Yacht Sailing

Drifting Characteristics

To learn about the sailing yacht, go to an area of clear water and recognize how it behaves when drifting. When clear of other boats, put the engine into neutral, turn the yacht into the wind, and come to a stop. Release the tiller and make note on how the behaviour of the yacht.

The bow blows off downwind with the boat pivoting around its keel until taking up a natural drifting position. How quickly the bow blows downwind should be taken into account in situations when manoeuvring at slow speeds.

Some yachts lie naturally beam-on to the wind, but the majority point further downwind. In strong winds, steering the boat downwind with the windage of the rig is possible. Experiment with the angle either side of dead downwind that can be sailed under bare poles, and the speed the yacht moves through the water.

On the next phase, check how quickly the boat stops when put head-to-wind. Motor head-to-wind and put the engine in neutral. The yacht slows down and eventually stops. Note how far the boat travelled before losing rudder control and where the yacht came to a standstill. Repeat this sailing lesson with different starting speeds and in different wind and sea conditions building up knowledge of the yacht's behaviour.

Sailing Under Mainsail Alone

Hoist the mainsail alone and try sailing on all points of sailing. The results will depend on the rig configuration and the underwater hull shape. Modern cruisers sail well under mainsail alone, especially those with a fractional sloop rig - having a proportionally larger mainsail and relying less on the headsail.

The yacht sails downwind easily with only the mainsail, but its performance on a reach or when close-hauled is less impressive. Without a headsail the boat sails slowly on a reach, along with considerable weather helm with the boat trying to turn up into the wind.

Sailing close-hauled is more difficult. Try a tack and see if the yacht will turn through the wind and bear away onto the new tack. If the boat tacks and sails slowly to windward, then this knowledge gained is helpful when sailing slowly in confined spaces.

Next try to turn the yacht in a tight circle. It easily luffs-up, especially when pulling in the mainsheet rapidly at the start of the turn, but bearing away is more difficult without the headsail assisting the manoeuvre. The boat needs to be moving fast with the mainsheet let right out before the turn, or else the boat responds very slowly.

Having the confidence to sail the yacht slowly, in full control under mainsail alone, is a valuable skill. This allows the jib to be lowered before picking up a mooring, laying an anchor, or coming alongside. It can be particularly useful when dealing with rough weather, using a deep-reefed mainsail alone to sail comfortably in heavy conditions.

Sailing Under Headsail Alone

When sailing the yacht under headsail alone, set the largest headsail for the prevailing conditions and sail each point of sailing. The boat sails well downwind and is comfortable from there to a beam reach. It sails more slowly on a reach than with full rig, probably demonstrating lee helm.

If possible try sailing on a close reach and then close-hauled, but be aware yacht does not respond well to sailing close-hauled under headsail alone. The result depends on wind strength and the size of the headsail. Experiment changing headsails and note the difference. The results in ideal cruising conditions may not be the same in light or strong winds, or in rough seas. Finding this out in an exercise is more preferable than in a situation where the yacht's safety is at risk.

If the yacht is turned in tight circles under headsail alone, it bears away readily, but luffing will be difficult with the headsail attempting to counteract the force of the rudder. Move as fast as possible before luffing then pull in the headsail sheet slowly and let it shake at the luff, reducing its counter-effect on the rudder.

Probably the yacht will not tack enabling a turn full circle, but note how close to the wind the boat sails, while luffing and still under control. Beware of the speed of the boat, because slowing down too much causes the bow to blow off quickly downwind, and there may be difficulty in regaining control.

Sail Balance

When a sailing yacht gets out of balance, it is apparent with the boat heeling then slowing down developing more weather or lee helm. It is a relatively slow response and may be hard to spot when the yacht is not well balanced. Knowing the best sail trim for all conditions can overcome this.

Weather and Lee Helm

Sailing yachts have a degree of weather helm, but should never require large amounts of rudder deflection keeping the boat on course. Excessive lee helm should be reduced, as it makes it difficult keeping the boat on course along with being dangerous. A boat with lee helm and the steering is released for any reason, causes the boat to bear away, accelerating and sailing out of control.

Sailing on a close-hauled course in a good Force 3-4 breeze, there should be a small amount of weather helm. If there is excessive weather helm or worse still, lee helm, tune the sails to get the desired balance.

Turning Forces

The sails on a yacht create the same turning forces as on a dinghy but many skippers fail to use these forces, instead relying solely on the rudder to turn the yacht. This leads to loss of control in strong winds, so use the sails to assist when altering course.

This is especially important when bearing away in strong winds. Good mainsheet control by letting it out when bearing away stops excessive heeling.

Heaving To

Heaving to is a useful technique to stop the yacht;

• In order to prepare and eat a meal or
• To take in a reef when wind strength increases
• As well as a tactic for riding out rough weather.

The procedure for heaving-to requires the headsail to be sheeted to windward balancing the actions of the mainsail and rudder. The effectiveness of this manoeuvre depends on the type of yacht.

Long-keeled craft often heave to well, usually lying with the wind between 45° and 60° off the bow. Sailing yachts, with shallower hulls and shorter keels, do not heave-to so steadily, but achieve an angle of about 60° off the wind.

Experiment by trying different combinations of mainsail and rudder position. A common arrangement is where the jib is sheeted hard aback, the mainsail eased slightly, and the tiller lashed to leeward.

If the yacht does not lie close to the wind, use a smaller headsail. When a boat is hove-to, it drifts at between 90° and 135° to the wind direction, but lies more quietly than sailing.

Heave-to by backing the headsail to windward and this is done by tacking while leaving the headsail sheet cleated on the old side. The tiller is lashed to leeward, or wheel to windward, so that any sailing movement turns the boat towards the wind and then stops.

Hull Speed

Displacement yachts possess a theoretical maximum hull speed, which relates to the immersed waterline length. Designers integrate hull features into their yachts increasing waterline length when the boat is heeled; this in turns increases the length of the wave created by the hull when displacing the water.

Since the speed of a wave is governed by its length, the crest-to crest distance, the length of the wave created by the hull dictates the speed of the sailing yacht. The formula for wave speed is 1.34 times the square root of the wavelength in feet. Therefore, the hull speed of a 30-foot sailing yacht with a static waterline of 25 feet will be 1.34 times the square root of 25 = 1.34 X 5 = 6.7 knots.

When heeled to about 20 degrees, the yacht’s increased waterline length might give 7 knots as a maximum, and should be accepted that no matter how much sail that is put up, the yacht rarely exceeds 7 knots.

An inclinometer shows when the boat reaches 20 degrees of heel; not only does this degree of heal give a comfortable working angle below, it indicates the correct amount of sail for the given wind speed. When in light airs the boat heels less, but in these conditions, an upright yacht is ideal, reducing the wetted surface to reduce hydrodynamic drag on the hull.

Speed Polar Diagram

Maintaining maximum boat speed on all points of sailing will require consulting or constructing a speed polar diagram for the principal points of sail. This is where the speed of the yacht is estimated for the points of sail, close-hauled, fetch , close reach, beam reach, broad reach and run against a given number of wind strengths.

Sail combinations for each wind speed are noted on the left side of the diagram and are a reminder of which sails are required andtheir reefing positions.

The time taken to complete the construction of a speed polar diagram for a boat is profitable exercise, which helps improve the sailing speed of the yacht.

Wind and Tide Factors

An additional factor that affects the speed of sailing yachts is that produced by the wind or the tide, or the combination. Coastal waters have waves that are usually short and steep and, applying the formula used to find hull speed, a wave with a length of 4 feet will move at 2.68 knots. If sailing a 25-foot yacht close-hauled it will be sailing against at least five of these oncoming waves at any one time.

Overcoming the resistance of short, steep waves, requires changing course to a close reach to increase the sail power and at the same time decreasing the impact of the waves by meeting fewer crests because the boat is sailing at a greater angle.