P1 BLADE, BODY, BOAT The Physics of Paddling I March 11 /July 14 1
Blade [the paddle in water]
Paddlers transmit body power through the paddle blade to move their boat. As positive pressure is generated on the powerface, partial vacuum is created on the backface, the differential forces, called thrust, drawing paddle, paddler and hull through the water
Trial and error by marathon, sprint and whitewater racers indicates 8.5” +/- .25” is the optimal paddle blade width. Wider requires more reach to work over the canoe side, narrower doesn’t hold enough pressure.
Blades need to be shaped with relieved shoulders to work under the hull and rounded tips to allow less than perfect catches as the blade is inserted for each stroke. Reinforcing ribs should be faired into the paddle faces; straights requiring balanced camber on power and back faces to slice accurately. Bents are seldom sliced due to lower stance in the boat and shorter shafts, and do not require face camber.
The paddle blade is an inefficient propulsion device. It provides cyclical power in pulses and it can lose purchase by fluttering, allowing water to stream off its surface and by ventilating, sucking air down its backface to compromise thrust. Attention to the neck, where blade and shaft meet and shaft length will reduce ventilation.
As J Winters proved in ~1990, paddles are most effective when +/- 10 degrees of square to the stroke and significantly less effective at angles much beyond the +/- 10 dg “Winters Window.” The rowing/sculling community selects 20 dg. Averaging those numbers leaves us at a +/- 15 degree window. Functional paddlestrokes are always shorter than commonly performed. Carrying the paddle aft of the body and past the “Winter’s window” compromises efficiency as well as adversely affecting a hulls direction. Art/Pic 1
The paddle is most efficient and predictable in powering paddlecraft when the shaft is either vertical for forward, back, and abeam strokes or horizontal for sweeps and reverse sweeps. A vertical paddleshaft requires that the paddlers grip or top hand be outside the hulls’ maximum beam at the paddler’s station. Stacking our hands, the top hand directly above the shaft hand, requires significant torso rotation, more than most of us commonly use. Positioning the top hand inside the rail introduces a horizontal component, transforming forward strokes into sweeps that turn the boat. Similarly, carrying the blade aft of the body rsults in sweeping force that turns the boat away from paddleside. Art/ Pic 2
The stroke itself must be parallel to the hulls keel, not its rail. Paddling along the rails, in bow, center or stern paddling stations adds a sweeping component to forward strokes forcing the hull into yaw and turning the craft off course. Art / Pic 3
Paddle selection; Straight or bent, determines where the +/- “Winter’s window” occurs in any given stroke and when the stroke becomes ineffective and should be recovered to a successive stroke. With straight paddles square to the “window” forward of a kneeling paddler’s knee, and end just aft of it for sitters. Bent paddles square to the window from the sitting paddler’s knee to mid thigh. Bends are usually 12 dg after decades of experimentation; close to the “windows” edge for draws and pries. Tripping paddlers carry bent and straight for fatigue relief. Art/ Pic 4 The bent being used to change range of muscle motion and when higher cadence usefully improves speed. The straights 2 usually employed when maneuvering is important.
The paddlers hold on the paddle is also key; both hands should be loose. A loose shaft hand allows significant forward extension of the catch. Comparing loose lower grip with a shaft hand death grips suggest invcreased forward placement of the catch by almost a foot. Similarly, tight top hands reduce the paddler’s ability to pitch the blade.
Body [bio-mechanics / the paddler in the boat]
Paddlers should use large muscles to increase power and endurance, specifically the Latissimus dorsi, Posterior Deltoid, Triceps, Teres, Trapezius, Rhomboid, and the longitudinal spinal muscles loosely grouped as the ribeye.
To utilize these muscle groups that are mostly in the back, paddlers should use their arms as struts, locking them in a partially bent position. Torso rotation engages the back muscles in powering the stroke, and increasing forwards reach to the catch.
Paddler stance in the boat can enhance or compromise biomechanical output. Standing
or high kneeling engages the leg muscles, provides the greatest range of motion and
keeps the paddleblade square to the stroke longer. They are also the least stable stances in the boat, with elevated Center of Gravity, [CG]. Bone to boat contact is
through knee and foot or feet.
Kneeling with the knees in the chines and butt on a seat provides a more stable stance with CG well inside hull and still engages the legs to power forward strokes and improve both rotation and forward reach. Both knees provide bone to boat contact, transferring power from the body to the boat and also improving stability. The straight blade paddles’ Forward Stroke squares into the “15 Degree window” completely forward of the knee. Kneeling with a bent is more restful than using a straight because forward reach is reduced, and speed increases with the higher cadence the shortened reach and shaft allows, but directional control is compromised with the bent because the power pulse is further aft along the hull and thumbs down correction is less effective with bent blades because they are often outside the “Winters window” by design.
Sitting reduces torso rotation, reach and stability. The paddler rotates from the seat up while balancing on narrowly spaced sitz bones. While CG is lower, the bone spread increases the rate of roll so stability is lessened. A footrest or foot pegs are needed to provide bone to boat contact for balance and force transfer.
The reduction in rotation means that sitting paddlers are unable to reach far enough forward to square straight blade paddles to the stroke. The use of bents, which square into the “window” alongside the paddler’s thigh, are more efficient than straight blades for sitting paddlers. Shortened rotation and reach can yield higher cadence and thereby higher fprward speed. The reduced effectiveness of the bent’s thumb down correction also encourages higher cadence and switching sides to control yaw. Higher cadences tend to require smaller paddleblades for speed through the water and to reduce injury.
Recoveries need to be horizontal and feathered, the blade carried forward to catch position with ample torso rotation and relatively stiff arms. In-water recoveries increase drag, slow cadence and may misdirect the hull.
3
The relaxed, reclining, position assumed as paddlers lean into backrests compromises rotation, reach, power and directional control, but is appropriate for birding, fishing, photography and reading.
Boat [the hull in water]
A quiet boat is an efficient boat. Yawing off course, sideways roll, and fore to aft pitching all disrupt smooth water flow along the hull, increase drag and slow the canoe.
Biomechanics may need to be compromised to keep the hull quiet; specifically lunging to an extremely forward catch and allowing a longer forward stroke may cyclically pitch the hull bow down, causing drag through disruption of waterflow along the hull. Over reaching over a wide hull’s side to present a vertical paddleshaft may start cyclical side to side rolling, that will disrupt smooth waterflow along the hull, slowing the boat and decreasing stability. Failing to keep cadence will induce rolling and yaw. It is better to miss the top grip and complete the next stroke with top hand on the shaft than disrupt cadence. Yawing off course increases hull crab and tends to skid the stern, bot disrupting smooth flow along the hull.
Hulls can be heeled to one side or the other to lift the stems and increase rocker, tightening turns. Pitching the hull bow down for forward turns further increases skid rate. Heeling and pitching upright helps stop rotation, but all these movements must be smooth to minimize waterflow disruption over the hull surface.
All this suggests shorter forward strokes within John Winters Window for SUP Boards, Canoes and Kayaks. Cadence destroying Corrective Maneuvers especially the J Stroke, should be minimized and switching sides, or cross forward strokes for kneeling soloists, is the preferred method of course correction, with the knowledge that such need indicates Forward Stroke problems. Wind, Waves? pick up cadence and speed to, stuff/pin the bow in the water. The stern generally follows.
Attention to the Paddleblade Physics, Bio-Mechanics and the Boat in the water allow us to paddle more efficiently, farther and faster with less effort. Not a bad idea as few of us are getting younger.
[There is More.]
© Charlie Wilson
Blade [the paddle in water]
Paddlers transmit body power through the paddle blade to move their boat. As positive pressure is generated on the powerface, partial vacuum is created on the backface, the differential forces, called thrust, drawing paddle, paddler and hull through the water
Trial and error by marathon, sprint and whitewater racers indicates 8.5” +/- .25” is the optimal paddle blade width. Wider requires more reach to work over the canoe side, narrower doesn’t hold enough pressure.
Blades need to be shaped with relieved shoulders to work under the hull and rounded tips to allow less than perfect catches as the blade is inserted for each stroke. Reinforcing ribs should be faired into the paddle faces; straights requiring balanced camber on power and back faces to slice accurately. Bents are seldom sliced due to lower stance in the boat and shorter shafts, and do not require face camber.
The paddle blade is an inefficient propulsion device. It provides cyclical power in pulses and it can lose purchase by fluttering, allowing water to stream off its surface and by ventilating, sucking air down its backface to compromise thrust. Attention to the neck, where blade and shaft meet and shaft length will reduce ventilation.
As J Winters proved in ~1990, paddles are most effective when +/- 10 degrees of square to the stroke and significantly less effective at angles much beyond the +/- 10 dg “Winters Window.” The rowing/sculling community selects 20 dg. Averaging those numbers leaves us at a +/- 15 degree window. Functional paddlestrokes are always shorter than commonly performed. Carrying the paddle aft of the body and past the “Winter’s window” compromises efficiency as well as adversely affecting a hulls direction. Art/Pic 1
The paddle is most efficient and predictable in powering paddlecraft when the shaft is either vertical for forward, back, and abeam strokes or horizontal for sweeps and reverse sweeps. A vertical paddleshaft requires that the paddlers grip or top hand be outside the hulls’ maximum beam at the paddler’s station. Stacking our hands, the top hand directly above the shaft hand, requires significant torso rotation, more than most of us commonly use. Positioning the top hand inside the rail introduces a horizontal component, transforming forward strokes into sweeps that turn the boat. Similarly, carrying the blade aft of the body rsults in sweeping force that turns the boat away from paddleside. Art/ Pic 2
The stroke itself must be parallel to the hulls keel, not its rail. Paddling along the rails, in bow, center or stern paddling stations adds a sweeping component to forward strokes forcing the hull into yaw and turning the craft off course. Art / Pic 3
Paddle selection; Straight or bent, determines where the +/- “Winter’s window” occurs in any given stroke and when the stroke becomes ineffective and should be recovered to a successive stroke. With straight paddles square to the “window” forward of a kneeling paddler’s knee, and end just aft of it for sitters. Bent paddles square to the window from the sitting paddler’s knee to mid thigh. Bends are usually 12 dg after decades of experimentation; close to the “windows” edge for draws and pries. Tripping paddlers carry bent and straight for fatigue relief. Art/ Pic 4 The bent being used to change range of muscle motion and when higher cadence usefully improves speed. The straights 2 usually employed when maneuvering is important.
The paddlers hold on the paddle is also key; both hands should be loose. A loose shaft hand allows significant forward extension of the catch. Comparing loose lower grip with a shaft hand death grips suggest invcreased forward placement of the catch by almost a foot. Similarly, tight top hands reduce the paddler’s ability to pitch the blade.
Body [bio-mechanics / the paddler in the boat]
Paddlers should use large muscles to increase power and endurance, specifically the Latissimus dorsi, Posterior Deltoid, Triceps, Teres, Trapezius, Rhomboid, and the longitudinal spinal muscles loosely grouped as the ribeye.
To utilize these muscle groups that are mostly in the back, paddlers should use their arms as struts, locking them in a partially bent position. Torso rotation engages the back muscles in powering the stroke, and increasing forwards reach to the catch.
Paddler stance in the boat can enhance or compromise biomechanical output. Standing
or high kneeling engages the leg muscles, provides the greatest range of motion and
keeps the paddleblade square to the stroke longer. They are also the least stable stances in the boat, with elevated Center of Gravity, [CG]. Bone to boat contact is
through knee and foot or feet.
Kneeling with the knees in the chines and butt on a seat provides a more stable stance with CG well inside hull and still engages the legs to power forward strokes and improve both rotation and forward reach. Both knees provide bone to boat contact, transferring power from the body to the boat and also improving stability. The straight blade paddles’ Forward Stroke squares into the “15 Degree window” completely forward of the knee. Kneeling with a bent is more restful than using a straight because forward reach is reduced, and speed increases with the higher cadence the shortened reach and shaft allows, but directional control is compromised with the bent because the power pulse is further aft along the hull and thumbs down correction is less effective with bent blades because they are often outside the “Winters window” by design.
Sitting reduces torso rotation, reach and stability. The paddler rotates from the seat up while balancing on narrowly spaced sitz bones. While CG is lower, the bone spread increases the rate of roll so stability is lessened. A footrest or foot pegs are needed to provide bone to boat contact for balance and force transfer.
The reduction in rotation means that sitting paddlers are unable to reach far enough forward to square straight blade paddles to the stroke. The use of bents, which square into the “window” alongside the paddler’s thigh, are more efficient than straight blades for sitting paddlers. Shortened rotation and reach can yield higher cadence and thereby higher fprward speed. The reduced effectiveness of the bent’s thumb down correction also encourages higher cadence and switching sides to control yaw. Higher cadences tend to require smaller paddleblades for speed through the water and to reduce injury.
Recoveries need to be horizontal and feathered, the blade carried forward to catch position with ample torso rotation and relatively stiff arms. In-water recoveries increase drag, slow cadence and may misdirect the hull.
3
The relaxed, reclining, position assumed as paddlers lean into backrests compromises rotation, reach, power and directional control, but is appropriate for birding, fishing, photography and reading.
Boat [the hull in water]
A quiet boat is an efficient boat. Yawing off course, sideways roll, and fore to aft pitching all disrupt smooth water flow along the hull, increase drag and slow the canoe.
Biomechanics may need to be compromised to keep the hull quiet; specifically lunging to an extremely forward catch and allowing a longer forward stroke may cyclically pitch the hull bow down, causing drag through disruption of waterflow along the hull. Over reaching over a wide hull’s side to present a vertical paddleshaft may start cyclical side to side rolling, that will disrupt smooth waterflow along the hull, slowing the boat and decreasing stability. Failing to keep cadence will induce rolling and yaw. It is better to miss the top grip and complete the next stroke with top hand on the shaft than disrupt cadence. Yawing off course increases hull crab and tends to skid the stern, bot disrupting smooth flow along the hull.
Hulls can be heeled to one side or the other to lift the stems and increase rocker, tightening turns. Pitching the hull bow down for forward turns further increases skid rate. Heeling and pitching upright helps stop rotation, but all these movements must be smooth to minimize waterflow disruption over the hull surface.
All this suggests shorter forward strokes within John Winters Window for SUP Boards, Canoes and Kayaks. Cadence destroying Corrective Maneuvers especially the J Stroke, should be minimized and switching sides, or cross forward strokes for kneeling soloists, is the preferred method of course correction, with the knowledge that such need indicates Forward Stroke problems. Wind, Waves? pick up cadence and speed to, stuff/pin the bow in the water. The stern generally follows.
Attention to the Paddleblade Physics, Bio-Mechanics and the Boat in the water allow us to paddle more efficiently, farther and faster with less effort. Not a bad idea as few of us are getting younger.
[There is More.]
© Charlie Wilson
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