as displayed in the asymetrical spinnaker setup in the asymmetric spinnaker rigging diagram.
When running, this spinnaker is inefficient requiring sailing downwind to be done in a series of gybes and reaches. The asymetrical spinnaker is trimmed by easing the sheet to keep the luff on the point of curling. Avoid over-sheeting the spinnaker as the ideal asymmetrical spinnaker trim is a slight curl in the luff.
Asymmetrical spinnakers generate considerable lee helm because of the long bowsprit, so be mindful to reduce this by heeling to about 15°.
Avoid sailing too close to windward of other sailing dinghies because when a gust hits, the sailing dinghy bears away and the boat will need space to leeward.
Gybing an asymmetrical spinnaker is uncomplicated as the spinnaker is gybed just like a jib. When the sailing dinghy turns through the gybe, the old sheet is eased fully out allowing the asymmetrical spinnaker to blow around the forestay, and then is sheeted in on the new side therefore completing the gybing motion.