Self-tacking headsails or changing direction made easy

Self-tacking headsails make sailing short-handed a breeze, explains AY contributor, Ralph Skelton.

Wouldn’t it be nice if you could making a tack in a crowded harbour without the hassle of letting one jib sheet go and bringing the other one on?   Or perhaps you’ve wanted to go for a sail, but couldn’t find anyone to go with so you put it off.

There is something that can help you in both of these situations, a self tacking jib.   Solings, 18 footers, 5.5’s and many other classes, all race very successfully with self tacking jibs. 

Yes, there are compromises to be made.   The most significant is that only jibs less than 100% of the foretriangle can be made to self tack successfully.  The next compromise is that on most self tacking systems, roller reefing is not terribly successful, but more on this later.

Generally speaking, retrofitting of self tacking jibs requires careful planning, the most obvious consideration is that if you have a yacht with an overlapping jib, then the mainsail is sized on that assumption.   So if we reduce the size of our jib to make our boat self tacking, we will move the centre of pressure of our rig aft, and so increase our weather helm. So retrofitting a self-tacking jib should be done in consultation with a naval architect and sailmaker.

Commonly, there are three systems of self tacking jibs, they are illustrated in diagrams 1, 2 and 3.

Ideally, the track on which the jib sheet car runs should be curved in both horizontal and vertical planes.  These curves are made so that the clew of the jib remains nearly a constant distance from the track as it moves from side to side.

There are however, other variations on this theme.  International Fourteens, for instance, sometimes use a gentle W shaped track to get the clew far enough aft while the track goes forward of the mast.

For most self tacking jib systems, the jib has a clew plate built into it with different sheet attachment positions. This allows for altering the sheet angles at different wind strengths, because unlike non self tacking jibs, the sheet turning position cannot be moved fore and aft.

Not shown in the diagrams is any way of restricting the position of the car on the track.  There are a few versions of this.  One is to run a line from the car to the centre of the boat near the track.   This system is clearly shown on the accompanying photo of a 5.5. deck layout and a slight variation where the additional purchase appears on deck in the pictures of the Seawind 1250 (top next page).  This line goes via some additional purchases as necessary to a cleat and by varying its length, the car position can be varied.  Another version is to put positive stops, either permanent or movable, on the track and allow the traveller car to move along them as the yacht tacks.

Notice that it is essential that the track must be securely fitted to the deck, as it has considerable stress placed upon it.

Systems without a jib boom can accommodate a small amount of roller reefing, particularly if a device such as a MACLEW is used on the clew to maintain the correct sheeting angle.   The MACLEW incorporates a sliding car on the clew plate of the jib.  The jib sheet is attached to this sliding car.  The result is that the sheet always forms a right angle with the after edge of the clew plate.

The jib boom option comes again with a few options, the most common version as shown in the diagrams, uses a straight boom which swivels on the deck. Sometimes this has a sliding car on the boom itself, similar to the boom end on a loose footed mainsail.

Another version is the Garry Hoyt jib Boom, pictured on the Island Packet 48, and also the Harbour 20.  For these pictures we thank Island Packet Yachts and Harbour Yachts (www.ipy.com.au) (www.harbouryachts.com.au).  This device is patented and is not easily retrofitted. As can be seen, the forward end extends through the deck where it is firmly bolted into the structure of the yacht. The Garry Hoyt Jib Boom precludes the need to hold the clew of the sail or the end of the jib boom down to the deck because the boom itself is very strong and effectively provides a boom vang function.

Both these jib boom approaches remove any need for whisker poles or jib poles when goose winged on a square run and improve downwind performance.

It is fairly obvious that they also increase the efficiency of the jib when not close hauled.  They do this by keeping the clew low and minimizing the extreme twist which bedevils most jibs, especially genoas when reaching.

All jib booms facilitate roller reefing jibs, but the Garry Hoyt version does it very well, note the picture of the Island Packet 48 with a full roller furling stay sail on a Garry Hoyt jib boom; the jib boom sets the staysail nicely.

Whilst retrofitting of a self tacking system takes some consultation and planning, it can make your boat much easier to handle. We do advise you to seek professional help with the design.   The other option is to buy a boat which already has this feature already sorted.  As a guide, we costed up most of the components we thought that a do-it-yourselfer would need to purchase to convert an existing say 40’ yacht to self tacking.   We included a recut of the jib to provide a clew plate, some track and a car plus a few reasonable quality turning blocks and cleats, etc, and arrived at about $2.000, which isn’t much when you consider the freedom it offers.

Self-tackers, new or retrofitted, offer tremendous benefits. If you want to fit a self-tacker to your boat, the important thing to keep in mind is simplicity.  The simplier the system is, the more reliable they tend to be.

NOTE:

Download the pdf of Self-tacking headsails to view the diagrams mentioned in the article above.