VIEWS: 11 PAGES: 4 POSTED ON: 8/8/2011
Towards a Taxonomy of Manoeuvre: Part 1 Michael Ketemer with thanks to Doug Gifford for suggestions and graphics. Since the object of Canadian style pad- tially hazardous craft. The only way to Manoeuvre Definitions dling is the performance of manoeuvres, sensitize others to the beauty of a canoe’s All manoeuvres can be defined in terms two questions come to mind - how many movement is to present only the move- of the following distinctions: types of manoeuvre are there, and how ment of the canoe. It is perhaps best to 1. Does the pivot point move? may they be classified? These are not idle keep stunts and paddling two separate 2. If the pivot point moves, is the path of questions. An examination of the taxon- disciplines for the time being, pending the pivot point curved? Note that if the omy of manoeuvre has implications for wider acceptance of artsy paddling for its path curves, further differentiation of the terminology used to describe man- own sake. the curves could occur at a lower taxo- oeuvre and communicate about it. Most What, then, do we mean by nomic level (e.g., spiral, cycloid, para- importantly, classification of manoeuvres ‘manoeuvre’? In the real world, there is lit- bola, hyperbola, etc.), but these taxa by their geometry provides an analytical erally an infinity of possible movements would define only the rate of curva- tool for the paddler: the geometry of a of a canoe on the two-dimensional water- ture as a new variable. manoeuvre determines the options avail- plane, so it would take quite a long time 3. Does the canoe rotate around the pivot able for application of forces to effect that for the ambitious style paddler to perform point? Geometrically, the question is manoeuvre. every possible movement. However, one expressed: is the manoeuvre a transla- This is important since perhaps the sin- should most definitely applaud this ambi- tion (every point of the canoe moves gle major cause of difficulty in learning to tion: the essential attitude of the style pad- through the waterplane an equal dis- perform a manoeuvre is the failure to visu- dler is to try to exhaust the possibilities of tance in the same direction) or is the alize in one’s mind’s eye a clearly defined the canoe for movement. motion angular (not all points of the image of the pattern of movement of the Fortunately, we can reduce the infinity canoe travel equal distances, i.e., the canoe. It is important to use easily under- of possible manoeuvres considerably—in canoe rotates during the manoeuvre)? stood, yet precise and unambiguous fact, to thirteen. By abstracting we can 4. Does the pivot rate equal the curve terms to describe a boat’s motion when define classes of manoeuvres which share rate? This differentiates between teaching, and especially when arguing the same type of motion. An example is straight lines and line pivots (no curve technique with other paddlers. Another the circle turn: it doesn’t matter whether and some pivot), curve turns and benefit of this kind of study is that it can the circle is ten metres or fifty metres in curve translations (some curve and no be seen that there are several advanced diameter, the geometry of the manoeuvre pivot) and curve turns and curve piv- manoeuvres which no-one to the author’s remains the same (and by extension, the ots (where the canoe is pivoting at a knowledge has yet performed, because placement and direction of forces different rate than it is curving). there was no easy and systematic way to required to perform the circles are similar, By examining the combinations of the conceive of them. though their magnitudes will differ). In cases given above, a table of all possible the same way, if one paddles a canoe manoeuvres can be developed. All of the The Manoeuvre diagonally it doesn’t matter whether the distinctions can be expressed as a binary A hierarchical taxonomy of manoeuvre hull is at an angle of 45 degrees or 60 opposition; either the characteristic is must firstly define manoeuvre as a subset degrees to the line of travel; each are mem- there or else it isn’t. Thus we derive seven of all possible activities performable by a bers of the same class of manoeuvre. basic manoeuvres: stationary, pivot, canoeist. Besides the manoeuvre, which is straight line, line pivot, curve translation, defined in terms of the movement of a Manoeuvre and Routine curve turn, curve pivot. canoe-shaped figure on the waterplane, We can reduce the number of possible In addition, we can further divide the there are other possible classes of things manoeuvres considerably by recognizing line and curve by the angle of the boat rel- to do in a canoe: pastimes such as sleep- that manoeuvres can be linked to form ative to its direction of travel and the ing, courtship, break dancing or diamond routines. For instance, a S-turn is a com- curve pivot by the relation of its pivot to cutting; and stunts, which include gun- pound manoeuvre comprised of an inside its curve for a total of thirteen theoretical- wale bobbing, thwart jumping, hand- turn and an outside turn linked. All man- ly possible manoeuvres. Figure 1 shows stands on the thwart, Eskimo rolling and oeuvres by definition can continue indefi- the binary table and illustrations of the the like. Although these are valid uses of nitely. The transition between man- thirteen basic manoeuvres. the recreational canoe, pastimes and oeuvres is termed the change-up. The Note that this terminology differs from stunts, however well executed, should notion of the change-up is important in standard ORCA usage, but is much more not be confused with the manoeuvre, practice, for it is at these points that the logical (ORCA terminology has some glit- which is the object of Canadian flatwater paddler must apply a different set of for- ches: why is going sideways called a dis- Canadian style paddling. Paddlers who ces on the canoe. Since the state of motion- placement, and other movements are not? think that a one-handed handstand on the lessness is defined as a manoeuvre, stops Why is there no actual turn in a stop turn bow deck is an impressive demonstration can be seen as a species of change-up. as defined by ORCA?). of ability are right: but is it paddling? Pad- So then, our basic taxonomic unit (tax- So far we have covered the motion of dlers should consider that stunts included on) is the manoeuvre. Manoeuvres can be an idealized canoe on a flat surface. In in performance merely reinforce the popu- linked by change-ups to form routines. part two we will add a paddler. lar perception of a canoe as a tippy, poten- Solo Canoe Manoeuvres Does the pivot rate equal the curve rate? Does the pivot point move? Does the boat pivot? Is the path curved? 1 no — no — stationary 2 no — yes — pivot 3a yes no no yes straight line 7c b diagonal line c sideways line 5 4 yes no yes no line pivot 5 yes yes no no curve translation 6a yes yes yes yes curve turn b diagonal curve c pinwheel 7a yes yes yes no curve pivot a: pivot rate > curve rate b curve pivot b: pivot rate < curve rate c curve pivot c: pivot direction ≠ curve direction 1 7b 6c 6b 6a 7a 2 3c 3b 3a 4 Towards a Taxonomy of Manoeuvre: Part 2 Michael Ketemer with thanks to Doug Gifford for suggestions and graphics Last issue we dealt with the forward/backward and inside/outside. forward and outside backward. To movements of an idealized canoe shape Forward and backward are easily specify a manoeuvre in the real world, on a plane. By working through a grasped descriptors. Inside and outside the use of the full manoeuvre definition binary table of possibilities, we came up can refer to three things. They can refer (e.g. inside line pivot) is required. with thirteen basic manoeuvres. to the paddler’s side in linear The thirty-seven subclasses By placing a paddler in the canoe, motion—if the paddler is moving the generated by the application of these several other directional descriptors can canoe in the direction of his/her descriptors to the basic thirteen classes be generated to describe the motion of paddling side, that motion is termed a are illustrated below and on the next the canoe in terms of the paddler’s inside sideways line. Inside and outside page. orientation in the boat. The use of these also refer to the paddler’s paddling side Any manoeuvre can move into any terms is rationalized by the fact that a in a curve: if the paddler is doing a other through a change-up. By canoe shape viewed in plan is circle with his/her paddling side on the combining maneuvres, we can construct organized around two axes, the inside of the circle, then that circle is routines. centreline and a transverse axis which termed an inside curve turn. Pivoting so Note that all “manoeuvres” divides the canoe in fore and aft. that one’s bow rotates towards one’s previously defined in the literature are Putting a paddler amidships gives us paddling side is termed an inside pivot. subsumed under these subclasses (e.g., terms for the motion of the canoe which Application of these descriptors will what the rest of the world calls a stop can be stated in terms relative to the define a number of subclasses of each of turn under this schema is a line pivot paddler’s body, which displays the basic thirteen manoeuvres, with the that changes up to a stop), and that analogous organization into quarters several directions relative to the there are several manoeuvres which (anterior/posterior and left and right) paddler in which the manoeuvre can be have not—to my when viewed in plan. performed. For instance, one can paddle knowledge—previously been defined The two pairs of descriptors which a canoe in a straight line forward or or attempted (the curve pivot). categorize manoeuvre in terms of the backward; a circle turn can be inside paddler’s orientation are forward, inside backward, outside 1: stationary 2: pivot 4: line pivot inside outside inside inside 3a: straight line 3b: diagonal line forward inside forward backward inside backward 3c: sideways line outside backward inside outside backward outside Solo Canoe Manoeuvres: Curves 6a: curve turn 6b: diagonal curve bow f o r w a r d i n si d e -in bac k w a r d o u t si d e back w a rd outside stern -i n b a c k w a r d i n si d e forw ard outside back w ard inside stern -i n f o r w a r d i n si d e bow -in forward outside 6c: pinwheel bow-in inside bow -in backward inside stern stern-in inside -in backward outside stern e -i n forward outsid bow-in outside bow- in forward inside stern-in outside e pivot b: pivot rate<curve 5: curve translation curv rate 7b: for w ar ) insid t d out ide e forwa pi v o side (backward ins rd curve/inside outs for ide ) ide fo ivot w ar d i n si ts rward curve/outside p de (back w ard o u e pivot a: pivot rate>curve ot c: pivot direction ≠ curv curv r at e ve piv e di 7a: cur r ec ≠ 7c: ti o n insid e forw ivot insi d ivot ard curve/inside p e forw ard curve/outside p outs ide fo ivot outs ot rward curve/outside p ide fo rward curve/inside piv