Boat Handling – Understand The Basics And Banish The Bumps!

Boat handling skills are vital for all boaters. Anyone who has helmed a boat will know that all sorts of forces combine to wrest control from your hands. An understanding of the forces involved in boat handling is central to becoming a good boat-handler, and being a good boat-handler is central to the enjoyment of boating. We go boating to enjoy the freedom of the sea, but to get there we first have to negotiate the dreaded pitfalls of the MARINA!

 For many boaters entering and berthing in a strange marina is the most stressful part of a passage. And no wonder. They have just left the peace and quiet of the wide oceans for a noisy, confined haven full of shiny and very expensive yachts, each with a cockpit full of boat-handling experts. There are coachloads of tourists sitting on the quay wall licking ice creams and watching every move like judges waiting to score your boat handling performance. The wind is pushing from behind, the tide is swirling through the pontoons and that nice lady on the marina's VHF, who clearly doesn’t realise that this boat has a mind of its own in reverse, has allocated a berth at the end of a narrow, dead-end fairway.

It doesn’t have to be like that. As with most aspects of boating, planning and understanding of the forces involved, plus the application of a few basic techniques, will turn those nightmares into daydreams and take the stress out of your leisure time. Soon we’ll take a look at the forces at work on a moving boat and ways of turning those forces into additional controls. But first lets re-cap on the basic controls that we employ.

How rudders work

Our first control surface is the rudder, often unseen beneath the hull. Like all hydrofoils they must have a flow of water passing over their blades in order to work. In the absence of any waterflow – say drifting dead in the water – you have no control. But, the moment a waterflow is established you can steer, and the faster that waterflow becomes, the more powerful a rudder will be. So the skilled boat handler isn’t constantly watching his or her hands on the wheel but has a clear mental picture of the rudder position and the flow of water passing over it. With the rudder set at an angle, the flow of water is deflected and ‘lift’ is created, resulting in the stern of the boat swinging to one side.

The second control – the propeller – produces thrust that’s used to drive the boat forwards or backwards. But, more importantly when using forward thrust, it will make steering more effective by accelerating the waterflow over the rudder blade.

By accelerating the flow briefly, using short bursts of thrust, you can take advantage of the rudder without moving the boat significantly forward. With the rudder to one side, a quick burst of the throttle in forward gear will kick the stern sideways before the thrust overcomes the boat’s inertia sufficiently for it to creep ahead. Keeping the wheel or tiller on full lock to one side you can use short bursts of thrust, first forward then in reverse, to turn the boat around its pivot point (somewhere around the leading edge of a sailboat’s keel) in little over its own length.

So, it’s important to understand that you don’t need waterflow over the whole hull to steer – just the rudder blade will do. A good boat handler will always understand where the rudder is set and use the first burst of thrust against that pre-set rudder to start the boat turning immediately in the required direction.

Single screw motorboats also have their propellers and rudders well aft so will behave similarly. However, they don’t have fin keels so their natural pivot point is much further aft.

In forward gear the propeller is working at maximum efficiency, accelerating the waterflow over the rudder, so you have lots of control, even at very low boat speeds. In reverse, however, the propeller isn’t so efficient, prop walk is maximised and prop thrust is directed away from the rudder, so control depends entirely on the flow of water over the rudder generated by the boat’s movement through the water. The rudder will also be unbalanced moving in reverse, so keep a firm grip on the wheel or tiller.

Going astern

The transition from forward to reverse leaves you temporarily out of control with no waterflow over the rudder. So, If you need to reverse into a tight space, it helps to give yourself a long run up to allow plenty of room, firstly to achieve steerage way and secondly to get a really good feel for how the boat is handling on the day.

Think about what’s happening to the rudder as you select reverse gear. Firstly the prop thrust is directed away from the rudder and then the boat slows, reducing waterflow over the rudder to zero and robbing you of all control. Then the boat will start to move slowly through the water, this time in reverse. When reverse speed has built to say, one knot, you will feel the rudder biting and regain steering control, but that transition period may take ten seconds or more and while you are going through it wind, current and prop kick will conspire to take control of your boat.

So to get through the transition from forward to reverse successfully, give yourself plenty of room and, if the boat doesn’t do as it’s asked as you regain control, go forwards again, set the boat at a different ‘attitude’ to the elements and have another go. Good luck.

To steer a boat we need a flow of water over our rudder and we need ‘steerage way’ to deal with all of the other effects – the wind, etc. If we turn our boat into the stream we can be at a standstill relative to the ground (and all of the objects fixed to it) with the waterflow over our rudder giving us complete control. By contrast, if we turn downstream, we will find ourselves ‘dead’ in the water with zero flow over the rudder and, therefore, no control as we approach any fixed objects at the speed of the current. This is not a happy situation so there really is no question that, when manoeuvring towards fixed objects such as mooring buoys or quay walls, ALWAYS approach into current.

Ferry gliding

You can harness the force of the tide or current current to move a boat sideways. For centuries, ferrymen have been using the stream to take the effort out of crossing rivers. Basically, if a boat is set at an angle to the stream and is driven slowly forward then the forward vector will combine with the current vector to produce a sideways movement. If the boat’s angle to the current is reduced and the speed reduced, then the sideways speed will also reduce. If the boat’s angle to the current is increased and the speed increased then the sideways movement will increase. Ferrygliding is an extremely useful technique and most helmsmen will use it to a greater or lesser extent whenever they are operating in a strong current or tide.

Harnessing the wind

Think about the underwater profile of the average sailing cruiser. There’s very little immersed area from the bow back to the keel but from there on back, there’s lots of resistance to lateral movement. This means that in a cross-wind situation we should expect our bows to blow away downwind first.

Make use of momentum

Prop walk or paddle wheel effect

Most modern cruisers, with sail drive units placed fairly well forward, don’t suffer significantly from this effect, but just about every othe single screw vessel does. The effect is caused by energy spiralling off of the tips of the propeller as it spins, and results in a movement of the stern to one side or the other that is most noticeable when starting to go astern. Find out which way your boat kicks and then plan for it. For example, if you know that your boat kicks to port when you go into reverse then start the manoeuvre with the stern to starboard of your intended course. Generally speaking the kick can be accentuated by surging the engine revs and reduced by reducing the revs. Of course, the kick stops altogether with the engine in neutral.

Learn to love your prop kick and use it to your advantage. If say your boat has a pronounced kick to port you can make positive approaches to a ‘port side to’ berth knowing that a burst of astern thrust will both stop the boat and swing the stern into the dock, squaring you up nicely. Also, when turning in close quarters choose a turn to starboard so that a burst of reverse thrust will slow the forward movement and swing the stern out to port making for a very tight turning circle.

Go slow and keep your eyes peeled for trouble

The first advice that most instructors will give novice boat handlers is to operate slowly in confined waters. Sensible enough but, of course, the effects of nature – the drift caused by wind and current – will be most keenly felt when moving at slow speeds. Our waters are rarely still. Wind and current will combine to produce a drift in some direction other than straight ahead, so you must expect it and remain alert. Look for the signs. When looking ahead watch for fixed objects ‘transiting’. And keep looking to your right and left to make sure that you don’t drift too close to other boats etc.

Stern encounters

Sailing cruisers don’t drive around corners like a car. They pivot around their keels. In fact, because rudders are placed under or near to the stern of a boat, we really steer by swinging the rear end away from the direction that we want to turn. It stands to reason, therefore that we must always allow room for that movement of the stern or we compromise our ability to steer at all. So stay in the middle of fairways. Don’t swing too wide when turning into berth, particularly if you are turning into a current and the natural drift is downstream. It’s particularly important when approaching an alongside berth, between other moored boats. If you approach at too shallow an angle and are too close to other moored boats you will compromise your ability to steer.

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