Showing posts with label kayak science. Show all posts
Showing posts with label kayak science. Show all posts

Tuesday, November 13, 2012

A Harbinger for an Ancient Legacy

Recently, the science of kayak hull design has taken and interesting turn which brings together aspects of the kayak and surfski into new exciting high performance craft that promises to shape the future and change the way we paddle.  In this article, I present some background information and dive into design features of the Epic 18x which I believe is the most compelling hybrid design to date.

The kayak is a remarkable invention of the Inuit people allowing them to thrive in barren, hostile lands, not otherwise suitable for habitation.   This powerful tool while bountiful with its benefits, demanded a discipline and strict set of age old skills.  Modern renditions of the kayak gave this remarkable craft to the masses and introduced them to the rich Greenland traditions and discipline.  But nothing from the past is immune to the scrutiny of science, as paddlers demanded greater performance and mastery of the seas.  As science and technology have influenced the kayak, the surfski, having come from a very different past, faced an even more profound transformation, producing remarkable paddle craft capable of achieving high speeds on the rough ocean, not only squeezing efficiency from the paddler's every stroke, but augmenting it with energy captured from the sea itself.  As the quest for kayak speed progressed, high speed flat water racing kayaks emerged, achieving high speeds, but leaving the paddler with a much less seaworthy craft as optimizations for speed sculpted away its traditional rough water handling features.   However, the kayak industry is now taking a long look at the surfski and finding ways to adopt its remarkable design elements.  Recently, one kayak manufacturer introduced an exciting new iteration of its kayak that is every bit a kayak above the waterline, but every bit a surfski below the waterline.  While new designs are common, the paddling community took notice as this new radical design achieved staggering speeds and proved itself a formidable expedition kayak.   However, as with the racing kayak, there are always tradeoffs in exchange for gains.  But, for the first time, a near hybrid design emerged, capable of being paddled like a kayak or surfski on the ocean,  casting a shadow on the pedigree of two rich and storied legacies and their legendary disciplines.

The surf ski sprouted from modern western culture along the coast of 20th century Australia.  As the populations ventured into the turbulent surf,  a need arose for a suitable lifesaving craft capable of negotiating the surf.  In New South Wales, Harry McLaren and his brother Jack in 1916 built sit atop, hand paddle boards to navigate the family's oyster beds.   Variations of these craft were later used for lifesaving and proved much more agile than 5 person surf boats that required a high degree of skill.   In time, lifesavers realized a double surf ski could do most everything a life boat could.  These early surf skis were very wide and bare little resemblance to those in use today. With little reverence for its past, the surf ski was transformed into a high speed, ocean going paddle craft for recreational and racing purposes.  The length grew to increase the waterline for speed and provide more stability when smashing through the waves.  To reduce drag, hulls were narrowed and the "swede" hull design which places the point of maximum beam behind the cockpit was implemented.  With the point of maximum beam behind the cockpit, water inertia and friction on the hull is reduced as water is moved out of the way more slowly over a longer wedge.  The swede hull also places the paddler closer to the water for a better vertical stroke by locating the cockpit in a more narrow part of the hull.  The iconic pointed ends and most of the rocker that allowed Greenland kayaks to keep their bows above the waves in rough seas are sacrificed in favor of a much longer waterline for speed.  To replace the missing rocker and the up-swept ends, the bow was made much more buoyant by squaring it off and making it taller.  These efficiencies, the lack of rocker and extended hull length, allows surfskis to put their full length on the water and achieve a greater bow angle and more effectively harness the gravity off the face of a wave to add significant speed to the overall average.  Wave riding skills are an intricate part of surfski discipline.  Surf skis have no edging control, so secondary stability and chines in the hull that produce a distinct secondary stability are not required by surfski technique.  Instead, a smooth rounded hull is used to reduce the wetted surface, thereby further reducing water friction.  But this requires more technique and a strict discipline to keep them upright.  Stability is attained through bracing and proper posture centered over the keel.  Typically, the paddler will lean forward to utilize the strongest torso muscles with knees close together, head pointed forward, chin up.  A rudder provides all directional movement and must be available at all times.  Surfski designs increased rudder availability by relocating the rudder forward of the stern to keep it in the water on steep waves that often lift the stern.  Unlike kayaks, surf skis have not attained a payload capacity and serve a short duration paddling purpose.  Surfskis are very different from a kayaks and demand a different skill set and paddling style.  Surf ski Discipline, and technique has evolved into two primary goals: keeping upright, and maximizing forward thrust.  Sprint kayaks share a similar technique with surfskis on flat water.  A proper stroke is crucial: Blade entry, catch, and follow through.  Also important, is a technique to maximize the efficient transfer of energy to the hull.  Surfskis are paddled with a wing paddle.  Forward lean with strong torso rotation is needed to utilize the core muscles for a sustained strong drive.  Good technique will propagate the rotation to the seat and transmit the energy through the legs which pump up and down to deliver energy to the hull through the foot pegs. Surfskis are not rolled, but are easily remounted from deep water.

As the relentless persistence of science sculpted the kayak,  new designs took shape along the same path of technological optimization as the surfski.  However, the purpose of the kayak is very different.  Not primarily designed for speed, the kayak was created for much more practical purposes and survival, including transportation, hunting, and fishing in rough waters, requiring maneuverability, stealth, and high degree of seaworthiness.  The Inuits solution: a highly rockered, upward pointed hull ends kept the kayak from diving into large waves, but reduced the waterline of the craft which was not that important.  The pronounced "V" shape of its hull and chines had little primary stability, but added a reliable secondary stability. The pronounced rockered "V" shaped hull also helped these kayaks track straight, and turn easy with edging.  Greenland kayaks have no skeg or rudder.  However, the pronounced "V" adds wetted surface and water friction to the hull which is not a problem for the Inuit style kayak.   East Greenland kayaks were flatter with little rocker giving them more speed with a longer waterline, but were less suitable for rougher waters as the rockerless pointed bow did not have enough buoyancy to lift above the waves.  Greenland kayaks fit snug to the paddler allowing a more symbiotic relation between paddler and craft for easy, quicker edging control and rolling in the event of a capsize. However, they had little room for gear.  Unlike surfskis, kayaks do not require a highly disciplined posture and steep paddle angle.  A lower paddle angle allows a wide unobstructed view angle for hunting, fishing, and keeping other paddlers in sight.  Kayaks can be righted with a brace or a roll.  Historically, the Inuits had no method for reentering their kayaks, since being separated from one's kayak meant certain death in the ice cold waters.  Their very lives relied on their rolls and other righting skills.  Modern kayaking allows the wet exit as a last line safety measure, in turn several methods for kayak reentry were added.   British style kayaks brought the kayak to the masses, while attempting to retain the spirit and characteristics of the original Greenland design.  The symbiotic fit is exchanged for a high volume hull to accommodate a generous amount of gear and paddlers of all shapes and sizes.  Thigh braces restore some of the body extension fit of Greenland kayaks.  West coast kayaks from the western American coast similarly retain the pointed bow and rocker, but add a rudder to a flattened stern to reduce weather-cocking in the high winds of the western American waters.

The designs and techniques of kayaks and surfskis evolved separately and are very different.  As they differ in their purpose, their benefits are mutually exclusive to each other.  Paddlers are left at a fork in the road to decide what they want and what they are willing to live without.  Similarly, their circles of paddlers are divided along the same lines.  Slowly, kayak manufactures started dabbling with design aspects of both paddle craft, adopting bits and pieces at a time.  To make a truly hybrid design was a difficult task fought with several technical challenges.  Moreover, they each require different skill sets and disciplines.  Kayak manufacturers began to adopt a very limited number of surfski features, yielding limited gains since these features on a kayak could not be paddled in the manner for which they were originally designed.   At Epic Kayaks, the two founders,  both surf ski champions, over a period of years, ventured so far as to entirely do away with the kayak hull in favor of a swede style surf ski hull in their 18x and 16x models, resulting in kayaks that bare little to no resemblance to their traditional roots, and perform far different than kayaks of Greenland lineage.  They were not the first to try this, but they went further by designing every facit of the craft to give surfski and kayak paddlers what they need to paddle the kayak in the manner befitting both crafts.
To satisfy surfski paddlers a reliable rudder that stays submerged and engaged in heavy waves was needed.  While a bottom mounted rudder works quite well for both uses, it cannot be retracted and is therefore unsuitable for most kayak purposes.  The most difficult task for Epic was coming up with a rudder design that would satisfy surfski requirements and fold away to preserve a kayak experience.  Their solution led them down a path to a rudder design unlike any other.  The stern of the hull was severed and turned into the movable portion of the rudder, housing a retractable spring loaded surfski blade, which could be extended from the bottom, forward from the stern.  When not used, the blade retracted into the stern section which in turn, locked into the center position to become the ridged stern of the kayak.  Their solution raised eyebrows in the industry.  While not a perfect surfski rudder, it went a long way to satisfy requirements of a hybrid craft and solved a long standing rudder problem of surfskis and kayaks with a spring retractable blade that moves out of the way when hit by an obstacle, and returns to place when the obstacle was gone.  Obstacles cause standard kayak rudders to kick up and not reset.  Standard surfski rudders just break off unless a stern mounted surf rudder is used.

Epic also did away with the iconic pointed bow and stern of a kayak in favor of the swede surfski hull with an elongated water line and a large  buoyant bow to keep it from burying under the waves.  The large single continuous foot brace facilitates energy transfer through the legs, and elongated cockpit coaming to allow the paddler to easily paddle the kayak like a kayak or surfski/racing K1 with plenty of room to extend the knees through the opening of the coaming enabling the paddler to pump energy into the hull with the legs and rotate down to the seat.  Padded knee holds just under the coaming sides allow the paddler to quickly switch from a surf ski posture to brace for a roll in the event of a capsize.  For a more kayak feel, the seat could be slid forward to allow a smaller paddler's legs to go further under the deck to better contact the hull for bracing and rolling.   Epic designed the seat to retain the functionality and feel of both a kayak and surfski, with smooth bare contoured fiberglass, allowing the surfski paddler a smooth surface to rotate on the seat to engage the lower back muscles and drive energy through the large foot brace.   Like many greenland style kayaks and surfskis, the back is low with little back support.  There is a lumbar pad for the lower back that does an adequate job of support while allowing a good layback roll.   Paddle blade cut-outs on the forward deck were added so the surfski paddler can initiate the catch phase with a vertical stroke close to the hull.  For the kayaker, the craft performed like a kayak responding well to edging, and very easy to roll.  However, as the large coaming provides the surfski paddler with extra room, this further reduces the symbiotic relationship kayak paddlers have with their kayaks, leaving the kayak paddler to alter their bracing technique to grip the undersides of the large coaming with the knees.  The large coaming may also let the paddler come out of the seat during a roll if the paddler does not sufficiently brace their knees against the sides of the cockpit.  To compensate, Epic heavily padded the underside of the deck around the front and sides of the cockpit.  They also put the seat on an ajustable track.  With the lower wetted rounded hull design, the kayak does not hold its course as well with the rudder up, but the rudder is extremely effective in all conditions.  The surfski paddler has what is needed to assume a proper posture, paddle stroke, plus a  reliable forward mounted rudder.  The hull responds like a surfski hull in the sea as it is able to catch waves and not bounce from the bow in rough seas like a high rocker kayak.  The rounded swede hull will likely unsettle beginner and intermediate paddlers initially in rough conditions with its much lower primary stability.  However, when loaded for an expedition, the kayak is quite stable, and rides comfortably at the expense of much of its blazing speed when riding empty.  To capture a little more secondary stability, Epic flared out the gunwales above the waterline behind the cockpit at the widest point of the kayak where the secondary stability emanates.  If the kayak does capsize,  it rolls very easily.  Paddlers of all types will enjoy being placed closer to the water as surfski paddlers expect for their vertical stroke since the cockpit is at a narrower point in the hull.  The 18x is not a beginner kayak, but is one a paddler can grow into and not outgrow.

For expedition use, the kayak rides very stable in the water.  The elongated cockpit makes it very easy to exit and enter.  The newer latch style hatches hold tighter and keep the compartments dryer.  They are also very easy to open and secure shut.  The hinged day hatch is especially convenient which stays fastened and has only one latch.

In an industry with hundreds of kayaks of different shapes, sizes, and specializations, the introduction of a new quirky looking design hardly raises much notice.  However, in 2009, paddler Frya Hoffmeister circumnavigated the continent of Australia (8570 miles) in an Epic 18x sport, and shaved more than a month off the time of the only other previous successful attempt by Paul Caffyn.   The paddling community finally accepted the Epic 18x as a serious expedition kayak and began to debate the merits of fast expedition kayaks.  Epic later went full circle and introduced the V8 surfski which adds a surfski top to the "18x Sport" kayak hull.  While this new kayak could never be the perfect solution or satisfy all the intricate demands of both types of craft, it did integrate the spirit of both a kayak and a surfski in an interesting way.  Harnessing all the benefits of this design will place extra demands on the paddler to expand their skill set to encompass at least a subset of kayak and surski techniques.  For their efforts, the paddler can wield a full featured kayak with the speed and prowess of a surfski when empty that settles down to a stable serious expedition kayak when loaded.

These are exciting times to be a paddler with advances in water dynamics and the melding of kayak and surfski technologies.  Only the future will tell if the Epic design will stand as a milestone in the evolution of the kayak, or be seen as a first deep foray into the realm of a true hybrid craft.  Several kayaks have penetrated the market utilizing aspects of both technologies in their own creative ways.  With the success of the Epic 18x, we will certainly see manufacturers committed to produce more hybrid type craft to take paddlers farther and faster.  Along this journey, paddlers will find they too must evolve to meet the skill set demands of these new craft.  Farther down the road refinements will likely mainstream hybrid design kayaks and push kayakers farther away from a 4000 year old legacy and discipline into one created for the modern age.  Only the future will tell if the traditional kayak will fade into irrelevance and be relegated to the romantic fascination of a few.

Copyright 2012 Lyman A Copps