Boat Handling under Power

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As soon as you install a propeller on a boat, you enable her to do two things which she cannot do under sail. She can make way for an unlimited period into the eye of the wind or in no wind at all, and she can stop more quickly than ever she could by virtue of the natural forces which otherwise prevail. It so happens that these two items are often critical, particularly the former. They enable an indifferent power-assisted seaman to succeed where the finest sailor in the world could resort only to warping his vessel into her berth.

It is easy to drive a boat under power. To drive her well is another matter altogether, though doing so need not involve virtuoso performances. Indeed, all that most of us would ever ask is to be able to slide so quietly into our berths that no one on shore notices our arrival, and our crews never realise quite how it was done. What then happens to a boat when she is under power?


Unlike a motor vehicle, a boat is not guided by the movement of anything at her front end. Whatever force is making her turn, as we have seen when discussing sail balance, she pivots about her centre of lateral resistance. This is just as true under power as it is under sail. It means, amongst other things, that if your vessel is lying alongside a dock you will never work her off it tidily by shoving the helm over and motoring ahead. Before her bow can swing out, her stern must swing in. Somehow, the bow must be persuaded to come off the wall. Pushing off is the obvious way but there are others which we shall explore later.

If the yacht is moving ahead and you need to steer close around an obstruction, or avoid an imminent collision, it is vital to remember the question of pivoting. Many buoys or piles have been struck by the stern of a vessel as her helmsman turned her helm the wrong way, thinking that he was steering away from it, when all the time he was swinging the stern inexorably into danger.

Blowing off

When you bring a yacht to rest beam-on to the wind, her bow will invariably blow off downwind, as the boat pivots around her keel (Fig 6.1). How fast or how

Fig 6.1 Turning. When a yacht turns, she pivots around her keel: the bow goes one way and the stern the other.

far this happens varies from boat to boat, but you can bank on it with complete certainty.

With the boat moving well through calm water there will be no discernible tendency to blow off except in the hardest cross-winds because the keel is biting the water and doing its job, just as it is when she is sailing. It is only as the vessel slows down to stalling speed that the keel loses its dynamic efficiency and the bow blows away. If you are losing way in a final approach, it's important to realise that this will happen and make any arrangements that may be necessary - either to allow for it or to counteract it - before the effects become embarrassing.

When a boat is moving ahead, the action of the rudder is obvious. On moving astern, however, the situation is less clear. Theoretically, you should stand looking aft when steering, then operate the wheel or tiller so that the rudder is pointing in the direction you want the stern to swing. As any owner of a long-keeled yacht will tell you, life is not often that simple. A fm-kccler with a deep spade rudder will sometimes steer beautifully astern at very low speeds. Sadly, some boats refuse to steer astern at any price at all. The majority will agree to a compromise, but in order to give them a chance you must bear in mind all the forces which are acting upon the boat. The rudder is only one of them.

If the propeller is placed immediately forward of the rudder (it should be, and often is), you can enjoy the benefit of being able to pivot your yacht around her turning point when she is not moving ahead at all. Put the helm hard over so that the rudder is acting as if you were going ahead. Now give her a solid blast full ahead for a few seconds. Unless she is very light, the yacht won't gather any appreciable way, but the surge of water thrown aft by the propeller will be hurled out sideways by the rudder blade. The stern will be thrown in the opposite direction.

Because propellers arc situated abaft the rudder in only the rarest of cases, this effect cannot be reproduced by giving the engine a burst astern. None the less, a strong kick in reverse will usually shunt the stern of a boat predictably one way or the other, but it is the propeller which is doing the work, not the rudder. The phenomenon goes under various names. We shall refer to it as 'propwalk'.

Rudder effect

Checking over the side for prop wash with engine astern and boat tied up securely - one of the surest ways of spotting the throw of the propeller.

Propeller effects

Water being driven off a revolving propeller comes away in a spiralling vortex. At all times this creates a certain amount of sideways force, though it becomes negligible when the boat is moving ahead above stalling speeds. When she is not under way, the results arc noticeable and sometimes dramatic, particularly with the engine in reverse. Ahead, they are always masked by the effect of the rudder; astern, the rudder is ineffective until some speed has been built up, and even then the blade does not react on the water being thrown from the propeller.

If you have the more common 'right-handed1 propeller, you will find that when the engine is put astern, the stern of the yacht will shunt across to port, and vice versa with a left-handed prop. On some craft this can be so positive that it becomes a primary manoeuvring tool; in others it is barely perceptible. What you need to determine by experiment is which way the stern will go and how hard.

The best means of finding this out is to run the engine astern while you are tied up. A glance over both quarters will be enough to indicate on which side the turbulence is greatest. Freed of the dock, the boat would naturally shimmy her stern away from the disturbance.

If you forget to find out while you are still in your berth, steer straight ahead in calm water, put the engine out of gear and let your way fall off. When you are nearly stopped, but before your head starts blowing about, put the propeller half astern and observe in which direction the boat tries to swing. Once you've stitched up the details of your propwalk, you have gone a long way to producing tidy power handling.

Moving ahead

If you want to turn tightly when you are moving ahead you have two choices: either you make the turn while carrying way or you do it with the gears engaged and the propeller throwing water over the rudder blade. The latter will generate a shorter turning circle - the more power on, the smaller it will be - but since you will probably find your vessel accelerating as you go round, you'll need good nerves if you are surrounded by expensive yachts. Should you 'bottle out' halfway round you may not make it, but carry on regardless and the bill will be heavier if your judgement proves shaky. The power turn is not for the fainthearted, but in competent hands it can be a problem-solver.

The set piece short turn

Sometimes a need arises to spin a vessel in her own length, or not much more. If your boat is unusually athletic and you are of the sort of disposition which peers unflinchingly into the cannon's mouth, you may still get away with a power turn, particularly if you can arrange your affairs so that she is swinging with the propeller. Most times, such a bold approach is better turned down, either to ease the strain on your heart or, more usually, because the yacht simply won't swivel tightly enough without help. In either case the answer is the short turn (Fig 6.2).

• Decide whether to turn to port or starboard. This will be determined by which way your stern goes with the engine in reverse. If the stern shunts to port, you should set up to turn the boat to starboard, or vice versa.

• Having decided which way you're going, position the boat so as to capitalise on what space is available.

Let's now assume that you have a right-handed propeller and that the yacht therefore wants to make her turn to starboard, with her stern swinging to port:

• Put the rudder hard to starboard (tiller to port) and leave it there.

• Give the engine a strong burst ahead. The stern will swing to port and her head to starboard.

• As soon as she shows signs of gathering way, put the engine into neutral, then into astern (gently - be kind to the gearbox). Run it at about half revs, and watch the propwalk pull her round. Unless you are proposing to gather stern-way in order to reposition the boat, you won't need to move the rudder (to do so could well be counterproductive). It isn't the rudder that is turning the boat when the engine is astern like this, it is the propeller.

• Watch the ship's head carefully. When the rate of swing diminishes, give her another few seconds ahead (duration: several seconds).

Fig 6.2 The short turn, a Rudder hard over. A long burst ahead throws the stern as propwash hits the rudder, b Going astem to prevent gathering way. Propwalk maintains the swing of the stern. (Note - there is no need to move the rudder under normal circumstances if the yacht has a strong propeller torque.) c Another burst ahead, dTurn completed.

• Repeat as necessary until you are round. Practice works wonders for perfecting this manoeuvre.

Motoring astern

As we've noted already, some vessels do this readily while others seem determined to refuse. Generally, the longer the keel, the more difficult steering becomes when you are going the wrong way. The same, incidentally, holds good if you arc trying to sail backwards (sternboard) with your mainsail held aback by a muscular crew member. Moving astern successfully brings all your skills into play. You need to be aware of whether or not the yacht's head will try to blow off, and if so, whether this effect will work with or against your propwalk. Propwalk is the over-riding consideration. It affects all boats until they have built up sufficient stcrnway for the rudder to counteract it. This can be anything from 1 to 5 knots. When it is over 3, my advice is to avoid going astern if at all possible. Once again, you need nerves like backstays to stick to your guns until you finally gain control, while an awkward gust of wind across the bows could leave you terminally embarrassed, for all your guts and bravado.

The one thing you should always be able to predict is which way the yacht will swing. You may not be able to stop her doing it, but at least you won't be disappointed, and there's another point: if you know what she'll do, you can often control circumstances to minimise, or even neutralise, the effects of her wickedness. If you know your boat will go on shoving her stern to starboard for 30 yds (27 m or so), try to give her a solid sheer the other way before you start. The two may have cancelled out by the time the rudder gets a grip. You can also sometimes turn a cross-wind into an ally, be it ever so fickle. A yacht whose stern gallops to port will try to throw her bow to starboard. When there is a stiff breeze on the starboard bow, her head will be trying to blow off to port. One force will help to neutralise the other. Try going astern in that boat with a gale on the port bow, however, and you'll spin in your own length, do what you will.



Picking up a mooring under power is the easiest of all manoeuvres. All you need remember is to head up into the tide, if there is any. If there isn't, head up into the wind. When in doubt, favour the tide.

Looking at the other boats already moored will help decide which way to approach, but make sure they are of a similar configuration to yours. A light catamaran will scuttle about head-to-wind at the same time as a deep-keeled yacht seems unaware that the breeze is blowing at all.


As with the 'under sail' chapter you will find what you need to know about anchoring in Chapter 8.

Pile moorings

Tying up between a pair of piles is a peculiarly British way of carrying on. Piles provide a stable and very safe way of keeping large numbers of boats lying fore-and-aft in the crowded, tide-swept rivers of the south.

Piles psyche out the inexperienced operator in a big way. I kept my boat on piles for years and more often than not approaching strangers would attempt to tic up to me rather than pick up the empty visitors' piles next door. I'm afraid I gave them short shrift, not because I'm a naturally unwelcoming sort of chap, but because it was unreasonable for my privacy to be invaded because of so needless a misconception. It is far easier to pick up a set of 'bare' piles than it is to raft up to some unfortunate who got there first. All you have to do is to contrive two ropes in the right places. To tie up to another boat you need at least four lines, probably six. You must rig fenders, and after all that, you must still go through the usual social nonsense: 'Mind if we come alongside you?' 'Sure, you won't be bothered if we leave at 0400 will you?'

So how do you perform this miracle on bare piles? Mirrors? The dinghy? A passing carrier pigeon? No. What you do is a running moor. Basically, this means that you drive up to the first pile, tie on to it, then drive up to the second, paying out rope from the first. When you're secured to that one as well, you shorten up aft and ease out forward until the boat is centred, and then you make fast.

Opposite Sternboarding is perfectly possible in surprisingly large yachts.

Picking up pile moorings requires careful steering, sharp ropework and good communication.

In practicc there are one or two pitfalls into which the unwary may blunder. To avoid these, use the following step-by-stcp guide to the piles (Fig 6.3):

• Files are invariably sited more or less along the axis of any tidal stream. They also carry mooring rings which can slide lip and down a large, vertical iron horse.

• Make your approach uptide, if there is any; if there isn't, make it upwind. If the wind is blowing across the piles, approach from the downwind side of the first pile.

• Prepare your lines, paying particular attention to the stern line, which must be good and long. Some people like to run the ropes through the mooring rings and back on board, so as to be ready to let go by slipping them when the time comes to leave. If this is your choice (it isn't usually mine) you'll need an even longer stern line. Nothing fouls up the whole business like running out of this vital rope. Watching people try to remember how to tic a double sheetbend as steam erupts from the skipper's ears is good value, but is rarely rewarded with a successful result. Both ropes must be flaked clear to run.

• Your best knotter should now carry the working end of the stern line, correctly led through the aft guard rails, forward to the shrouds.

• Approach the downtide pile, stop with the shrouds alongside the mooring ring.

You may feel you need a fender handy, but if you sail a black fishing boat you can forget about such finesse. It is axiomatic that you don't let this pile get abaft your boat's pivot point while the crew are working on it. If you do, the boat will swivel round, the tide will come under her quarter, and all will be lost. Your only answer then is to abort and start again.

• Keep the boat fore-and-aft with the tide while your crew ties the stern line on to the ring on the pile. If they are not threading it through and back, the best knot for this is a round turn and a bowline (see Chapter 7 to find out why).

• With the stern line secure, motor slowly to the uptide pile, stop with your lee bow alongside (lee bow because then any wind will blow you on rather than off), secure, and drop back, evening up the lines as you go.

• The job is extremely easy in a boat of any size at all but if you don't feel you can cope with the dynamics, or your crew arc all low on rope literacy, an equally safe alternative is to launch your dinghy, with the stern line aboard. The dinghy crew attach one end of this to the downtide pile in their own sweet time. You drive the yacht past it and secure her to the uptide pile, which presents no challenge at all. While you arc doing this, the dinghy comes

Fig 6.3 Pile moorings, a Uptide approach, from the downwind side if appropriate, b Hold the shoulder of the boat against the first pile and attach the stern line, c Move on to the upwind side of the uptide pile and attach the bow line, paying out slack on the sternline. d Even up the lines.

alongside and hands up the other end of the stern line. Even up when the bow is fast and that's the job.

Piles should pose no problem to a reasonably competent skipper. Anyone who chickens out by rafting up needlessly should have his club tie snipped off immediately south of the knot.

Coming alongside

Coming alongside a berth is an everyday affair for most of us, yet it's surprising how wired up people become about it. The answer is to analyse the various aspects, address each one in turn, form a simple plan of action, brief your crew carefully, then execute the manoeuvre steadily and positively. Proper use of warps is crucial to tying up alongside, so before we go any further, we'll take a look at exactly what each does, and why. The nuts and bolts of how they should be handled and made fast arc dealt with in Chapter 7.

Under most circumstances, a yacht of any size below 55 ft (17 m) or so is best tied up with four ropes (Fig 6.4). These arc the bow line (or head rope), the stern line, the bow spring (or head spring) and the stern spring. Assuming the boat is 'head up' to the tide or the wind is blowing along the dock, she will be secure enough lying to a bow line only, but she will not be tidy. She will lie bows-in to the dock, risking damage to her pulpit, and bow in general. Putting on astern line which leads away aft will do little to remedy this situation. However, if you rig a stern spring from well aft to run out parallel to the bow line she will settle back on the pair of ropes and lie sweetly beside the dock.

That is the theory. Of course, life is not so simple. She would lie adequately to the wo lines so long as the tide were very strong, or if she were left motoring astern against them. Since the former is rarely the case and the latter is an undesirable long-term state of affairs, the position can be firmed up by rigging a stern line to hold the boat back against the other two warps. Should she now ride forward, of course she will hang from the stern only and will finish up grinding her aft toerail against the wall, but this situation is neutralised by deploying a bow spring to act as a pair with the stern line.

When you are coming alongside, it is important to decide which are the first lines to run ashore. Often, in moderate circumstances of wind and tide, you will opt for bow line and stern line, then rig the springs immediately afterwards. Sometimes, however, you may opt for a 'pair'. If there is a strong stream running along the dock,

Fig 6.4 Berthing alongside: 4 ropes for 4 jobs (ends on the dockside, the slack coiled up aboard). Bow line is parallel to stern spring. Stern line is parallel to bow spring. Fenders in place.

Fig 6.4 Berthing alongside: 4 ropes for 4 jobs (ends on the dockside, the slack coiled up aboard). Bow line is parallel to stern spring. Stern line is parallel to bow spring. Fenders in place.

you will be well advised to choose bow line and stern spring. Get these ashore and secure, then let the boat settle back to them while you rig a stern line, followed, at leisure, by the bow spring. If you are in doubt about how snugly she'll lie, motor gently astern against the first pair until the stern line is rigged.

Having worked our way through the theoretical functions of warps, let's get back to the order of service for coming alongside:

• Assess wind and tide conditions on the berth to decide which way to come in. Like pile moorings, you will of course choose to arrive uptide or upwind, whichever is the stronger.

• As you come in, you may want to put your engine astern to drag off the last of your way. If this seems at all likely, bear in mind what your propwalk will do. If it is going to pull your stern into the dock, so much the better. If the contrary will be the case, be ready to check the stern with your warps, and don't use reverse at all if you can avoid it. If there is no tide and not much breeze, you should always choose to put the side to the dock which the boat naturally favours (Fig 6.5). A right-handed propeller will slide you sweetly into a port-side to berth, for example.

• Tell your crew 'which side to' you arc coming in, detail off hands for the

different jobs, then briefly outline your plan and each person's part in it. Don't make a pedantic meal of this, just tell them what's going on.

• Prepare your lines in good time, and have your crew standing by in way of the shrouds to step neatly ashore as you bring up alongside. Crew hanging around in the bows with a head-rope in their hands are doomed to disappointment, and you won't be able to see where you're going either.

• Make sure that you have at least three generously sized fenders rigged around the centre of the boat. If you have a spare, be ready with a roving fender also.

• As slowly as you can, bring the yacht into the berth. Watch transits on the dock, slip or pontoon to make sure that you are going where you think you are, just as you did when mooring under sail. If there is a strong tide, you may even be able to ferry-glide in sideways under the tightest control imaginable. As the fenders touch the dock, the line handlers should step ashore, walk crisply to the designated cleat or bollard and make fast the ends of their lines. Slack is now taken up on board, and the remaining lines rigged as soon as possible. So long as you stick to one rope for one job, with no ropes doubled up on cleats aboard or ashore, the business of tying up is simplicity itself. As soon as you err from this principle, chaos - or at best, an unscamanlike lash-up - is the inevitable result.

• If you are short-handed, rig a line from amidships as you come in, but have the others ready for action. So long as the line is in approximately the same transverse plane as the centre of lateral resistance, all will be well, unless there is a ripper of a tide. Bring the yacht alongside so that the point of attachment on board (a midships cleat, or perhaps a genoa fairlead block run well forward) is adjacent to a cleat on the dock. Step ashore and make the rope off short. That will hold the boat well enough while you run your four mooring lines out. Once the yacht is properly tied up, the short line can be retrieved.

• Sometimes you will have to raft up to one or more other vessels. If so, the conventions are clear and universally applied:

a Ask permission before coming alongside. b The most recent arrival supplies the fenders.

c Tie up to the yacht inside you, then rig shore lines (or pile ropes) to take your own weight without waiting to be asked. Very occasionally, if your boat is small compared with your host, it can make sense to lie to the larger craft's lines, but you must always ask if this will be in order. Not to do so is equivalent in rudeness to helping yourself to a stranger's beer without so much as a 'by your leave'.

Leaving an alongside berth

At the beginning of the chapter we noted that you can't just 'drive' a boat from an alongside berth. This is because if you try to steer out, the dock prevents her stern from pivoting in, with the result that you bash your stern along the dock and don't succeed. Shoving the bow off is the simplest solution to this difficulty, but this isn't always practical, particularly in strong onshore winds, or where larger yachts arc concerned. What you require is a method that falls between pushing off and hauling

Fig 6.6 Springing off. a To spring your stern off, motor slowly ahead against a bow spring, using the rudder to deflect the propwash, b To spring your bow off, motor astern against the stern spring. The position of the rudder is irrelevant, but remember that as you motor away you will be pivoting; don't grind your quarter into the dock.

Fig 6.6 Springing off. a To spring your stern off, motor slowly ahead against a bow spring, using the rudder to deflect the propwash, b To spring your bow off, motor astern against the stern spring. The position of the rudder is irrelevant, but remember that as you motor away you will be pivoting; don't grind your quarter into the dock.

the bow out using a kedge. The answer is to spring off, as shown in Fig 6.6.

Springing off involves removing all your lines except one spring line, then motoring against it so that the opposite end of the boat is levered off the wall.

To spring the bow out, motor astern against the stern spring and the bow will waltz round to seaward as if by magic. If this doesn't work, springing the stern out is even more effective. Leave the bow spring on, motor ahead against it, and turn your rudder in towards the wall as though you wanted to steer your bow in. The propeller wash is blown inwards by the rudder. The bow spring levers the stern out as well and, before you know it, you arc far enough out to let go and motor astern into open water.

Don't forget to use your fenders intelligently while springing off, and always be sure that you can let go the spring line without leaving one of your crew on the pontoon.

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How To Have A Perfect Boating Experience

How To Have A Perfect Boating Experience

Lets start by identifying what exactly certain boats are. Sometimes the terminology can get lost on beginners, so well look at some of the most common boats and what theyre called. These boats are exactly what the name implies. They are meant to be used for fishing. Most fishing boats are powered by outboard motors, and many also have a trolling motor mounted on the bow. Bass boats can be made of aluminium or fibreglass.

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  • Helen
    When vessle astuern rudder put hader starbourd is effective?
    12 months ago
  • wayne
    How to prevent propwalk?
    7 months ago

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