In the latest issue of Australian Sailing magazine, sailmaker and columnist Tony Bull looks at spinnaker handling techniques, and provides lots of tips to help readers improve their boats' downwind performance and eliminate (or at least reduce) the white-knuckle element of gybing.
Tony, who runs the Bull Sails loft in Geelong, writes:
The word 'spinnaker' is probably the cause of the most angst among club level and beginning sailors. We have all seen a myriad of pictures and videos of yachts wiping out in sensational style and they are nearly always under spinnaker when it happens.
All yachties have a vast collection of 'spinnaker stories'!
Two traits make the spinnaker a handful. Firstly, there is the sheer amount of sail area that this sail adds to a yacht's sailplan. It is not unusual for a spinnaker to be up to twice the size of the combined total of the mainsail and headsail, so it adds a great deal of horsepower.
Secondly, the spinnaker is a free-flying sail, connected to the boat only via the spinnaker pole which is a temporary appendage to the rig. It is not tacked down to the boat like all the other sails, and so can have the ability to “get away” and stream a distance from the hull, making it hard to recover when things go wrong.
Using a symmetric spinnaker rather than an asymmetric one can have advantages on the racetrack. This is definitely preferential for a lot of medium to small displacement-style hulls, which have no one fixed mode to sail downwind; as the conditions vary so does the angle required to keep them sailing at their peak.
In a high performance, lightweight planing hull an increase in the breeze strength will see the apparent wind go forward as the boat speed increases and as a result the boat can sail lower angles. But on a heavier, more traditional hull that does not have such great velocity variations, it is beneficial to be able to bring the pole back and sail deeper in a gust, then ease it forward to sail a little higher in a lull.
Another area where the symmetric spinnaker is a huge advantage is on the modern windward/leeward course where the runs are dead square and particularly when the legs are short, the ability to sail low and cover less distance is a fortunate thing. Boats with asymmetrics have to sail a hot angle to build up their speed, then have to gybe (often several times) to get down to the leeward mark, collapsing their spinnaker and having to restart the speed build all over again each time. Meanwhile the boat with a conventional spinnaker can simply run low, gybing without having to collapse the chute and thus experiencing no loss of momentum.
Also on these courses, in particular those with a gate at the bottom, the asymmetrical spinnaker can provide more tactical options, such as a quick gybe-set rounding the top mark which allows the boat to be squared up and preventing competitors from gaining an inside overlap.
Approaching the bottom mark or gate with an asymmetrical spinnaker can be tough trying to pick the best angle, as it varies so much with breeze fluctuations and you are quite often constrained and forced to compromise your rounding, on a symmetric boat however anything is possible if you are a little overlaid on the mark then square pole back to run deep, remove the pole early and floating the spinnaker for the last four to five boat lengths means you can drop either side or round either side of the gate.
The main point to remember is that when we gybe a symmetrical spinnaker, the sails basically remains flying in the wind and we turn the boat underneath it. It is imperative to try and keep the spinnaker flying all the way through a gybe. This should be a job for your best trimmer.
It is crucial to get the spinnaker out in front of the forestay so when the boat turns, the forestay passes behind the chute and does not hook it up. I often find it is very hard to get trimmers to ease the sheets and fly the spinnaker out in front like this, because as the pole is unhooked there is a natural tendency to want to pull the spinnaker in close to stop it getting away.
As is always the case, sailing fast is a combination of sail trim and steering working in concert. The helmsman or woman needs to watch the spinnaker as closely as possible, helping the trimmer to keep it flying. Slowing the boat's turn a little if the sail luff is curling, or heating up a little if the sail gets shivery can help the trimmer and enhance the gybe.
For more of Tony Bull's great advice of both end-for-end and dip-pole gybes, and suggestions for spinnaker training drills which will help perfect your crew work, see the Persistent Shift column in the June/July issue of Australian Sailing magazine, on sale now.