Want to understand better how to manoeuvre a yacht under power? Yachtmaster Instructor, Rachael Sprot walks through her most important rules for handling under power When handling under power is done well, it\u2019s like a black art. It wasn\u2019t until I became an instructor that I realised it could be broken down into a few key concepts. I called them \u2018The 10 Golden Rules of Boat Handling\u2019. However, when I wrote them it was largely from the perspective of a heavy displacement yacht with fine ends, using a shaft drive. Most of the large yachts I\u2019ve sailed in the past 10 years, such as the Clipper and Challenge yachts, matched this profile.
\nRecently, I\u2019ve realised that the rules need updating. Yacht design has moved on considerably, and sail drives, long waterlines, bow thrusters and high topsides are now the norm, and twin rudders are increasingly commonplace.
\nFlexisail, which operates a fleet of modern cruisers, kindly lent me the keys to Varvassi, a Hanse 418, for a day last winter to refine these Golden Rules, and in this two-part series I\u2019ll explain how to make manoeuvring under engine so much easier.
\nThere are two elements to good boat handling: understanding the boat\u2019s handling characteristics; and understanding the external factors which impact a manoeuvre. In the first of this series we\u2019re going to look at how a boat behaves, and next month we\u2019ll consider the real-world scenarios we find ourselves in.
\nKeep it as slow as you can when manoeuvring in tight spaces \u2013 things then go wrong more slowly and you have more time to make corrections. Photo: Paul Wyeth
\nRule 1: Slow is pro
\nThe number one rule of boat handling, especially on large yachts, is that if it\u2019s all going wrong, go wrong slowly. You\u2019re unlikely to do much damage at 1 knot. At 3 knots things become expensive. There are times when a burst of power is necessary and, carefully applied, this is an important tool. However, panic revs can cause more problems than they solve. If in doubt, step away from the throttle and pick up a fender \u2013 just use the throttle to maintain slow control.
\nMinimum speed is essential on a heavy boat which carries its way. Once moving, many manoeuvres can be done in neutral. However, the Hanse 418 didn\u2019t hold her way as much as I expected so I had to be more assertive on the throttle, both to keep her moving and to stop her.
\nA burst of prop wash flowing over the rudder while the boat is stationary creates \u2018Type 2\u2019 steerage. Photo: Paul Wyeth
\nRule 2: Maintain steerage
\nThe counterpoint to Rule 1 is that you always need steerage. Steerage is created when water flows over the rudder. There are two ways of achieving it which I call Type 1 and Type 2 steerage.
\nType 1 is what you experience when you\u2019re actively propelled through the water, either by the engine or the wind. It\u2019s easy to forget that the wind can still be used for propulsion, even without sails up. If you\u2019re doing a downwind park (perhaps into the tide), or have some way on, you might not even need the engine in gear to achieve Type 1 steerage.
\nType 2 steerage is what is generated when a burst of prop wash flows over the rudder while the boat is stationary. This is an effective technique for tight turns when you need to control the direction of the boat without covering any distance.
\nIn a lighter boat like the Hanse, Type 1 steerage is more effective than Type 2. Under way, Varvassi\u2019s high-aspect spade rudder was extremely efficient. She was responsive in both ahead and astern. However, there was less response from a power burst. This is probably due to the saildrive, which positions the propeller further from the rudder and creates a delay between action and reaction.
\nI suspect also that the high aspect rudder profile, though powerful when making way, can\u2019t \u2018catch\u2019 as much of the jet created by the propeller. I\u2019m no hydrodynamicist, but a big barn door of a rudder seems to make better use of this thrust. It felt like Type 1 steerage was much more effective than Type 2 steerage in this modern design of boat.
\nPhoto: Ludovic Fruchaud\/EYOTY
\nTwin-rudder variation
\nIf the boat has twin rudders, Type 2 steerage is nearly impossible to achieve. The propeller sends water straight between the two, missing the rudders entirely. You\u2019ll need to keep the boat moving faster in order to maintain steerage and predict what the boat will do until the rudders have gained steerage.
\nRule 3: Gear then steer
\nI once overheard a watersports instructor coaching teenagers in a RIB. \u2018Steer, then gear, Henry!\u2019 he exclaimed, too late, as they drifted into a raft of dinghies.
\nHenry looked crestfallen, but he\u2019d demonstrated that RIBs and other outboard-powered vessels work the other way round to most sailing yachts. In displacement boats with rudders, the rule is: gear, then steer.
\nIn a tight spot every centimetre counts and there are gains to be made from following this simple rule of timing. In a heavy displacement yacht change gear from ahead to astern (or vice versa) first but don\u2019t change the way you\u2019re steering until the boat has actually started moving and water is flowing over the rudder in the desired direction.
\nThis is particularly important when switching from ahead to astern since it takes longer for the boat to stop and water flow to reverse over the rudder. From astern to ahead the steerage switch is more immediate because the prop wash hits the rudder before the boat has started moving, negating the reverse flow sooner.
\nVarvassi was quicker to regain steerage after a gear change than a more traditional, heavy displacement yacht. The power bursts were less effective but, once moving, steerage was quickly established. It gave me more confidence to change gear in a confined space which, in turn, changed the kinds of manoeuvres I might attempt.
\nVarvassi has negligible prop walk with her saildrive, so on a boat like this make wider turns and keep up momentum. Photo: Paul Wyeth
\nRule 4: Use your prop walk
\nI\u2019ve learned to love prop walk over the years. The sideways push from a burst astern is like having a stern thruster, albeit in one direction. With a propeller shaft, the steeper the angle, the greater the kick will be.
\nBoats with skeg-hung rudders often have offset prop shafts too, which induces even more kick one way or the other. On a shaft drive boat I tend to think of it as being right- or left-handed. A boat that kicks to port in astern is right-handed and favours a turn to starboard, and vice versa.
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\t\t\t\t\t\t\tHow to handle heavy weather<\/p>\n
\t\t\t\t\t\t\tOn Tuesday 15 June 2021 our Swan 48 Isbjorn was positioned near 51\u00b0 North, some 350 miles south-west of Fastnet\u2026<\/p>\n
\t\t\t\t\t\t\tHow to: navigating in tide<\/p>\n
\t\t\t\t\t\t\tWherever we have current (tidal or other) this will always influence the sailing wind and the boat\u2019s course over the\u2026<\/p>\n
Many shaft-driven boats will turn in a boat length if you utilise a few short bursts of astern propulsion, just enough to boost the stern around but not enough to get going in, and establish, reverse steerage. This shapes your manoeuvres. In confined spaces a right-handed boat is best positioned on the port side and is easiest to park portside-to, since the prop walk draws it in that way, and creates an escape route by making room for a starboard-hand turn. There are times when this is thoroughly inconvenient, but if you plan your manoeuvres with prop walk in mind it\u2019s largely a blessing rather than a curse.
\nVarvassi had very little prop walk thanks to the saildrive whose propeller sits vertically rather than tilted downwards as on a shaft drive, so the thrust comes off more cleanly. Furthermore, a saildrive is located further forward, so has less leverage around the boat\u2019s pivot point. I found that a traditional tight turn method isn\u2019t effective on a yacht with a saildrive, and would be even more difficult on a twin rudder boat.
\nIn such cases, a bow thruster would be a really useful tool. Without one you\u2019ll need to keep the momentum and stay in forward gear, but the turn will be wider. Or make a three-point turn by turning hard one way, then reversing back into the space you\u2019ve come from, reversing the steerage too and bringing the bow around in reverse.
\nConsider how the pivot point of the boat moves in ahead and astern, and beware turning too sharply with a boat with wide beam carried right aft. Photo: Paul Wyeth
\nRule 5: Use the pivot point
\nUnderstanding the location of a boat\u2019s pivot point is important for any close quarters handling. However, the pivot point is hydrodynamic and changes with the direction of travel. Going ahead it\u2019s just behind the mast; going astern it shifts aft to somewhere around the cockpit, and during acceleration it shifts further to each extreme.
\nIn forward gear we need to be aware of how much boat is behind the pivot point. In reverse it\u2019s the bow we need to watch. It\u2019s important to remember this when dodging an obstruction you\u2019re being set onto. Once the pivot point is past the obstruction you need to turn towards, and not away from it, to keep the rest of the boat clear.
\nVarvassi\u2019s full-width stern is a bit like manoeuvring with a pantomime bustle: the danger is not just where you\u2019re looking, it can be behind you. The bigger the boat, the bigger the bustle. To exit a berth I sprang the bow out and drove away with a straight rudder. It took much longer to get clear enough to turn the helm away than it would on a fine-ended yacht.
\nBringing it all together
\nIn reality, there\u2019s a complex relationship between the boat and its environment. However, when you\u2019re skippering a new boat it can be helpful to isolate handling behaviours by practising in benign conditions. Is that twitch on the bow when you go astern the result of prop walk? Or was it a gust of wind? Understanding steerage, gear changes, prop walk and pivot points allows us to respond with more precision.<\/p>\n
If you enjoyed this\u2026.<\/p>\n
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Want to understand better how to manoeuvre a yacht under power? Yachtmaster Instructor, Rachael Sprot walks through her most important rules for handling under power When handling under power is done well, it\u2019s like a black art. It wasn\u2019t until … <\/p>\n