An understanding of how to trim your sails well is very useful from a cruising point of view in terms of maintaining boat speed, contributing to the balance of your yacht, and reducing unnecessary wear and tear.
Most yachts are powered up to windward in around 14 knots true wind, that is heeling as much as they should without excessive helm. However yachts doing extended cruising tend to be loaded with water, fuel and provisions and so may carry full sail area in slightly more wind. For trade wind sailing which is generally done reaching, full sail can be carried in considerably more wind.
There is a misconception, I believe from old classic yachting photographs, that having sails well twisted (that is leach very open) is to be recommended, but in fact this is quite inefficient as much of the power of the sails is being lost. A best indication of headsail trim is to have tell-tales spaced in several positions along the luff and the sail is at its most efficient when all of the tell-tales lift or break at the same time. If the leech is too closed (the leeward tell-tales stalling up high before down low then your sheeting angle is too far forward and your genoa cars should be moved aft. Once the yacht begins to become overpowered the genoa cars should be moved aft to open the leech which de-powers the sail.
With the mainsail it is the tell-tales on the leech that we are using to see what’s going on and the sail is perfectly set when all tell-tales are flowing aft. The most critical ones are on the upper leech because it is the upper leech which contributes most to the heeling of the yacht once it becomes overpowered. Once you are overpowered there may be three controls available to you to de-power the sail. Firstly, ease the vang slightly as this allows the boom to rise and open the leech, secondly and probably more obviously ease the mainsheet slightly.
However, if your yacht is fitted with an adjustable back-stay then the first thing to do is to take on some backstay which bends back the top of the mast opening the leech and at the same time pushes the middle of the mast forward flattening the sail as well. It may seem blatantly obvious, but I know I’ve made the same mistake, but if in doubt then take a reef in and/or partly furl the headsail before you become overpowered. In a building trade-wind it is not unusual to become overpowered before you realise it, so remember that being overpowered is usually slower and is putting considerably more load (therefore wear and tear) on the sails, steering system, standing and running rigging.
If running before the wind with a spinnaker or cruising chute and you begin to feel overpowered turn away from the wind to shadow the sail behind the mainsail and then bring it down. The latest thinking is using what are called furling Code 0 sails which look like a cross between a genoa and asymmetric spinnaker with a fine entry and can be progressively furled as required. They use a single line furler which is very easy to furl, even under load and therefore the sail can easily be handled while sailing single-handed if your partner or crew are off watch.
Anything you can do to reduce chafe of sails is well worthwhile, so ends of speaders should have leathers, lifelines forward should have rigging tape to stop the split-rings from catching the headsail, and if you have overlapping headsails chafe protectors on the shrouds will pay dividends.
By Lee Condell.
Lee Condell is a Director of Performance Boating Sales the agents in Sydney for new Jeanneau yachts. He cruised his own 44 foot yacht from Sydney to the West Coast of Ireland covering 26,000 miles and 27 Countries in a 12 month cruise.