Grinding out miles even in light winds: we learn how to properly adjust gennaker and Code 0

In the first installment(READ IT HERE) devoted to light winds, we talked about how important mast and sail adjustments are to make the boat make the most of the under these conditions and how proper weight management on board can significantly help our vehicle, even if cruising. In this second in-depth discussion we will discuss light air sails, how to handle them, and more generally how to rig and steer the boat.

The right sail

In light wind sailing, the use of the right sail, which is closely related to the way the boat is carried, is of particular importance. By now, the most popular sail for cruising is definitely the gennaker, if only for the convenience: no boom and sheet, so less maneuvering and an extraordinary ease in making downhauls with a smaller crew. The gennaker, however, is an asymmetrical sail, walled on the bow, or on a bowsprit for those who want higher performance, and then along the longitudinal axis of the boat.

This factor causes part of one’s surface to be covered by that of the mainsail. Many times, perhaps too many times, you claim to sail with the gennaker in the same way as with the spinnaker, and that is one of the biggest mistakes you can make. It is a matter of geometry, the further aft you go, the more the gennaker is covered by the mainsail and therefore the sail does not push at all what it should. Otherwise, with a spinnaker, to go with the most leaning course possible, you could square it by exposing it more to the wind and outside the mainsail cover. Beware, even with the spinnaker, it is not possible to sail extremely leaning in light wind conditions: the boat would slow down too much and even by going less distance our vmg would quickly collapse.

It follows that, with the gennaker, it is necessary to choose an even narrower course with respect to the wind so as to keep one’s speed and consequently one’s vmg high at all times; at the limit one will do a few more gybes but with the gennaker it is much easier.

The importance of the bowsprit

We talked about using a bowsprit, which technically gives us a huge advantage: it moves the gennaker further away from the mainsail cover, and it seems incredible how much a bowsprit that protrudes from the bow even as little as 60/70 centimeters can make the sail more efficient and increase both the speed of the boat and one’s ability to lean. Keep in mind that a well-designed gennaker, allround cruising gennaker, with a shape and weight of fabric that can adapt to almost any wind intensity, can be used from angles starting from about 100 degrees to the wind direction up to even 160/165 degrees and from 3/4 knots of intensity respectively as long as you are good at carrying it in high wind intensities.

Steering the boat with the gennaker is also very important, especially in light winds. We have said that in these conditions the wind direction is very erratic: all the more reason to adjust one’s course to each change in wind direction, precisely to allow the sail to be as exposed as possible and less covered by the mainsail. It might seem that a helmsman who takes a boat with a gennaker in little wind seems to have “upped his game” a little too much because of the snake-like wake he leaves behind but beware, he might also be a very good helmsman. For tighter gaits, from 85 to about 125/130 degrees and 3 to 13/14 knots of intensity respectively, the use of Code “0” is becoming increasingly popular.

The Code 0

This sail was created for use primarily in racing. It is an asymmetrical sail, also tacked on the bow or bowsprit, but with a much flatter shape than that of the gennaker and therefore more suitable for use for tight angles. The same one that is used for the gennaker can be used as the sheet. A special feature of these sails is that they are rollable, so they must be equipped with a whip at the bottom and a swivel at the top; in addition, inside the luff an anti-twist cable must necessarily be fitted, which facilitates sail furling and sail performance in the higher ranges of use. About the anti-twist cable, the advice is to use a good quality one, it affects the boat’s performance quite a lot (the higher the halyard tension, the more efficient the Code “0” is) but also and especially in the greater simplicity in furling the sail. One recommendation: both when opening and especially when furling the Code “0,” do so with very rested gaits; the sail is covered by the mainsail and everything becomes extremely easier.

How to adjust Gennaker and Tails

Is there any special precaution in carrying the gennaker and Code “0”? Definitely yes. To have the greatest efficiency, both of these sails should be carried as loose as possible and almost with a small but constant ear along the top of the luff. Why? The reason is always the same: to keep the sail as exposed and as far from the mainsail cover as possible. Actually this expedient needs to be taken even with the spinnaker but with gennaker and Code “0” even more so; imagine, for example, that 30 centimeters of too much caulked sheet means that 30 cm for the length of the entire luff is covered by the mainsail and if you do the math that can be several square meters less exposure to the wind. It is necessary to use these sails in their optimal range of use; it is useless to sail with a gennaker at 90/95 degrees to the wind direction, just as it is useless to sail at 150 degrees with a Code “0.” They are not sails designed for those gaits, and their efficiency would be irretrievably impaired.

ROBERTO SPATA

Class of 1962 from Como. Laser National until 1983, he then approached offshore sailing by racing on any type of boat and specifically in the IOR, IMS, Maxi Yacht, One-design, ORC and IRC Classes in the roles of tactician, helmsman or mainsman, often taking care of sail and boat tuning.

From 1988 to 2000 he worked with North Sails and continues to have technical relationships and with all the sailmakers, designers and shipyards also as a project manager.