Sail Trim and Boat Handling Techniques - Optimise Performance

Prerequisites

This lesson builds on RYA Competent Crew skills. Before starting you should:

• Know the parts of a yacht, its sails and running rigging (halyards, sheets, kicker/vang, traveller, outhaul, cunningham, reefing lines).
• Be able to helm on all points of sailing, and tack and gybe as crew.
• Be able to handle lines, cleat and winch safely, and throw a line.
• Understand the points of sailing and apparent wind.
• Have the recommended pre-course experience for the Day Skipper practical: about 5 days and 100 miles aboard.

At Day Skipper level the step up is responsibility: you are no longer just trimming a sheet when asked, you are deciding the sail plan, when to reef and how to bring the boat alongside, and you are briefing and directing the crew.

Learning Objectives

By the end of this lesson you will be able to:

• Explain how a sail produces drive, and use telltales to trim headsail and mainsail.
• Use the mainsail controls (sheet, traveller, kicker, outhaul, cunningham) and headsail sheet leads to shape the sails for different wind strengths.
• Choose a sail plan for the forecast before leaving harbour, and change or drop a headsail at sea (RYA syllabus: managing the sail plan, headsail changes).
• Explain helm balance and correct excessive weather helm.
• Decide when to reef and carry out slab reefing and headsail furling.
• Heave-to.
• Explain throttle and gear control, the rudder and prop wash, pivot points, prop walk, steerage way and windage, and use them under power (RYA syllabus: handling under power, the basics).
• Go astern under control, read the signs of wind and stream, and judge drift and speed over the ground with transits (RYA syllabus: going astern, effect of wind and stream, judging speed and drift).
• Turn a yacht in a confined space using prop walk and the wind (RYA syllabus: tight turning).
• Plan and brief a berthing approach and departure for different wind and stream directions, including ferry gliding, berthing in a stream, mooring to a wall, rafting up and leaving a raft (RYA syllabus: coming alongside, berthing, leaving a berth).
• Moor bow-to or stern-to a quay with an anchor or lazylines (RYA syllabus: stern and bow-to mooring).
• Pick up and leave a mooring buoy under power and under sail, and anchor under sail (RYA syllabus: mooring under sail).
• Tack and gybe under skipper control, brief the crew, and manage the boat on all points of sail.

These map to the Day Skipper Practical syllabus topics "Handling under sail" (trim, tacking and gybing, reefing and heaving-to, sail changes), "Handling under power" (the basics, going astern, wind and stream, judging speed and drift, tight turning, coming alongside), "Berthing and leaving a berth", "Stern and bow-to mooring" and "Mooring under sail". The assessor expects you to explain what you are doing and why, brief the crew, and do it safely and calmly with a boat that is under control throughout.

How Sails Work

Lift, not push

On every point of sailing except a dead run, a sail works like an aircraft wing. Air flowing round the curved leeward side travels faster and its pressure drops; air on the windward side slows and its pressure rises. The pressure difference produces a force roughly at right angles to the sail. The keel resists the sideways part, so the boat moves forward, with some heel and a little leeway. The diagram shows the principle.

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The trimmer's job is to set the sail at the right angle to the apparent wind (angle of attack) with the right amount of curve (depth or draft) and twist. Too little angle and the luff flaps; too much and the flow breaks away from the leeward side (stall), producing heel and drag instead of drive.

Basic trim rule

For any sail on any point of sail: ease the sheet until the luff just starts to lift (flutter), then trim in until it just stops. That is the most efficient angle. When the course or wind changes, repeat.

Using Telltales

Telltales are short strips of wool or ribbon on both sides of the sail, near the luff of the headsail and on the leech of the mainsail. They show you the airflow you cannot see. The RYA notes put it simply: when close-hauled, sail so that the telltales on both sides of the headsail fly nearly horizontal. Too close to the wind, the windward ones lift: steer away. Too far from the wind, the leeward ones droop: steer up.

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The photograph below shows a single telltale streaming aft from the leech of a mainsail. A ribbon like this, flowing smoothly behind the sail, indicates attached flow. A telltale that wraps or hides behind the sail indicates a stalled, over-sheeted leech.

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Image: Butterfly voyages - Serge Ouachee.jpg), CC BY-SA 3.0, via Wikimedia Commons.jpg)

When both windward and leeward telltales stream aft, the flow is attached on both sides and trim is correct. When they misbehave:

A memory aid for the helm upwind: steer towards the telltale that is misbehaving. Windward telltale lifting: steer away from the wind (bear away). Leeward telltale fluttering: steer towards the wind (head up).

Headsail luff telltales and sheet lead position

Most headsails have three sets of telltales spaced up the luff. If they all break at the same time as you slowly head up, the sheet lead is correct. If they do not:

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• Top telltales break first: the top of the sail is too open (too much twist). Move the sheet car forward to tighten the leech.
• Bottom telltales break first: the foot is too full or the top too closed. Move the car aft.

Moving the car forward increases leech tension and puts more depth in the foot: more power, good for light and moderate winds. Moving the car aft flattens the foot and lets the top of the sail twist open, spilling wind: less power, good in strong winds. On a furling genoa, move the car forward each time you roll some sail away, because the clew rises and moves forward as the sail gets smaller. When you change to a different hanked-on headsail you must also move the car, because the clew of each sail is in a different place.

Mainsail leech telltales

On the main, watch the telltale at the top batten. It should stream aft most of the time, occasionally curling behind the leech. If it is permanently hidden behind the sail, the leech is too tight (over-sheeted or too much kicker): ease. If it streams constantly and the top of the sail is flapping, the leech is too open: tighten sheet or kicker. Close-hauled, the mainsheet adjusts the leech telltales; on a reach or run, when the sheet is eased, the kicking strap does the job.

Mainsail Controls

As a guide, the deepest part of the mainsail should be about 45 to 50 per cent aft from the luff, and of the genoa about 35 to 40 per cent. As wind increases, draft moves aft by itself; pull it forward again with cunningham or halyard tension.

The traveller is the most useful control upwind in gusty conditions. The diagram shows its effect.

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In a gust, drop the traveller to leeward. The main keeps its shape but meets the wind at a smaller angle, so heel and weather helm reduce while the boat keeps driving. When the gust passes, bring it back up.

The Slot and Sail Interaction

On a sloop the headsail and mainsail work as a pair. Air flowing through the gap between them (the slot) is accelerated and steered along the leeward side of the main, helping both sails.

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If the genoa is sheeted too hard or led too far inboard, the slot closes and the main's luff backwinds (bubbles). Ease the genoa slightly or move its lead outboard. Some backwinding of the main luff is normal close-hauled in a breeze, but a large bubble means the slot is too tight or the main too full.

Points of Sail

• Close-hauled (about 40 to 45 degrees to the true wind): sails trimmed in, traveller near centre in light airs. Steer by the headsail telltales. Pinching (too high) slows you; footing (a few degrees lower) is faster but makes less ground to windward. Find the best speed made good towards the wind.
• Close reach and beam reach: ease both sheets until the luffs just lift, then trim back. Ease the kicker a little, ease the outhaul for power. The beam reach is usually the fastest and most comfortable point of sail.
• Broad reach: ease sheets well out. The kicker now controls leech twist; firm it to stop the boom lifting.
• Running (wind dead astern): risk of an accidental gybe. Steer 10 to 15 degrees off a dead run, rig a preventer from the boom end to a bow cleat and back to the cockpit, and consider goose-winging the headsail (poled out if possible). Keep crew heads clear of the boom's path.

Managing the Sail Plan

Sail selection is a key part of preparing for sea, and the RYA practical notes are blunt about it: if in doubt, put in a reef and prepare a smaller headsail before you depart; it is always easier to put more sail up than to take it down. A boat can carry more sail downwind than upwind, so think about the sail plan before you turn to windward, not after. A light modern boat is more sensitive on the helm than an older, heavier one, and needs reefing earlier.

Boats are designed to sail upright or heeled to no more than about 20 degrees, and that is where they are fastest and most comfortable. The signs of excessive heel are easy to see: moving around the boat becomes difficult, steering and manoeuvrability reduce, vision from the helm reduces, and boat speed drops. If the boat feels uncomfortable, reduce sail. Reef early and be ready to ease the mainsail in gusts.

The RYA guideline table for a typical modern cruising boat, reducing headsail first and then mainsail to keep the plan balanced:

Three reefs reduce the mainsail area by about 60 per cent. In very strong winds a trysail, a small, strong, loose-footed sail set in place of the main with its own sheets, is used instead. Every boat differs: learn the thresholds for yours.

Headsail changes

Roller furling. To unfurl, ease the furling line under tension while pulling in the headsail sheet, so the sail cannot unroll with a bang. To furl, ease the sheet while hauling in on the furling line, keeping a little tension on the sheet so the sail rolls tightly and smoothly. A deeply furled genoa loses shape and becomes baggy; move the sheet car forward and do not expect good windward performance from a sail rolled to half its size.

Hanked-on headsails. A traditional wardrobe runs from the No. 1 genoa (light winds), through the No. 2 genoa and the working jib (No. 3), down to the storm jib. You can prepare the new sail for hoisting, hanked on below the old one, before you drop the old one, which keeps the foredeck time short. Each change of headsail needs the sheet car moved to suit the new clew position.

Dropping a headsail (the RYA sequence): ease the halyard; pull down on the luff, keeping some tension on the sheet so that neither the sail nor the sheet goes over the side (a large headsail needs two people on the foredeck); unclip the halyard from the sail, clip it to the pulpit and re-tension it so it cannot swing; pull the sail back along the deck and roll it so it can be tied to the guardrail if it will be needed again, or fold it from the clew forward, remove the hanks and bag it; keep the bag tied in place; then coil and tidy the sheets and halyard.

Heave-to for sail changes. Heaving-to is a good way to drop a headsail or put in a reef: the motion eases, the boat steadies and the crew finish the job faster. Anyone leaving the cockpit for a sail change wears a harness and clips on, works on the windward side, and the companionway hatch is closed so that nobody falls down it.

Tacking and Gybing as Skipper

Tacking

A good tack keeps speed on and the crew coordinated.

1. Brief and prepare. Check the new side is clear of traffic and obstructions. Say what you will do: "Ready about". The headsail trimmer puts the lazy sheet on its winch, flaked clear, and takes the working sheet off the self-tailer but holds it with a turn.
2. Build speed. Bear away slightly to gain speed for the tack. A yacht doing 5 knots tacks through about 80 to 100 degrees; one at 2 knots may stall in the eye of the wind.
3. Call "Lee-oh". Steer smoothly and not too fast through the wind, about 3 to 4 seconds from head-to-wind to the new close-hauled course. Ease the main slightly as the boat turns (helm sheet in the traveller or crew).
4. Release and trim. As the headsail luffs and is about to blow across, release the old sheet. Winch in the new sheet quickly but do not oversheet; stop hauling when the sail is nearly full.
5. Settle. Once speed has returned, trim both sails to the telltales and take stock.

Common faults: tacking too slowly and stopping head to wind ("in irons"), releasing the sheet too early or late, and over-sheeting the headsail so the boat stalls. If in irons, back the headsail to the opposite side (pushing the bow round) and steer to the new side, or use the engine.

Gybing

A gybe moves the stern through the wind, so the boom crosses with the sail full. In winds above 15 knots or in waves the boom can cause injury or break the rig.

1. Brief the crew: warn everyone of the boom and the sheet.
2. Steer to a dead run (the wind directly astern) as the sail is hauled in by hand until the boom is near the centreline.
3. Call "Gybe-oh" and steer through the wind. As the boom crosses, the crew lets the sheet out quickly.
4. Bear up to the new course and trim, then release any preventer.

If the wind is strong or the sea rough, consider a "chicken gybe" (a tack): turn the other way, upwind through the wind and back downwind. It takes more sea room, but gives complete control of the boom. Never gybe with a preventer rigged.

Helm Balance

Weather helm and lee helm

Helm balance is the boat's tendency to turn on its own. It depends on where the centre of effort (CE) of the sails sits relative to the centre of lateral resistance (CLR) of the hull and keel. When the CE is aft of the CLR, the boat wants to turn into the wind: weather helm. When it is forward, it wants to turn away: lee helm. Heel also increases weather helm because the drive moves out to leeward of the hull.

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• Slight weather helm (3 to 5 degrees of rudder) is good. It gives feel, and if the helm is let go the boat rounds up and slows rather than bearing away and gybing.
• Heavy weather helm is bad. The rudder acts as a brake, the helm is tiring, and in a gust the boat can round up out of control (broach). The RYA lists the symptoms of too much sail on a windy day as weather helm, excessive heel, a slower yacht and broaching in gusts.
• Lee helm is dangerous. If the helm is released, the boat bears away and may gybe. It usually means too much headsail and too little main in light winds; it is rarely a problem on a modern yacht.

Curing excessive weather helm

In order of ease:

1. Ease the mainsheet or drop the traveller in gusts.
2. Flatten the main: tighten outhaul, cunningham and backstay (if adjustable).
3. Reduce heel: heel is the main cause of weather helm. Aim for no more than about 20 degrees.
4. Reef the main. Reducing mainsail area moves the CE forward and reduces weather helm.
5. Avoid reducing headsail alone in a blow: it moves the CE aft and makes weather helm worse. Reef both in step.

Reefing

When to reef

The RYA rule is simple: reef early. If you are wondering whether to reef, you should already have done it. Reefing is easy in 15 knots and hard, wet and dangerous in 30. Signs it is time:

• Heel regularly over 20 to 25 degrees.
• Heavy weather helm, rounding up in gusts.
• Crew uncomfortable or anxious.
• A forecast increase, or approaching squall clouds.
• Before dark, before a tidal race or before entering harbour.

Typical thresholds for a 30 to 40 ft cruising yacht are shown below, but every boat differs. Learn yours.

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Remember apparent wind falls when you turn downwind. Reef before you turn back upwind, and consider reefing before bearing away onto a run in a building breeze, because rounding up to reef later will be violent.

Slab (jiffy) reefing procedure

Brief the crew first, check the lazy reef lines are clear, and make sure everyone knows who does what. To make reefing easier, reduce heeling by easing the sails or heaving-to; crew going on deck clip on and use the windward side.

1. Head the boat close to, but not straight into, the wind: a close-hauled or close reach course, or heave-to, so the main can be depowered. Do not reef on a run with the boom pressed against the shrouds.
2. Ease the mainsheet and kicker to spill wind from the main.
3. Raise the topping lift to take the weight of the boom and de-power the sail, so the boom does not drop into the cockpit.
4. Lower the main halyard to the pre-marked reef position.
5. Secure the new tack: pull the sail down and hook the luff cringle over the ram's horn at the gooseneck, or pull in the tack reef line.
6. Winch the halyard tight until the luff is firm.
7. Winch in the clew reefing pennant until the new foot is tight along the boom. The sail must be flapping, not full, while this is done; watch for jams.
8. Ease the topping lift, pull in the mainsheet and kicker, and resume course.
9. Tidy the other reefing pennants and lines, and put a sail tie through the clew cringle and around the boom to reinforce the reef in case the pennant fails. Tidy the loose sail onto the boom with sail ties passed between the sail and the boom, tied with reef knots or bows. The clew and tack take the load; the ties only hold the bundle.

Now the sails are balanced in size again, the boat sails straight, fast and comfortably. A practised crew can do this in two to three minutes. With single-line reefing everything is led to the cockpit, but the sequence is the same. There are several other reefing systems depending on how the boat is rigged; slab reefing is the commonest.

Headsail furling and in-mast mainsails

Roller-furling headsails are reduced by easing the sheet slightly while hauling in the furling line, keeping some tension on the sheet so the sail rolls tightly. In-mast furling mains: ease the outhaul while tensioning the furling line, keep the boom at the correct angle (usually slightly above 90 degrees to the mast) and never force a jammed sail; check for wrinkles or a twisted luff.

Heaving-To

Heaving-to stops the boat in a stable, comfortable position for reefing, eating, sorting out a problem, waiting for a tidal gate, or as part of a man overboard recovery. To heave to from close-hauled:

1. Tack without releasing the headsail sheet, so the headsail is backed (held to windward).
2. Ease the mainsheet partly.
3. Put the helm to leeward and secure it: tiller lashed to leeward, or wheel turned to windward and locked.

The backed headsail pushes the bow away, the main and rudder push it back towards the wind, and the boat lies about 50 degrees off the wind, fore-reaching slowly at 1 to 2 knots and drifting to leeward. Check you have plenty of sea room to leeward.

Boat Handling Under Power: The Basics

Throttle and gear

One lever usually controls both gear and throttle. Pushing it forward or back by one click engages gear with the engine idling; further movement increases power. When changing between ahead and astern, rest the lever in neutral for a moment to reduce the chance of crashing the gearbox.

The rudder and prop wash

A boat only reacts to steering when water is flowing over the rudder. That flow comes from three sources: the propeller (prop wash), the boat moving through the water, or a stream running past the rudder. Yacht rudders are large and will steer at very slow speeds, but not when the boat is stopped and the propeller is idle. Turning the rudder and then engaging ahead throws prop wash over one side of the rudder, which makes it far more effective and turns the boat in a smaller circle. Going astern, the prop wash does not pass over the rudder, so steering depends entirely on the water flow gained by moving astern. The rule in tight spaces is therefore: turn the rudder first, then apply power.

Pivot points

When a boat turns, the bow goes one way and the stern the other, and because the rudder is at the stern it is really the stern that is being steered. Motoring ahead, a yacht pivots about a point roughly a third of the way aft from the bow, about at the mast: watch the stern, which swings wide, and beware of hitting obstructions with it. Going astern, the pivot point moves to about a third from the stern, and now the bow swings the most, travelling about twice as far as the stern. Look both forward and aft when reversing.

Propellers and prop walk

Propellers are handed, left or right, according to their direction of rotation in forward gear. Besides pushing the boat along, the propeller's rotation also walks the stern sideways; this prop walk (transverse thrust) is most noticeable going astern from rest. Most yachts have a right-handed propeller, which in reverse kicks the stern to port. The diagram shows the effect.

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To find the direction on your boat, run the engine astern while securely moored and watch the wash: it is more visible on one side than the other, and the stern tries to move. Or in open water, stopped, engage astern and watch which way the stern goes. Prop walk can be used to advantage in tight turns and must be allowed for in every reversing manoeuvre: a right-hand-prop yacht berths most easily port side to, because the burst astern that stops her also swings the stern into the pontoon.

Steerage way and windage

Below about 1.5 to 2 knots steering is poor. A boat that has stopped, or is moving slowly, drifts downwind, and the bow always drifts first because it has less grip in the water and more windage than the stern. Good wind awareness is essential: read flags, wind indicators on the mast and the ripples on the water before every manoeuvre. The easiest way to hold position in a breeze with no stream is to reverse gently and sit stern to wind; reversing moves the pivot point aft and lets the bow blow downwind of the stern where it is stable.

Going astern

The RYA notes list three effects of going astern:

1. The pivot point moves aft, so the stern seeks the wind as the windage of the bow takes charge.
2. Prop walk may kick the stern one way as the propeller bites.
3. Steerage way is only gained once the boat is actually moving astern.

Technique: start from stopped or slow in the water; if the boat does not like going astern, start off stern to wind. Use positive power to get moving, then ease off. Use minimal rudder. Keep both hands on the wheel or tiller, because the steering becomes heavy, and if the yacht sheers off excessively, go ahead to stop her and start again. Too much speed or too much rudder astern can slam the tiller or wheel over violently and break the steering gear. Most modern yachts handle well astern; some older boats are difficult.

Streams

A stream is caused by tide, river flow or local water movement such as around locks. Think of it as a conveyor belt. Travel with the stream and you pass the shore faster; against it, slower; across it, you are pushed sideways. When coming alongside, berth into the stream: the boat is slower over the ground, with more water flowing over the rudder for the same speed. Signs of the stream's direction:

• a moored boat disturbing the flow, with a wake downstream of it
• bubbles or debris flowing past a moored boat or pile
• tight mooring lines indicating pressure from one direction
• floating weed streaming downstream along a pontoon
• water piled up on the upstream side of piles and buoys.

If you are still unsure, motor slowly across the stream and watch the drift.

Judging drift and speed with transits

As a boat slows, drift from a cross stream or crosswind increases. Use transits to see it. Approaching a buoy or pontoon in a crosswind, pick an object beyond it and keep the two in line; if the far object opens to one side you are being set that way, so steer back towards the first reference until the transit is regained. To judge speed over the ground, find two objects abeam and watch them move past one another. In a strong stream the electronic log may show 2 or 3 knots when the boat is stationary over the ground; only a transit will tell you the truth.

Tight Turning

Many marina fairways are no wider than 1.5 to 2 boat lengths. For a tight turn, start from stopped or very slow: speed carried into a turn widens the turning circle and makes the yacht slide sideways.

1. Position the boat central to the gap. Put the rudder hard over and give a short burst of power ahead. The bow starts to turn.
2. Go astern to stop the yacht moving forward. The rudder can usually be left where it is, because steerage way astern is not gained, and prop walk helps or hinders according to its direction. Engage neutral.
3. A final burst ahead with the rudder still over keeps the boat turning. When she points the right way, straighten the helm.

Turning in wind. Turn the bow through the wind: once the bow is through the wind, the wind helps the turn, and the yacht stays away from downwind dangers. Keep the bow turning throughout. Turning in a stream running through a marina aisle: turn the bow through the stream. Using prop walk. With a right-hand propeller, turning to starboard is easier because the burst astern walks the stern to port, which helps the turn; with no wind or tide, always turn the way prop walk helps.

A typical 10 m yacht will turn in about 2 boat lengths with 3 or 4 shuffles. Practise in open water first. Small bursts of power with the rudder already over, and then stopping, are better than long runs.

Coming Alongside

Good communication between skipper and crew is essential. Make a plan, tell the crew what it is and what each of them will do, and if the manoeuvre seems complicated draw it on paper so that everyone understands their job.

• Lead the warps from the cleat, under the guardrail and back over the guardrail, so that they are ready to pass ashore without fouling.
• Fender the beam and the extremities of bow and stern, which may touch first. One person with a roving fender is useful.
• On the approach, ask the crew to sit down so they do not obstruct your vision, and ask the crew at the bow to call the distance.
• Pontoons are slippery. Step ashore when the boat is alongside; do not jump.
• The stern line is led aft to help slow the boat and the bow line taken forward. Take a turn around the cleat and surge the line rather than holding it by hand.
• Once alongside, stop the boat with the engine astern, remembering that if astern is used to stop, the stern will pivot away from the pontoon on a right-hand prop berthed starboard side to.
• Bow and stern springs prevent fore-and-aft movement. Take the slack out on board so that stray rope is not left on the pontoon, and secure with a bowline, a round turn and two half hitches, or by cleating off.

The effect of wind and tide on the approach

Combine wind and tide before you decide direction. Worked example: a 10 m yacht approaches a pontoon with 3 knots of tide from astern and a 10 knot wind on the beam. Down-tide, the boat's ground speed is its speed through the water plus the tide, so at 2 knots through the water it is moving at 5 knots over the ground. Stopping would need a lot of reverse power and risk a damaging approach. Instead, turn and approach into the tide: at 2 knots through the water, over the ground the boat is moving at only 1 knot, so it gives control with the rudder and time to put lines ashore. Always judge a berth by speed over the ground.

Berthing

Assessing the situation

The direction and strength of wind and stream change in different parts of a harbour or marina. Assess the conditions in the berth itself before committing to an approach: carry out a trial run past the berth, and have an escape route. Brief the crew and have fenders and warps in place before starting the approach. Wind close to a harbour wall often changes in strength and direction, so check flags and wind indicators near the proposed berth. Small white horses are a good indicator of wind-against-tide. The tidal stream in deep channels may be strong while further inshore it is slack or even reversed. Then decide your approach. The diagram summarises the main cases.

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Basic approaches

Approach at the slowest speed that still gives steerage way and control; usually only the boat's momentum and idle ahead are needed.

Berthing in a stream

The stream is the key factor. Approach with the stream and the speed towards the pontoon increases; approach into the stream and it decreases. Approaching into the stream gives the slowest approach and greatest control, because water flows over the rudder without the boat gaining speed over the ground. Judge your speed by points abeam. Aim forward of the berth at a shallow angle, because the stream will push the yacht sideways, and when in position angle the yacht slightly so that the stream moves her sideways onto the pontoon. Aim too close to a boat downstream and your stern may collide with it as the stream sets you down.

Ferry gliding is the way into a tight berth when a stream is running. Stem the stream, motoring into it so that the boat is neither moving forwards nor backwards over the ground; a transit abeam confirms it. Then steer slightly towards the pontoon while keeping the transit: the water flowing over the rudder gives steerage, the stream pushing on the angled bow moves the boat sideways, and she crabs into the berth under full control.

Downstream berthing is difficult and best avoided: as the boat slows she loses steerage way but is still being swept towards the pontoon, out of control. If a downstream berth must be approached, use the shallowest possible angle and get the stern line or an amidships line made fast quickly. Approach at too steep an angle and the stream will pin the bow and swing the stern out into the fairway.

Mooring to a wall

Check there is sufficient depth at low water. Warps must be adjustable from the boat, because you may not be able to get ashore when the boat has dropped below the quay. A warp from the amidships cleat to a ladder ashore is a useful temporary attachment while the proper warps are made fast. If a rise and fall of tide is expected, the warp length should be about three times the range of tide, so that the angle does not become too steep. Rig a fender board across two fenders, or tie the fenders horizontally with an extra line, so that they cannot be pushed aside by the piles. Check that masts and spreaders will not touch the wall or an adjacent boat when the boat heels or the tide drops.

Rafting up

Ask the other boats their departure times before you decide where to raft. Rig fenders higher than for a pontoon, because yachts' topsides vary. Once alongside, walk around the bow of the other boat, never through its cockpit. Secure with bow and stern breast lines to the inside boat, then fore and aft springs, and then lead your own lines ashore so that the load of your boat is not taken by the other.

Springs and lines

The diagram shows the lines used to secure alongside.

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• Bow and stern lines lead forward and aft at an angle, holding the ends in.
• Fore spring (head or bow spring) runs from the bow aft to the pontoon. It stops the boat moving forward.
• Aft spring (back or stern spring) runs from the stern forward to the pontoon. It stops the boat moving astern.
• Breast lines run square to the boat and hold it close; use them only for short stops, as they cannot allow for rise and fall in tidal waters.

The springs do most of the work. A midships cleat line led aft to the pontoon is the single most useful line when arriving short-handed: once on, a little forward gear holds the boat alongside while the crew add the rest.

A worked port-side-to berthing

The sequence below shows an approach exploiting prop walk with a right-hand propeller.

1. Brief the crew: "Port side to. Fenders out port side at the widest point. Jane on the bow line, Mike on the midships line, Tom on the stern line. Step off only when the boat is alongside and not more than a short step; never jump."
2. Approach slowly at about 20 to 30 degrees to the pontoon, into the stream if there is one.
3. About a boat length off, put the helm to bring the boat parallel and engage astern briefly. Prop walk swings the stern to port, towards the pontoon, while the boat stops.
4. Midships line or stern line ashore first, then bow line, then springs.
5. Starboard side to with the same prop: approach at a shallower angle and slower, because the burst astern will kick the stern away from the pontoon. Get a stern line or aft spring on early.

Leaving a Berth

Plan the manoeuvre considering the effects of stream and wind, and brief the crew so that everyone knows their role. Rig the mooring warps as slip lines, doubled back so that they can be released from on board, and prepare each slip so that the short end is the one let go: it has the least chance of snagging. Move fenders to where they will be most useful during the departure.

Offshore wind. The boat will blow clear of the berth and should not need springs. Rig bow and stern slips. Either slip the bow line, let the bow blow off to the required angle, slip the stern line and motor away; or slip the stern line first to let the stern blow clear, followed by the bow, and motor away.

Leaving a finger berth. It is sometimes necessary to get the stern into clear water before reversing away, to stop the fenders popping out or to counter an onshore wind. A bow spring will take the stern away from the pontoon: brief the crew; rig the bow spring and stern line as slips; place a fender near the bow; slip and recover the stern line; engage ahead with the helm towards the pontoon until the stern comes away; engage neutral, then astern; slip the bow spring and reverse out.

Onshore wind with stream. An onshore wind usually requires a spring to prise the boat off, and the direction of the stream decides which spring to use:

• If the stream is from astern, use a bow spring: engage ahead to swing the stern out into the stream, select neutral then astern, slip the spring and reverse clear.
• If the stream is from ahead, use a stern spring: fender the quarter, engage astern to swing the bow out into the stream, select neutral then ahead, slip the spring and motor away.

Springing the stern out (then reversing out), in general: rig a fore spring (from the bow, aft to the pontoon) as a slip line, doubled back so it can be released from on board. Put a fender right forward. Motor gently ahead with the rudder towards the pontoon. The bow is held and the stern swings out. When the stern is well clear (about 45 degrees), go astern, slip the spring and reverse away, then motor clear.

Springing the bow out (then going ahead): rig an aft spring (from the stern, forward to the pontoon). Fender the stern quarter. Motor gently astern. The stern is held and the bow swings out. When pointing well clear, go ahead and slip the line.

Choose which end goes out first by which way the stream and wind will help, and by prop walk.

Leaving a raft. It is normal to slip out of a raft downstream, so that the stream helps close the raft up again. Before you leave, the boats outside you need new lines ashore: a new stern line is led ashore round the stern of the departing boat ready to be hauled in, the departing boat's shore lines are removed, and when she has left the outside boat's crew pull themselves back alongside and make fast. The boat inside you remains securely moored throughout.

Stern-To and Bow-To Mooring

Many harbours around the world berth boats bow-to or stern-to a quay, with an anchor or a line to a mooring holding the yacht off the quay. Stern-to gives easier access ashore but less privacy; before choosing it, check that there are no rocks close to the quay that could damage the rudder.

Stern-to with the anchor. Rig two stern lines and fender both sides and the transom. Prepare the anchor. Reverse towards the berth and drop the anchor three to four boat lengths from the quay, snub it (check it) about half a boat length out, then attach the stern lines, windward first, and tighten in on the anchor cable until the boat lies the right distance off.

Bow-to with a kedge. Prepare the kedge anchor at the stern and make sure its rope is tied on. Fender both sides. Drop the kedge three to four boat lengths from the quay as you motor in, snub it half a boat length out, attach the bow lines (windward first) and tighten in on the kedge.

Lazylines. Some harbours provide lazylines secured to an underwater mooring instead of using an anchor. Prepare two bow (or stern) lines and fenders; the lazyline is picked up from the quayside on arrival with a boathook and led to the far end of the boat, and the two lines secure the end nearest the quay.

Wind effects. In an offshore wind the stern seeks the wind on the approach, so drop the anchor in the centre of the berth, four boat lengths out, and reverse slowly towards the quay. In an onshore wind the anchor, once dropped, holds the bow head to wind; either ease back on the chain or reverse in. In a crosswind keep momentum so that the boat does not drift to leeward; you will initially lie alongside the downwind boat, then warp into position.

Picking Up a Mooring Buoy

Under power

1. Look at how other moored boats are lying: they show you the combined effect of wind and tide. Make a trial run past the buoy to check the depth and the direction of wind and stream.
2. Approach from downstream, heading the same way as the moored boats, so you can stop with the buoy at the bow. If stream is present, always moor into the stream.
3. Brief the bow person with a boathook and a mooring line, and to use hand signals (point at the buoy, show the distance with fingers), because the helm will lose sight of it under the bow.
4. Stop with the buoy alongside the bow, on the windward side so that it does not go under the boat. Hook the pick-up line or thread a line through the ring, and make it fast to a bow cleat. If staying, rig a second line or a proper strop.
5. Never put a hand or foot between the boat and the buoy, and never try to hold the boat with the boathook.
6. To leave, rig the line as a slip (both ends on board), drop back or motor gently off on the side away from the buoy, then slip, watching for the line round the propeller.

Under sail

Wind and stream must both be taken into account, and their directions differ from one buoy to the next. The RYA method is to decide which sail to use by sailing past the buoy into the stream with both sails let fly: whichever sail will not spill its wind is the one to take down, and you approach under the sail that will spill.

• Wind with stream (from the same direction). Approach on a close reach under mainsail, using the stream as a brake and easing the sail to slow down. In light winds both sails may be needed.
• Wind only (no stream). Sail up to the buoy on a close reach under mainsail, easing the sail to slow down.
• Wind against stream. The mainsail would not spill, so drop it and approach downwind into the stream under headsail alone, controlling speed by furling most of the sail away or dropping it. Slewing the boat across the stream, one way and then the other, also strips speed off.
• Wind across the stream. Start slightly further upwind to compensate for leeway and slow by furling or partially dropping the headsail.

The close reach strategy. A close reach is the approach angle that lets the mainsail be eased (spilled) to slow the boat and filled again to speed up. On a beam or broad reach the main cannot be eased enough to spill the wind; too close to the wind and you may not make the buoy. To judge the angle when there is little stream, sail past the mooring with the wind just aft of the beam, tack, and your final approach will have the wind just forward of the beam. If the yacht has enough power, furl the jib to clear the foredeck. Start slightly upwind of the direct line to allow for leeway, get the buoy in transit with a fixed object, and to spill the sail ease the mainsheet fully and drop the traveller to leeward; to fill it, grab the falls of the mainsheet and lean back. Pick the buoy up on the windward side.

A flapping sail slows the boat but can injure the crew and makes communication impossible; a furled or partly lowered headsail slows the yacht with more control. Practise on a fender before attempting it on a real buoy.

Anchoring under sail

Anchoring under sail is easier than sailing to a buoy, because the anchor is dropped when the boat comes to rest rather than at a precise point. Give a clear brief and make a trial run to check the depth. With wind and stream together, approach on a close reach into the anchorage, spill wind and steer into the wind until the boat stops, drop the anchor and ease back as required, release the kicker and take up the topping lift to depower the main, and when the anchor has set and a transit has been checked, lower and stow the mainsail. With wind against stream, drop the headsail or sail upwind, lower and stow the main, bear away under headsail at slow speed into the stream, drop the anchor and slew the boat so that the stream pushes her back and sets the anchor.

Worked Example

Scenario

You are skippering a 34 ft yacht with a right-handed propeller and three crew (one experienced, two novices). The forecast is southwest 4 to 5, gusting 22 knots in the afternoon. You leave a marina in the morning and must return to a starboard-side-to berth in the evening with a 1 knot stream running along the pontoon from bow to stern (ahead of the boat as berthed) and the wind blowing off the pontoon.

Departure

The wind is light in the morning. You single up to a bow line, stern line and slip springs, with the short ends to be slipped, brief the crew, and leave going astern. Prop walk pulls the stern to port, which you planned for by turning the bow to starboard first so the stern swings towards the fairway. Steerage astern only comes once you have about 2 knots through the water, so you keep a hand on the throttle and a firm grip on the wheel.

Sailing

Before leaving you looked at the forecast and the white horses outside the breakwater and hoisted with the first reef already tied in, following the RYA guideline that 16 to 20 knots means one reef and three-quarters of the headsail. At 1300 the true wind reaches 20 knots and the boat heels to 25 degrees, with heavy weather helm. You put in the second reef: head up to close-hauled, ease sheet and kicker, take the weight on the topping lift, drop the halyard to the mark, hook on the tack, re-tension halyard, haul in the clew line, re-trim, sail tie through the clew. You roll in about half the genoa and move the car forward two holes. The heel drops to 15 degrees, the helm lightens and boat speed is the same.

You notice the upper genoa telltales lifting before the lower ones. Diagnosis: too much twist. Fix: car one more hole forward. Now they break together.

Return

Your berth is starboard side to with the stream running from your bow towards your stern. Because you must stop into the stream, you approach heading into it, which is the right direction for this berth. The wind is off the pontoon, so the bow will blow away as you slow. You:

1. Make a trial run past the berth to see the stream on the pontoon piles and the wind on the flags at the marina office.
2. Approach at about 30 degrees, slightly faster than in calm conditions to hold the bow up against the wind, but stopping by the stream rather than by reverse, judging speed over the ground by the piles abeam.
3. Do not use astern to stop, because prop walk would pull the stern away to port.
4. Get the midships line ashore first and take it to a cleat aft of the boat's midpoint; with the engine ticking ahead and the helm turned away from the pontoon, the boat is held alongside.
5. The crew then secure bow line, stern line and springs.

Safety When Sail Handling

• Clip on in any seaway, at night, when alone on deck and when working on the foredeck or at the mast. Work on the windward deck when heeled, and close the companionway hatch.
• A clutch or cleat under load can release suddenly, so never stand in line with a loaded rope.
• Keep the sheets clear of feet and keep winch handles out of the winch when not grinding.
• Before a manoeuvre, check people are clear of the boom and the mainsheet traveller line.
• Wear a lifejacket with a crotch strap and a light, and wear gloves for handling heavy rope.
• When reefing in strong winds, bear away to reduce apparent wind if you can. A boat sailing downwind at 6 knots in 25 knots true wind feels about 19 knots apparent; head to wind and the apparent wind is 31 knots.
• Never put a hand or foot between the boat and a pontoon, wall or buoy.

Exam-Style Tips: What the Assessor Expects

• Brief the crew before every manoeuvre: who does what, which line, what the abort signal is.
• Explain your decision: "I am reefing now because the apparent wind has risen to 20 knots and we are heeling 25 degrees".
• Plan the berthing or buoy approach by wind and tide, make a trial run, and state the plan aloud, including the escape route.
• Use springs and slip lines and keep fenders ready on the right side.
• Demonstrate each manoeuvre calmly and slowly. Assessors reward control, not speed.
• Know the direction of your boat's prop walk and say how you will use it.

Common Mistakes

The diagram lists the most frequent errors and their fixes.

Click to zoom

• Reefing too late. Fighting a flogging sail in 30 knots injures crew and damages sails. Reef early, and before leaving harbour if the forecast says so.
• Ignoring telltales. They give instant feedback; use them every time you change course or the wind shifts.
• Getting the telltale fix backwards. Windward lifting: sheet in or bear away. Leeward stalling: ease or head up.
• Reducing only the headsail in a blow. It increases weather helm. Reef the main.
• Down-tide berthing. Without the stream to brake you, you arrive too fast. Turn and approach up-tide.
• Applying power before turning the rudder in a tight space, so the prop wash is wasted.
• Not testing reverse and not knowing the direction of prop walk. Find out before you are in a tight space.
• Too much speed in the marina. Arrive no faster than you would be happy to hit the pontoon.
• Crew jumping ashore. Step off when the boat is alongside; never jump a gap.
• Slip lines rigged with the long end to be let go, which snags on the cleat ashore.
• No briefing and no trial run. Every manoeuvre needs a plan, roles, an escape route and an agreed abort signal.

Summary

• Sails are wings: set the angle of attack by easing until the luff lifts, then trimming in until it stops.
• Telltales show airflow; windward lifting means sheet in or bear away, leeward stalling means ease or head up.
• Use sheet leads, traveller, kicker, outhaul and cunningham to add power in light airs and flatten and depower in strong winds.
• Choose the sail plan before leaving: reef and change down early, because it is easier to add sail than to take it off.
• Slight weather helm is good; excessive weather helm means heel too much, too much main, or reef needed.
• Reef early, with a briefed crew, on a close-hauled course or hove-to, and reinforce the clew with a sail tie.
• Heave-to by backing the headsail, easing the main and lashing the helm to leeward.
• Under power, turn the rudder before applying power, know your prop walk, pivot points, steerage speed and windage, and approach into the stronger of wind and stream.
• Read the stream from moored boats, piles and weed; judge drift and speed with transits, not the log.
• Berth into the stream at a shallow angle; ferry glide into tight berths; avoid downstream berthing; use long warps and a fender board against a wall.
• Springs and slip lines control a boat alongside and let you leave a wind-on berth safely; bow spring if the stream is from astern, stern spring if from ahead.
• Moor bow-to or stern-to with the anchor dropped three to four boat lengths out, windward line first.
• Under sail, approach a buoy on a close reach under the sail that will spill, into the stream, and pick up on the windward side.
• Brief the crew before every manoeuvre, make a trial run, and abort early if it is going wrong.

Check Your Understanding

1. Upwind, the windward headsail telltales are lifting. Give two ways to fix it.

Answer: Sheet the headsail in, or bear away a few degrees. The sail's angle to the wind is too small.

1. Which way should you move the genoa car if the top telltales break before the lower ones, and why?

Answer: Forward. The top of the sail is twisting open too much; a forward lead pulls the leech down and closes the top.

1. In a gust, what is the quickest way to reduce heel and weather helm on the main without changing sail shape?

Answer: Drop the traveller to leeward (or ease the mainsheet). The main keeps its shape but meets the wind at a smaller angle.

1. The forecast is 18 to 22 knots and you are about to leave harbour. What sail plan do you set before hoisting, and why before rather than after?

Answer: First reef in the main and about three-quarters of the headsail (second reef and half the headsail if it is already blowing 22). Reef before hoisting because it is far easier to shake out a reef than to put one in at sea, and the harbour is usually more sheltered than the conditions outside.

1. List the key steps of slab reefing in order.

Answer: Head up (close to but not into the wind) or heave-to, ease sheet and kicker, take boom weight on the topping lift, lower halyard to the mark, hook the cringle on the ram's horn, winch the halyard tight, winch in the clew pennant with the sail flapping, ease topping lift and re-trim, put a sail tie through the clew and around the boom, tie in the loose sail with reef ties around the sail, not the boom.

1. How do you heave-to?

Answer: Tack leaving the headsail sheeted on the old side so it is backed, ease the main partly, and lash the helm to leeward (tiller to leeward, wheel turned to windward).

1. Why should you turn the rudder before applying power in a tight space, and why does the rudder not work going astern until the boat is moving?

Answer: Going ahead, prop wash deflects off the angled rudder and turns the boat in a smaller space. Going astern the prop wash does not flow over the rudder, so steering depends entirely on water flow from movement astern.

1. Your yacht has a right-handed propeller. Which side to will be easier to berth, and which way is it easier to turn in a confined space?

Answer: Port side to, because going astern to stop, prop walk pushes the stern to port, towards the pontoon. Turning to starboard is easier for the same reason: the burst astern walks the stern to port and helps the turn.

1. You are pinned onto a pontoon by an onshore wind with the stream from astern. How do you leave?

Answer: Use a bow spring rigged as a slip line, fender the bow, motor gently ahead with the rudder towards the pontoon so the stern swings out into the stream, select neutral then astern, slip the spring and reverse clear. With the stream from ahead you would use a stern spring and swing the bow out instead.

1. What is ferry gliding, and when is it used?

Answer: Stemming the stream so that the boat is stationary over the ground (checked by a transit abeam), then steering slightly towards the pontoon so that the stream on the angled bow crabs the boat sideways into a tight berth under full control. Used whenever a stream is running along the berth.

1. How do you decide which sail to use when approaching a mooring buoy under sail, and which side of the bow do you pick it up on?

Answer: Sail past the buoy into the stream with both sails let fly: the sail that will not spill wind is taken down and you approach under the one that will. Wind with stream: mainsail on a close reach. Wind against stream: headsail, running down into the stream. Pick the buoy up on the windward side so it does not go under the boat.

1. You are mooring to a harbour wall with a 4 m tidal range. How long should the warps be, and what else must you check?

Answer: About three times the range, so around 12 m, rigged so that they can be adjusted from the boat. Check there is enough depth at low water, rig a fender board or horizontal fenders against the piles, and make sure the mast and spreaders cannot touch anything as the boat rises and falls.

1. Describe how to berth stern-to a quay with the anchor.

Answer: Rig two stern lines, fender both sides and the transom, prepare the anchor, reverse in and drop the anchor three to four boat lengths from the quay, snub it half a boat length out, attach the stern lines windward first and tighten in on the anchor.

1. You approach a pontoon down-tide at 5 knots over the ground. What should you do?

Answer: Abort, turn and approach up-tide, into the stream, so the boat can be held with little speed over the ground. Speed over the ground matters, not speed through the water; check it with objects abeam.