Having sailed for over 40 years we sometimes forget that many have not been as lucky to have been introduced to sailing at a young age, so from time to time we need to remind ourselves that there are those who may not have had the opportunity to learn what we have from years of cruising and racing, so here we explain some of the basics of sail trim for yacht cruising.
Genoa: The headsail car controls how the headsail presents to the wind. If the car is too far forward the leach of the sail closes too much and this causes the yacht to over-heel and also backwind onto the mainsail. If the car is too far back then the leach is too open losing power and luffing unnecessarily. Every owner should establish a ‘datum’ car position for their full headsail (fully unfurled & assuming sufficient halyard tension) which should ideally be done in about 10 to 12 knots of steady wind. Before carrying out this exercise it is helpful to have tell-tales at quarter, half and three-quarter luff height, though you can do it by sighting the luff carefully. A set of tell-tales can be bought for about $10 at your local chandlery.
So, in the required conditions with sufficient halyard tension watch the luff of the headsail as you sail upwind and when you start to sail slightly above close-hauled and the headsail starts to luff check if the tell-tales break (or back-wind) evenly up the sail. If the upper tell-tales on the leeward side flutter from horizontal first then the car position is too far back, and vice versa. Once the datum has been established mark the position with a permanent marker or such-like. For ever more you now have a standard car position.
Only Sail to windward with your tell-tales flowing parallel until the boat is getting fully powered up, beyond this wind speed sail so that your tell-tales are luffing on the windward side.
Unless you really want to go for performance this standard car position will work fine from zero to fully powered which on most yachts is between 12 to 14 knots of true wind. When the yacht is beyond fully powered, and by this we mean that the yacht is heeling excessively and the helm heavy (weather helm), then we need to start looking at de-powering the sail-plan. The first step is to move the car position aft a few inches to open the upper leach, reduce heel and stop any back-winding into the mainsail. Typically this will carry you through another few knots of wind before it is time to take in the first furl on the headsail. The golden rule is that any excessive weather helm or heeling is slow, inefficient and uncomfortable, so as soon as there is any sign of the above it’s time to start reducing sail. Although it does vary from yacht to yacht it usually makes sense to furl some headsail first before considering a reef in the mainsail. However, note that as you furl the headsail the car position should be moved correspondingly forward, otherwise the upper leach of the headsail will open and flap excessively.
Mainsail: Whether your mainsail is conventional or in-mast furling the same principals apply, so the depth of the sail and how tight the leach is are the critical things in a general sense. The biggest contributor to weather helm is a mainsail that is too full, either because the sail itself has become to full, or not enough outhaul is being used. And the biggest factor in a yacht heeling excessively is the mainsail leach being too tight or closed, or simply having too much sail up. So in the fully powered up mode as described above the mainsail outhaul should be on close to maximum, the boom on or close to the centreline, and the top leach tell-tale flowing freely. As the wind increases the upper leach of the main should be ‘opened’ by easing some sheet and easing the boom vang. This allows the boom to rise and the top of the mainsail to twist open. If this has been done and the genoa car moved aft and you are still over heeling then the next step is to furl some headsail, followed by your first reef. It is often surprising how much better a yacht feels once a reef has been taken in as so often we tend to hang onto full main well after we should have reduced sail. All of a sudden the boat is more balanced, upright, comfortable and faster and generally feels a whole lot better.
So try these simple tips to further your enjoyment of sailing and remember that we’re only a phone-call away if you have any questions.
Performance Boating directors Ron Jacobs and Lee Condell have a wealth of experience with Ron having raced yachts Internationally at the highest level while Lee has raced extensively and also cruised his own yacht from Australia to Europe.