This Post Has 7 Comments

1. Duncan Crockford November 2, 2011 Reply

   When we were in St Catharines in 2010 for the World Masters we got chatting with a lightweight who was doing some trials with Volker Nolte. I’m pretty sure he worked at Hudson Racing but I might be wrong. If memory serves they were using Concept Fats (so no reduction in spoon size there), in a double over distances of up to 1000m. They were working on the catch and finish arcs being the important thing and finding that as they reduced outboard and tightened the span to keep the load the same, the faster they went. I’m sure he was talking about spans down to something like 154cm or even less, the main limiting factor being stability as the sculls got shorter so you can imagine how short they were going. He did say they didn’t know if or to what extent the gains might translate over longer distances and they still had a lot of work to do but from this and other conversations I’ve had over recent years it seems to me that limiting slip, optimising the arcs and reducing load by reducing outboard seems to be a good strategy to try.

2. Simon Collingridge November 2, 2011 Reply

   I’m a sculler and coach, although I am not lightweight (6′ 1″ and 90kgs).

   For me I would be concerned that using a smaller spoon could reduce the amount of lock-on at the catch and also potentially bring some slip into the power phase of the stroke. As such I would look to increase the amount of inboard (reduce outboard) and depending on the amount of additional inboard, perhaps also reduce the overall length too, or the cross over of the handles may become excessive.

   To me, a smaller spoon would be something I would look at if, for example, the sculler was having issues with clearance during the recovery, difficulty in control in windy conditions or feeling that the swing weight of the blades was causing issues.

3. Walter Martindale November 2, 2011 Reply

   Not really enough info for a full response. My initial thought is – do you have video from overhead and what sort of catch length is being obtained?
   My approach is a little unconventional – Shorten overall length, depending on how much you shorten the overall length, either keep the inboard the same or shorten it and move the feet toward the stern; row with the blade a little deeper – according to Kleshnev (personal correspondence) you want about 1/2 blade-width of water above the top edge of the blade – and a recent modeling study (yet unpublished) by Sliasas (McMaster University) has tested this versus a shallow blade and found it more efficient for reasons he hasn’t yet worked out.
   You don’t supply present oar length, inboard, or the spread on the pins.

   1. RY November 3, 2011 Reply

      Is there a way of getting that paper you mentioned? would be interesting to see how much more effective the deeper blade is and whether it is something i would introduce.

4. Denis Rabij November 2, 2011 Reply

   The answers of the more learned fellow rowers before me, already provide plenty fuel for thought, and are pretty sound. I would add, that whatever you do, “do one thing at the time” so that you can go on an outing and try compare the sculler’s own feelings with your observations. If something actually happens for the best of worse, then you arealdy know the one thing that has to stay or has to be reversed. One thing I learned in my coaching career, is that the guy/girl in the water wants you (the one on the motor-boat, bycicle, hindemburg or with the tool box) to get things done in terms of gear-rigging. So, it is always nice to do things without telling the rower-sculler “exactly” what you have done. The drill is, you tell the rower quite casually “I have fixed a thing or two in your boat” and then tell him to go rowing and try give you feedback on what he actually felt. Now, there is one derivation from that school of thought, which is … working out what exists only in the rower’s imagination. It is AMAZING how in some instances I have done that with PLACEBO (i.e., in fact I did not modify a thing on the whole rig, but went on to tell the rower that I did some fiddling) and even so the rowers would come back telling how they felt “better” about various things and in many cases, came out with better performances. Don’t show this note to your sculler! One final note. Whatever lenght your sculls are, make sure you keep the aspect ratio. This is simple, you just pick overall (say, 291cm) divide that by inboard (say you are using 88cm) it will give you 3,3068181818 which is what you want to retain throughout your re-sizing. Then say you have reduced the overall length to 288. The new inboard measure will be, 87,1cm (aprox to the third decimal) which will in turn give you the same aspect ratio as before, or the same “leverage proportion” if you will. I know this sounds pretty basic, but I have seen many people “forget” that basic step, so it sits here as a reminder. Also, if you would just retain the old 88cm, then you would be changing both “lenght” and “inboard” ! My personal preference is for big blades, which in theory would return higher stroke rates, since they require smaller overall lenghts. For my own boat I use Croker S4 with slicks blades (those without a “spine”), which I believe, is the choice of younger fellers like Mahe Drysdale. Please let us all know of your progress.

5. Carl Douglas November 3, 2011 Reply

   I’m sure others will have their own take on this, so let’s all chip in & see what comes out. Here’s my 2-pennorth:
   I see 2 underlying misapprehensions –
   1. that blade-slip is a form of gearing
   2. that you can spend too long in the water – with the equally false corollary that you raise rating by “getting the blade through faster”.

   You only propel the boat when the blades are immersed. To accomplish the same amount of work in a stroke duration of 0.7 rather than 0.8 sec, the sculler has to increase the pressure by 14.2%. Yet we all know how even slight overloading (another 5kg on the bar) brings down the number of repetitions in any gym exercise. Actually, it gets worse than that, because if the stroke arc is shortened, a greater proportion of the rower’s work is invested into the least efficient mid-section of the stroke, & the time taken to load & unload the blade also (probably) remains unchanged. So shortening an OK stroke will impair race pace or endurance. A smaller blade means, as the writer clearly sees, more slip. Any amount of slip is precisely calculable as work thrown away: slip distance x slip load = power lost from the propulsive process If we increase slip, it may feel “lighter” because the handles move faster, so we find it harder to keep them loaded, but that is gaining us nothing except comfort. Might just as well wash out or row shallow!

   Here the point to note is that a more efficient stroke, although it throws away less of the work you put in, is absolutely bound to “feel” heavier & take longer to accomplish. Why would you want to sacrifice that greater efficiency which, if used intelligently, will get you to the other end of the race either faster or for less work?

   However, that “feeling heavy” bit comes initially from the mind. Told to get the stroke done faster, either by coach or by one’s internal clock, the inevitable first response is to pull harder – so it feels heavy. But the load you feel comes not from the oar, it comes from you. The stroke is only as heavy as you choose to make it.

   Which brings us to stroke duration & rating: If the part of the stroke in (& not through, please!) the water takes 0.8 sec & you’re rating 30, you have a full 1.2 sec to go from finish to the next catch. Since most of your work is done in the 0.8 sec that the blade’s immersed, how is it difficult to reduce the duration of the unloaded airborne part? Knock that 1.2 sec down to 1.1 sec & your rating will rise from 30 to 31.6. Shave it to 1.0 sec & rating rises to 33.33. Bring air time down to equal immersed time, 0.8 sec, & rating hits 37.5. But by then, if you’ve sustained the same stroke pressure, you’ll be working 25% harder & going just 7.7% faster, so your stroke time in the water will have fallen from 0.8 to 0.74 sec, so your rate will actually have risen to 39.

   Obviously ever person has an optimum rating for the delivery of their work, although most of us pretend that it is lower than it in reality could be – due to our lousy dexterity, usually. So it can be worth experimenting with inboard/outboard proportions & spans. But rating is our first & most adaptable gearing system, & rating is controlled not by time in the water but by how little time we spend in the air between strokes.

   Low ratings require higher loads (& so they feel heavier) to deliver the same power that is attainable at higher ratings with reduced loads. That is your gearing system, just as it is on a bike. Adjust the load you apply & don’t let some inner demon kid you into increasing above a sustainable load. And do not try to change gear by increasing blade slip.

   HTH?
   Carl

6. Gerrit de Jong November 8, 2011 Reply

   Hello everybody

   Nice to see that people want to do some good thinking every now and then. Here my remarks.

   Thee very most important factor for the rower of expiriencing “load” is de distance the boat travelled during full submersion of the blade. For a good heavy men’s pair it is 2.70 – 2.85 meter. This can be realized with little segment and great leverage; little leverage and great segment, or every mix of those two. Of course the dynamic behavior in the powerstroke is influenced by the choices made for rigging.

   A to heavy load, or more specific a to high resistance and concomittantly long duration of the stroke, has a negative trade-off. The pressure in the muscles squeezes the blood out of the cappilaries. Like a sponge, the more is squeezed out, the longer the time for refilling. This gives a serious limmitation on oxygen delivery on in special the highest loaded muscles, the ones that needs the oxygen the most!

   The bigger the blade, the less the slip, the higher your efficiëncy. Of course this is only true for a fully submerged blade. There is the law of decreasing wins and gaining trouble at the catch and release towards the bigger sizes, which give limitation to the size of the blade. Prefferently choose the biggest blade you can handle and adjust rigging.
   The real point is not the size of the blade but decreasing slip. You should not have a big wake. You can decrease slip too by choosing for a big segment at catch position. This choice should depend on the type of rower and his technical skills however.

   I have some simple rules of thumb for adjusting load.
   The typical endurance type single sculler should have a sligtly bigger segment in catch position than a typical sprinter type and a little more time with the blade submerged. This is for ease of building up pressure for the slow fiber type of the endurance rower versus the faster contraction speed of the sprinter.
   Keep overlap comfortable, so always adjust span and inboard together. Little rowers should have smaller overlap than tall ones, range is 18-22 cm. Keep in mind the oarlocks gives you an extra 4 cm overlap. Span does not have significant influence on load because you always adjust your footstretcher to your rigging, and footstretcher position has significant influence opposite to span by chancing segment.
   In good weather conditions with a nice wind in head or tail direction, say 3 beaufort, maximum 4 beaufort, row in both directions at strokerate 22. the headwind should row nice, the tailwind should be a little technical challencing. If so, you have the right adjustment.

   Never fool your rower. They will know it sooner than you believe, and after that they are not going to believe you at the moment they better should do!!!!

   Best regards
   Gerrit

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