Oars – They’re not sticks, they’re springs – by Howard Aiken

Most club rowers, quite rightly, will work with whatever equipment they are given, so we sometimes miss the subtleties of design in that equipment.  Take a modern sweep-oar for example. It is actually a highly-engineered precision instrument designed maximise the efficient transfer of mechanical energy from rower to boat, so to get the best out of them it helps if you understand its characteristics.bendy

In mechanical terms, each oar or blade on a moving boat is a second class lever with the fulcrum (centre of rotation) near the tip of the spoon.  However, while it is correctly described as a lever, a blade is not rigid. It is designed with a carefully calculated degree of flexibility.

From the rower’s point of view the importance of this flexibility is its relationship to the effort (energy) the rower is applying to the blade.  At the start of a stroke (the catch) the blade is subject to a bending force as the rower pulls the handle toward the bows.  The spoon remains almost stationary in the water, moving the boat forward by means of the force which is transferred to the boat at the pin.  As the blade bends it is in effect storing energy which will be released again as the blade unbends.  So the important question is – when does the blade unbend? There are only two options:

Option 1. The blade unbends as the spoon lifts out of the water.  In this situation the rower is pulling hard on the blade as her outside hand moves downward to extract the blade.  There is still pressure on the front face of the spoon as it leaves the water.  At its worst this is referred to as “washing out”, where the spoon doesn’t actually stay in the water for the full length of the drive phase but moves up and out of the water, creating a telltale “wash” of foam as it leaves the surface, rather than the puddle we should expect. In less severe cases it still produces a splash at the extraction – a sure sign that energy is being wasted in throwing water into the air rather than moving the boat.

Option 2. The blade unbends in the water.  In this situation the rower has slightly eased off the pressure on the handle at the finish.  As the blade unbends, the energy stored within it is transferred to the boat as forward motion. There will be little or no splash at the end of the stroke as the blade is extracted from the water because there is no pressure left on the front of the spoon to throw water into the air.

In practice there is only a small fraction of a second’s difference between option 1 and option 2, but that small fraction of a second can deliver a significant improvement in efficiency. Leaving the spoon in the river for that extra moment allows the rower to convert the energy stored in the blade into additional forward motion.  Over the duration of a race, that additional motion could be the difference between winning and losing.  In my experience, once rowers learn to think of the blade as a spring rather than a stick and to look critically at their extraction technique for signs of splash or wash, they can significantly improve the efficiency of their stroke, getting a little more boat speed for a little less effort by making better use of the flexibility that the designers of modern blades have gone to so much trouble to provide.

Incidentally, all of the above also applies to sculling, although being shorter in length, most sculling blades will not bend as visibly as a sweep blade during the stroke.

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Know your Centre of Rotation.

Luckily, just beside my rowing club, a road bridge crosses the river.  One can stand on that bridge and watch boats pass underneath.  I actually advise our beginners to do this, because rowing as seen from the rower’s point of view and rowing as seen from a bridge above the river differ in several key respects.

From the rower’s point of view, the catch is taken behind his or her seat i.e. with the spoon toward the bows of the boat while they are at frontstops. During the power phase of the stroke, the spoon moves past the rower toward the stern until the rower reaches the finish and the blade is extracted at the end of the stroke.  If you ask most rowers to pinpoint the blade’s centre of rotation, the point around which they are working to apply force to the blade they will probably point to the pin. (The pin, in case some readers don’t know, is the vertical post at the end of the rigger on which the swivel turns).

From the bridge, the view is rather different.  It is a view dominated by the motion of the boat as it comes towards us.  Looking down, we can see that as the blades enter the water at the catch they appear to ‘lock’, remaining stationary in the water as the boat continues past them. The angle between blade and boat changes with the forward motion of the boat and as it does so the spoon makes a small movement outward, away from the boat so that the tip of the spoon is furthest from the boat as the blade passes through the 90 degree right angle. Once that point is passed, the tip of the spoon moves back toward the boat as it moves on, before the blades are extracted from the water. There are some good diagrams to show this movement here: www.concept2.co.uk/blade-path .

The first 20 seconds of this video clip (the 2014 Boat Race seen from Hammersmith Bridge) also illustrate the movement:

Video credit to Pier Paolo Ciarravano at http://www.larmor.com/

Which brings me to the point of this blog. To the rower, the centre of rotation appears to be the pin at the end of the rigger. From the rower’s point of view it may therefore seem sensible to bury not just the spoon but a couple of feet of the loom in the water during the power phase of the stroke, because if the pin is the centre of rotation then all that additional surface area in the water is helping to transmit the rower’s awesome power to the water and hence increasing the speed of the boat. In reality, the centre of rotation is close to the tip of the spoon and every part of the blade inboard of that point is moving in the same direction as the boat. Spoon and loom are therefore subject to the very considerable ‘drag’ of the water which has to be pushed out of the way to allow for that motion.

As its name implies, ‘drag’ is THE big negative of the sport of rowing. It is the water’s resistance to the movement of a solid body and most boat designers spend most of their time trying to minimise it, because it is the single biggest energy drain on a boat in motion. Designers measure the ‘wetted area’ of a hull because they know that the more surface area they have in the water the more drag they have on the boat.  I apply the same logic in coaching rowers.  Having too much blade in the water – whatever else it may do – creates significant drag.

Rowers need to understand that their centre of rotation is out beyond the pin, at the tip of the blade.  When they understand that, they can understand how to use the blade efficiently.  I ask them to respect the designers who have crafted their blades to float with the top edge of the spoon at the surface of the water and the loom out of the water and I run drills to get rowers to treat the catch as part of the recovery rather than part of the stroke – dropping the blade onto the water and feeling its bouyancy rather than rowing it forcefully into the water and burying it.

There is of course another school of thought which recommends ‘rowing deep’ with the spoon and much of the loom in the water (there is a discussion here for example:  groups.google.com/forum/rec.sport.rowing) and certainly if you watch elite scullers, most use more blade in the water than I am recommending here. Does this change my view?  No, it doesn’t and for the following reason.  Elite scullers have to use equipment which complies with the same rules as the rest of us.  However, they are applying far greater force in the water with that equipment than even a good club or university rower.  That amount of energy applied to a sculling blade at normal depth would disrupt the ‘normal’ hydrodynamics of the spoon – they would in effect lose their grip on the water during the power phase of the stroke.  They therefore have to row deeper to enable the blade to deliver their much greater power to the water.  The trade-off in terms of increased drag is one they are happy to accept as they are still moving the boat faster than they would do at the shallower depth.

The temptation to row ‘like an elite rower’ is understandable, but unless you’re also going to train like an elite rower, it is about as productive as strapping on an 80 pound backpack for a hiking weekend so that you can march ‘like a Marine’ (http://www.royalmarines.uk/carrying-a-heavy-bergen).

Taking the brakes off – five ways to speed up your boat

I’ve written previously about the innovative work done by the GB Cyling team on the importance of marginal gains and how this might begin to translate to rowing  (http://bit.ly/1ihUbYO) .  It is as true in rowing as in any other sport that important races are often won or lost by inches, so any legal change which offers even small improvements in performance is worth considering.

In this blog, I’m going to touch on four aspects of rowing technique or crew selection which any crew or coach can check on to make sure that they are getting the best boat speed they can for the effort they are putting in. Perhaps because it is easier to see these issues from outside the boat than inside it, or because crews can sometimes settle into a particular way of rowing to correct some other problem, these training points are by no means confined to beginners or novice boats.

  1. Blade depth.  Some crews aquire the habit of rowing ‘deep’, with both the spoon and a significant part of the loom below the surface of the water.  Each submerged loom creates a ‘bow-wave’ as it moves through the water and the drag caused by the bow wave acts as a brake on the boat. (See http://bit.ly/1huDCF5 for more detail).  The crew are therefore wasting precious energy on  making these waves rather than moving the boat.  Get the crew to understand that a) the blade naturally floats with its upper edge above the water b) they can reduce the depth of the blade during the drive phase if they focus on dropping the blade gently onto the water before they start the stroke c) if they pull through the drive phase with the blade floating at its natural depth the stroke feels much lighter, because the blade is being used more efficiently.
  2. Dragging blades.  Novice crews often aquire the habit of dragging their blades across the surface of the water from the finish back to the catch.  This helps stabilize the boat, reducing the amount of roll, which is reassuring for inexperienced rowers. However, the drag created by eight blades sliding across the water surface, while not as great as the bow-waves referred to above, is still hundreds of times greater than the drag created if they were in the air. [Hint to coaches: My experience is that asking the rower to lower his or her hands on the recovery doesn’t usually work when seeking to correct this error.  Telling them to lift the spoon off the water is far more effective.   As the Americans would say – “Go figure”].
  3. Speed into frontstops.  The dynamics of boat acceleration are complex and it is a fact that as the crew leaves backstops on the recovery, the boat actually accelerates as kinetic energy is transferred from rowers to boat.  However if the rowers hit frontstops hard – rather than decelerating into frontstops – boatspeed is checked, because the rowers (who weigh much more than the boat) are moving in the opposite direction to the boat.  A good cue for rowers is the sound made by the wheels of their seat.  If the sound is a rising note as they move through the recovery then they are accelerating into frontstops.  If the sound is a falling note then they are decelerating into frontstops.  A smooth deceleration into frontstops followed by the smallest instant of stillness as the catch is taken and the drive begins, is the most effective way to conserve boat speed.  This of course is much easier said than done when working at race pace.
  4.  Cox’s weight. I would advise all crews training for competition to train with as much weight in the boat as possible.  If this includes a coxwain who weighs 90 kilos or more then so be it.  For the races themselves, however, minimum weight in the boat has to be the rule.  Racing with a cox who weighs 20 kilos more than the coxes in the other boats cannot in my view be a competitive advantage, no matter how good a cox he or she may be.  Having a choice of competent coxes is of course a luxury unavailable to many crews, but if you do have a choice, use the lightweight cox for competitions.

There is a fifth issue affecting many club boats but which is not an aspect of rowing technique or crew selection – and this is hull blemishes.  I remember when I was being coached in sculling, my coach put a single bungee cord around the hull of my single scull.  I was shocked by force of the braking effect it produced, simply by disrupting the smooth flow of water over the hull.  If there are blemishes which you can feel on a hull when you run your hands along it, get them repaired and smoothed out before the regatta season gets under way.  They are costing you far more boat speed than you imagine.

Taken together, the marginal improvements in performance offered by each of these changes can add up to the difference between winning and losing.  If you want an introduction to the role of marginal gains here is a short video here: http://bit.ly/SrWeQy

 

First time in a boat – Coaching a first sculling session

My first water session for scullers tends to be very different from the first water session for rowers. Whereas the rower will have spent some time on the rowing machine and in a rowing tank to get used to the basic stroke sequence and body posture of rowing, the first – time sculler gets none of this preparation.  The reason for this is that in a single scull, learning to balance the boat (i.e. learning how to avoid capsizing) is such an overwhelming priority that everything else has to wait until this basic skill has been addressed.

The key message in the first and subsequent sculling sessions is: ‘keep your hands at the same height’.

In sequence, the techniques I coach are:

  1. Getting into the scull
  2. Sitting the scull level
  3. Body posture and core stability
  4. Slowly raising and lowering each hand to see the scull’s response
  5. Confidence-building exercises based on (3)
  6. Arms-only strokes (very light pressure)
  7. Spinning the scull (backing down / pulling on, first on one side then alternately).

This is usually quite enough for a first session of 60 – 90 minutes – possibly shorter for juniors.  The level of concentration required to stay upright in a single scull is a surprise to many new scullers and can be quite tiring. The good news is that confidence rises quickly as the sculler gets used to the feel of the boat and learns appropriate responses to it’s movements.

One of the most important lessons is to move SLOWLY, especially when the unexpected happens.  Rapid instinctive responses which are entirely appropriate on dry land are usually the quickest route to a capsize on the water.  In my view, a good coach will focus on building ‘attentive confidence’ first and range of movement second.

Blade depth

Whether you are sculling or rowing, your blade is your second point of contact with the river (the first of course being the boat). The purpose of this post is to highlight an aspect of blade design which seems to escape many newer rowers and scullers.  If you hold a blade horizontally over the water at about the height of your rigger and then lower it into the water you will notice that it floats.  If you square it, it will float with the top edge of the spoon just above the surface and the loom above the water.  This is not an accident.  Blades are designed to float at the correct rowing depth – the depth at which they are most efficient, supporting the pressure of the stroke in the water while minimising the amount of resistance offered to the forward motion of the boat.

This is important because many rowers develop a habit of burying the spoon and a good part of the loom into the water at every stroke.  This produces a heavy feeling in the drive phase of the stroke which they mistake for the weight of the boat.  Allowing the blade to float at its natural depth during the stroke makes the same stroke much lighter – the difference being the resistance of the ‘bow-wave’ raised by the loom in the water due to the forward movement of the boat.  The difference can be so marked that some rowers feel they are somehow “not working hard enough” when they first make the change to using the blade at the correct depth.  The truth is that they are actually working much more efficiently and more of the effort they are applying is moving the boat because the ‘drag’ exerted by the blade is greatly reduced.

That said, getting a rower to learn how to ‘float’ the blade can be time-consuming if they have developed a habit of ‘pulling deep’.  They have to re-learn taking the catch by letting the blade fall gently onto the water under its own weight and ‘locking’ the blade at the correct depth as they start their drive.  As so often in rowing, this means they have to take a step back to make a bigger step forward.  They need to break the catch into two parts, first feeling the buoyancy of the blade before beginning the drive from the legs.  It only takes a little practice for most rowers to master this technique if they concentrate on it during drills – although it can take longer to break the habit of pulling deep during normal rowing.

One of the benefits for rowers of correcting blade depth is an easier extraction and tap down,  resulting in better balance.  Scullers may not see this benefit if they are pulling deep with both blades and it is very noticeable that many elite scullers bury far more of the blade than good technique would dictate.  It may simply be that the force these scullers are capable applying makes the additional drag less significant, or that a deeper stroke is in less danger of an uncontrolled ‘rip through’ (where the blade loses its hydrodynamic stability in the water) at the pressures they are applying.  Any elite sculling coaches out there care to comment?

Boat Types – The Pair

While undoubtedly one of the more demanding boat types, the pair deserves to get more use than it does at most clubs. It is an excellent learning environment for intermediate rowers, although having a change of kit ready is recommended for the first couple of outings.

pair01

The pair can be an unforgiving boat to row, requiring good crew co-ordination from the outset. Its main benefit as a coaching platform is that every move the rowers make is reflected immediately in the performance of the boat. Hand heights, timing, stroke length and quality of bladework all have immediate and very clear effects. If you are new to rowing a pair, just getting the boat well-balanced and moving smoothly will teach you a lot about what you are doing wrong and how well you need to do it to get it right. Getting it right is always a rewarding experience in rowing – it is particularly so in a pair. The benefit to the rower lies in taking the improved technique and performance gained in the pair back to larger crew boats where you can now be a better and more adaptable rower.

Note to coaches: A pair is likely to feel heavy to rowers used to fours and eights, so it is probably a good idea to lower the gearing on the blades. 116cm inboard is a good starting point, but don’t hesitate to give a more inboard leverage if the height / fitness / skill of the crew makes it necessary. It may also be a good idea to move the foot-stretchers further toward the bow than the rower is used to, in order to move more of the work behind the pin.

Boat Types – The Quad

The Quad is a sculling boat for four scullers with eight blades. For reasons of economy, most clubs will actually use a coxless four with sculling riggers rather than the lighter, purpose-built quad, as they then effectively get two boats for the price of one. Purpose built quads are less sturdy than fours as they are not subject to the asymmetric loads of sweep-oar rowing – so they can’t be rigged as fours.

quad01

A sculler actually has more spoon area in the water during the stroke than a rower with a sweep oar. As a result, quads have a more rapid acceleration off the catch than other boats – even when using the heavier coxless four shell. For the crew, this can present some challenges, as the rapid acceleration of the boat after the catch can result in a loss of pressure toward the finish if the crews hands don’t maintain the acceleration from the leg drive. From the coach’s point of view a quad crew are effectively rowing a two-part ‘legs-hands’ stroke – both of which need to be powerful but need to connect smoothly together. People who have learned to row before they learn to scull will probably feel slightly rushed during the power phase of the stroke as the hands and arms have to accelerate into the finish in a way that is unlike sweep oar technique. Feathering is different too, with both wrists dropping sharply as the blades leave the water at the finish, with the handles held lightly in the crooked fingers well above the palm.

While the sculler at bow is in charge of steering and usually has a foot-operated rudder control, he or she will usually recruit the rest of the crew to help with steering. A boat as fast as a quad often needs more steering than can be managed via the rudder alone and a little more right or left hand pressure from the whole crew is the safest way to navigate a busy or bendy river.

Coxed quads are used for junior (11 – 18) scullers at most clubs and offer an excellent training environment for coxes who aspire to bigger, senior boats. While not as lively as the coxless quad, the coxed quad is also an excellent coaching environment for junior scullers, able to accommodate mixed ability crews quite safely.