Asymmetrical spinnakers resemble a cross between a large jib and a spinnaker and are now common on sailing dinghies. Asymmetrical 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.
An asymmetrical spinnaker is larger than a conventional spinnaker and flown from a point higher on the mast between the hounds and masthead. 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. Attached to the clew are two sheets 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.
Once in the hoist/drop zone, pull up the spinnaker 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.
An asymmetrical spinnaker is trimmed 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.
When running, an asymmetrical spinnaker is inefficient requiring sailing downwind to be done in a series of gybes and reaches. The spinnaker is trimmed by easing the sheet to keep the luff on the point of curling. Avoid over-sheeting the spinnaker as the ideal 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 is uncomplicated as an asymmetrical spinnaker is gybed just like a jib. When the sailing dinghy turns through the gybe, the old sheet is eased fully out allowing the spinnaker to blow around the forestay, and then is sheeted in on the new side.