Performance Boating – basics of sail trim:

Many people often comment to us how we seem to be very focused on the performance and handling of our yachts here in NSW, and they are correct for a number of reasons. Firstly, we largely sail in enclosed waters where conditions are very gusty, so having your yacht round up can at least be embarrassing and at worst cause an accident on a busy weekend. Secondly, because we regularly sail with other yachts in close proximity it’s very noticeable how your boat is performing relative to others.

There are some key elements as to how a yacht will perform, but primarily to get the best out of your yacht the bottom should be free from growth, the sails in good shape (not too stretched or full), the rig tuned properly and the sails well-trimmed. Sail trimming is what we will discuss in this note.

Let’s keep things straight-forward and base this on simply white-sailing, that is just with mainsail and headsail. There is a point of wind strength at which a yacht is just perfectly powered, usually about 12 knots of true wind strength. Up to that point we are looking for power and wanting to trim our sails accordingly, once we start to get over-powered we then want to start losing power out of our sails.

Under that wind-strength we’re looking to have the headsail trimmed correctly, that is the halyard tension so that there is little or very little slack, and the car position so that the tell-tales break evenly up the luff of the sail. If you don’t have tell-tales on your headsail you can buy stick-on ones cheaply at any chandlery.

On the mainsail if you have a traveller you are looking to keep the boom up to the centre-line upwind, then sheeting on so that all leech tell-tales are streaming, particularly the upper one. The outhaul should be released to allow some fullness in the mainsail.

If you are sailing off the wind the headsail car position should ideally be moved forward to keep the luff even and not twist the leech open too much. Similarly the vang and mainsheet traveller should be used to keep the leech tell-tales flowing evenly and keep the power in the upper leech in particular.

Once you start getting overpower the first step is to depower the mainsail by taking on the outhaul. If you have an adjustable back-stay then this should be taken on next, then lower the mainsheet traveller a little. If you are still being overpowered then ease some main-sheet. If the increased wind is consistent then also move the headsail car back to twist and de-power that also.

On yachts with large overlap headsails if the wind continues to increase then start by furling the headsail. For yachts with short-overlap headsails it is best to reef the mainsail first.

Being overpowered is not fast! And especially when passage sailing it is best to be conservative, as being overpowered not only puts undue strain on everything, but is often no quicker and almost always more uncomfortable!

Remember, if you’ve been sailing in a lot of wind and have therefore needed to tighten your headsail halyard to keep luff tension, it’s important to let this off to your normal halyard tension before you furl your headsail, as this will put undue stress on the sail material and reduce the life of the sail.

Trimming sails well is a rewarding part of our sailing skills that will make your sailing more enjoyable, so well worth picking up a book, or finding videos and information on sail-trim online.