Plywood Kayak Designs
Cirrus (Cirrus Hybrid)
Cirrus LT (Cirrus LT Hybrid)
NEW - Cirrus SLT
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Plywood kayaks construction features
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Kayak Design specs...
The stuff that actually tells you something

Cirrus - 17.5' x 22" ( 5,33 x 0,558m)

The inspiration to build the ultimate hard chine, stitch and glue kayak was all too easy. To instill a plywood kayak with some of the nice characteristics of its wood strip cousins took some creative tweaking but the effort paid off and I just couldn't be happier with the cruiser that was born.
Fast and agile hull form was necessarily at the top of my list of "must have's", however, bending flat plywood to an efficient kayak proved quite a challenge. The solution came by starting with a fast round hull as a template and forming the plywood plates with multiple stations to impart an optimal shape to the hull. As a result, the area/displacement ratio (efficiency factor) of the Cirrus indeed puts some of the well known wood strip designs to shame. This kayak IS fast and holds its course straight like an arrow !
The hard chine on the Cirrus begins and ends well above the waterline, giving it the curvature to turn the kayak 'on a dime' in a carved turn.
For its size and displacement, the stitch and glue Cirrus is feather light at 35lb and it features the largest 'hull flare' of all One Ocean Kayak designs. Being paddled by a 'top heavy' guy like myself, the stability envelope is more than comfortable and the secondary stability especially, feels fantastic.
A major thrust of the design was to build the deck in such a way as to increase the 'knee room' in the cockpit and enlarge the gear storage space at the same time. The pleasing aesthetic effect of the round, wood strip-like deck with smooth coaming and flush hatches came as a result. If you would prefer to paddle the Cirrus with a nicely contoured real wood strip deck, you can have that option with the Cirrus Hybrid.
Riding the well behaved Cirrus is a pure blast and if you are in the 150 - 250lb range, this may just be the fastest and most comfortable plywood kayak you will have ever paddled!

 
Snuck out and put the Cirrus in the water this morning. Very impressive. Stable, quick and responsive. Only needs a bit of tweaking on the seat and ready to go. Then I will see if my camping gear fits and if it does I will use it for trips and sell my CLC boats.
Comments: straight forward construction. Although the strong back is a bit more time consuming it is worthwhile in a truer hull. Good design, good instructions. Thanks. Overall, I enjoyed the new experience of laminating the hatch seats and coaming especially.
See you on the water. - Dave Murray



Design Features
Plywood Building Plans
Kayak building Plans











Stitch & Glue Manual
Stitch-n-Glue Sea Kayak
  •  Hull form - The Cirrus has a single hard chine, Swede hull form. Generously curved chines respond quickly to leaned turns and aid in excellent handling performance and responsiveness.

  •  A pronounced rocker in the bow and a sharp V hull profile along the entire kayak give the Cirrus the superb directional stability. There is no hint of a self induced course deviation and the kayak follows a straight line even in low speed coasting. No need for a skeg or rudder. Your propulsion energy is efficiently channeled to speed rather than side to side yaw.

  •  Sharp bow and stern entrance and exit angle as well as its Length/Beam ratio of 9.75 (second best after the Expedition) cut down significantly on wave resistance. The Cirrus Area / Displacement ratio of 8.66 simply puts it among the most efficient of plywood hulls and even some well known wood strip designs!

  • Unlike many plywood kayaks which expose the entire hard chine under water, the length of the 'hard edge' on the Cirrus is significantly shortened below the designed waterline which makes for a faster kayak due to 'cleaner' surface and delayed onset of turbulent flow along the fore hull.

  •  The narrow waterline beam (width) of 19.45" is flared out to 22 inches overall beam for reassuring reserve stability in lean and bracing maneuvers. The hull volume is also well distributed forming a full water plane area aiding greatly in overall stability. This combination will be especially appreciated by top heavy paddlers and novice kayakers will feel in their own element in no time.

  • Multi-plate, cambered deck with with spacious cockpit interior and flush hatches.

  • Optimal performance around 210lb (95,4kg) paddler and gear weight.
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Kayak Design specs...
The stuff that actually tells you something

Cirrus LT - 16' x 21.5" ( 4,87 x 0,546m)

This feather light kayak is the smaller "twin" of the Cirrus identical in every attribute of style, shape and performance, but its scale. Slightly narrowed in beam, reduced in cockpit depth and shortened by a whole foot and a half, it is designed primarily for the comfort and paddling needs of physically smaller and lighter paddlers. Speaking from my perspective of a 250 lb paddler, it means anyone between 130 to about 187 pounds. At the designed weight range of 32 to 35lb, this kayak is light enough to be loaded and carried by almost anyone, kids included. As light as it is to carry on land, it will also "peel out" of it's starting line with ease and at highest acceleration. The Cirrus LT can of course be be paddled in salt water as well as lakes and ponds. At 16 foot overall length it will turn around on a dime in any tight spot, your workshop and garage included!
In addition to its agility and nimble nature, it retains comfortable stability, ease of turning and impeccable straight tracking. So, if the Cirrus "speaks to you" but is too much of a kayak for your person, now you can have it in the Cirrus LT or the Cirrus LT Hybrid. The round Hybrid deck has slightly higher volume than the flat faceted deck of the all plywood kayak.
 
Thank you for the great design. It has a very sexy streamlined look, and paddles well. Very good tracking and stability. I am especially pleased by it's performance in crosswinds, rear-quarter and following seas - John Caldeira (Texas)
Video clip of John doing Eskimo roll with the Cirrus LT
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Thanks for all your help in the construction of my Cirrus LT. I took it out for sea trials yesterday and it performed flawlessly. It feels incredibly strong, tracks beautifully, responds well to a lean, and rolls like a log. I'm taking into the pool tonight to teach a rolling course. Thanks again - your plans are excellent and your support is unparallelled. The new Cirrus LT is a boat I'm truly proud of. - Alan Stanley


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Kayak Design specs...
The stuff that actually tells you something

Cirrus SLT - 14.4' x 20.9" ( 4,41 x 0,532m)

This is a kid's first dream kayak with serious grown up performance that they will not so easily outgrow. At mere 28lb it is just about the lightest kayak of it's type available, even ligter than genuine racing kayaks. It was designed with great care to inherit all the nice tracking, efficiency and stability behavior from its parent design the Cirrus. The Cirrus SLT could also be the ideal craft in which to introduce your youngster to the joys of paddling in nature and perhaps even some practical woodworking skills in your shop; definitely a memorable building experience for both kids and the "adults". The size of the kayak makes building possible in the smallest of shops and garages. Even shop teachers and Scouts now have a kayak that is basically dedicated for paddlers from 88 to 145lb and under 5'6"in height. (Needless to say, it is vital to provide the best care, supevision and on the water training to enjoy kayaking safely.)
Even though the the Cirrus SLT is sized for younger paddlers, it is by no means intended only for them. This kayak is a blast to paddle for anyone of any age so long that the paddler size and weight match the recommended paddlers sizing in the technical specs.
The Cirrus SLT allows construction of either the standard cockpit or a fully recessed one with integral knee braces.

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One Ocean Kayaks Plywood Construction Features
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  • Lightweight monocoque construction with 100% continuous internal and external fiberglass skins. - Complete fiberglass coverage assures the ultimate strength and long term protection of your plywood kayak inside and out. Both the deck and hull work in concert as a strong structure. Many S&G kayaks are built without fiberglass cover on the inside deck which makes a weaker kayak, causing eventual moisture absorption through cracked epoxy coat = gradual weight gain. Fiberglassed bulkheads that hold the kayak plates together also prevent application of one continuous fiberglass skin on the inside hull = more work, weight and less than optimal strength.

  • Builder's choice of plywood types and thickness (1/8" [3mm] up to 1/4" [6.2mm]) to accommodate local availability, cost, weight and multiple choice of decorative veneer plywood for deck and even hull. - Why not build your deck with walnut, tiger maple or cherry veneer plywood?! One Ocean S&G design permits any mix and match of plywood since kayak construction and accuracy is independent of plywood thickness. With 'cookie cutter' kayak kits and plans you get to choose between marine plywood and marine plywood.

  • Fixed cradle and multi-station setup guarantees kayak accuracy and exact hull shape optimized for ultimate hydrodynamic performance. - One Ocean S&G is built on a precise and fixed foundation. You will not be fighting with twisting plates - pieces are wired individually into the kayak with great accuracy without the need for straps or tie-downs. The hull is also formed with multiple stations (forms) to give your kayak truly hydrodynamically efficient shape and ergonomically molded deck - 4 stations common with other kits is plainly not enough to impart efficient hull shape, however, it greatly saves on shipping and manufacturing cost with no benefit to your kayak performance, gear storage or cockpit space.

  • NO need for internal ribs, stiffeners, rub rails, sheer clamps, drill jigs and permanent forms other than bulkheads.- Why build a kayak that incorporates lots of redundant features to hold the plywood together while adding more complexity, internal 'snags' and weight. One Ocean Kayaks S&G design is uncluttered and streamlined. The internal kayak volume is spacious and completely clean with only two bulkheads.

  • NO imbedded metal wires and/or fasteners or heavy epoxy 'end-pours'.- One Ocean Kayaks building method requires no 'heating' to pull wire out of epoxy nor does it leave a single copper nail or wire imbedded in the kayak. Filleting is done cleanly without wires present and no pouring of pounds of epoxy into the tips is necessary.

  • Non-fixed position bulkheads to adjust for larger cockpit space, more leg room or larger gear storage.- One Ocean Stitch & Glue design doesn't require bulkheads to hold the kayak shape. Bulkheads are installed last and are never fiberglassed in so you can decide to move them if you need more gear or foot space, for example. (consider the location of hatches beforehand).

  • Flush-to-deck and airtight hatch design. Position hatches as you like or alter the shape/ size to suite your needs.- Why put up with unnecessary sea spray on your face?! One Ocean Kayaks hatch lids come from the deck and maintain the same shape as the deck resulting in a clean and flush hatches. There are no clutsy, deck-spray inducing 'built-ons'.

  • Multiple cockpit sizes in the plans or just reshape one to your requirements.- There is no fun in crawling through cockpits designed for someone half your size! One Ocean S&G kayak design doesn't come with one 'fit for all' cockpit opening but a choice of many. Plans contain multiple sizes which can be further modified for your body and paddling needs. I also custom alter the shape or size of the templates per your specifications and request at no cost!
- See also -
S&G Manual | S&G plans | Cirrus photo gallery | Cirrus technical specs

Building Plywood Kayak
and
Wood Strip Kayak Designs


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Last page update: 29 October 2013

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