There’s nothing quite like surfing off a wave in the open ocean, spinnaker straining and helm vibrating under your fingertips. For me it’s sailing at its best.

In this article and the accompanying video with Brian Thompson I look at a few ways to maximise that feeling, making the most of your miles under spinnaker and finding the right balance between comfort and speed.

See our video of SAIL FASTER SAIL SAFER Part 9

Asymmetric

With all spinnakers make sure the sail is fully hoisted on the halyard. A great way to get this right every time is to mark the halyard at full hoist just by your rope clutch. If you are using a snuffer, double check the bucket is hoisted high enough to expose the head of the spinnaker underneath.

The tackline on an asymmetric spinnaker controls the volume in the luff, but also allows the sail to rotate to windward.

Let the tackline off to give a fuller, more powerful shape and to allow the sail to rotate to windward when going deep downwind; as the breeze increases or you come up to a reaching course, pull on the tackline to make the sail more stable and stop the luff from falling down to leeward.

To find an initial setting for the tackline, pull it on until a crease forms in the luff, then gently ease it back out until the crease has just disappeared.

For maximum speed the sheet will be played constantly, to ensure that the luff of the spinnaker is always curling. However, if you are short-handed or looking for a more peaceful passage, over-trim the sheet a little and lock it off.

Luff telltales can help enormously with setting an asymmetric spinnaker, both with trimming your sheet, but also with positioning the tweakers to change the sheeting angle.

The tweakers on an asymmetric work rather like the jib cars on a headsail; pull them on to bring the clew down and stop the sail from rotating too far to windward, but let them off when reaching.

Keep the luff curling:

Symmetrical kite

Setting the pole correctly is a good place to start with symmetrical spinnaker trim. As a rule of thumb, the outboard end of the pole should be set at a height that will keep the two clews of the spinnaker level. Where possible set to make sure the pole is horizontal to project the spinnaker as far outboard as possible.

Remember that raising and lowering the pole will also have an effect on the shape; a higher pole gives a fuller, rounded shape, with a centre of effort further up the mast.

In breezier conditions, or when reaching, move the pole down the mast to flatten out the head of the sail, making it less powerful, but more stable.

Once your pole height is established, set the pole angle at about 90° to the apparent wind. Aim to have the luff of the spinnaker flying vertically above the pole; if the luff falls to leeward, let the pole forward, if it rolls to windward bring the pole back.

As you steer the boat further downwind, keep bringing the pole back to get the spinnaker out from behind the mainsail.

When passagemaking most of us are prepared to sacrifice a little speed for a more relaxed sailing mode so, to make life easier, set up the pole to optimum position and then ease it forward by about a foot. This will give a poorer performance, but will allow for small variations in the wind direction without requiring a retrim.

When sailing deep downwind with the pole squared right back, easing the spinnaker sheet will allow the leeward clew to lift and the leech of the sail to twist open. Pull on the tweaker and move the sheeting angle further forward and this will gently pull the clews level again. When reaching don’t forget to let the tweaker right off.

In bigger breeze or rolly conditions pull the tweaker on even more to keep the sail stable; this will take some of the power out of the sail and should make it more manageable.

On longer passages use the tweaker to keep the sheet from chafing on the bottom of the boom.

Keep the clews level:

Mainsail

Don’t forget your mainsail when sailing downwind. Drop the traveller all the way to leeward and let the boom out until you get a bubbling in the front of the main.
It is fine for the sail to rest against the spreaders, but if you are planning on making long voyages downwind it is wise to put extra wear patches in these areas.

Use the kicker to adjust leech tension, using the leech telltales as a guide; make sure they are streaming out behind the sail; too much kicker and the top ones will stall.

Don’t forget to ease the outhaul, halyard tension and backstay to maximise downwind power from the main.

Steering

In lighter winds it is all about keeping the boat moving. Lock off the spinnaker sheet and steer the boat to keep the sail full, watching the luff, and sail steering to telltales or making sure the luff stays curling over, but not collapsing.

The autopilot will work best in moderate airs downwind – as always, to save battery hours adjust your pilot settings and your sail trim for the conditions to ensure the pilot is on the lowest response or gain setting possible. As a guide, make sure your pilot is not working harder than you would if you were on the helm.

In stronger breeze or greater swell it can become harder to steer both for you and the pilot. If the boat is rolling a lot try depowering the spinnaker by easing the pole forward, pulling on the tweaker and over-sheeting the sail a little, then steer a couple of degrees higher.

Most modern autopilots are able to steer to True Wind Mode. If you have a machine that can do this, it is by far the best mode to use when sailing downwind in bigger breeze. If this is not possible then steer the boat to a compass course, but the sails must be trimmed to allow for a change in the apparent wind direction as the boat surfs down waves.

Top tip: night sailing

• Chevrons on the luff of the sail with reflective tape will help when you’re trimming at night time

• White spinnakers are easier to trim in the dark

• Allow for small alterations in course by easing the spinnaker pole forward and over-trimming the sheet a little

• Before it gets dark mark your guy and sheet position with a piece of tape on each rope; that way if you have to make a short-term alteration it will be easy to find your base settings again.

Do’s and don’ts

• DO be ready for a quick drop, especially during the night
• DO use a preventer to keep the boom out of the cockpit if there is a lot of swell
• DO check the guy for chafe through the pole end on longer passages
  (a protective jacket is a good idea)
• DON’T set and forget; check your spinnaker pole angle regularly and bring it back when you can
• DON’T let your autopilot work too hard. If it’s going lock to lock there is something wrong; change your trim

Single-handed ocean sailor Pip Hare has clocked up thousands of miles racing and cruising. Among her achievements are five solo transatlantics, including the OSTAR and two Mini Transat races. She also works full-time for the RNLI on sea safety and is Consulting Editor on Yachting World. See also her series on short-handed sailing

Brian Thompson is a vastly experienced sailor, who has raced solo and fully crewed round the world in monohulls and multihulls. His most recent record-breaking run was with Loïck Peyon aboard the trimaran Banque Populaire V, which sailed round the world in a breathtaking 43 days

SAIL FASTER SAIL SAFER Part 10: Pip Hare looks at hoisting a spinnaker with and without snuffer

SEE ALL 12 PARTS HERE

12 part series in association with Pantaenius