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Frej SG

$750.00

The renown strip “Frej” designed by Björn Thomasson is now available in stitch & glue construction for home builders.   The original Frej is one of Björn Thomasson’s most successful strip designs even being adapted to commercial production. It’s roughly based on his Njord but is shorter and more maneuverable for surfing, playing in waves and touring in rough conditions.

In the Fall of 2015, after my successful design work adapting the Black Pearls and Alleqs to true stitch & glue, Björn and I discussed a S&G Frej project. This is the result. With the multi-chine hull and rounded deck it’s a very close approximation to the strip design but much easier to build. The kit will include plywood recesses for Kajak-Sport hatches that you can make and add to the deck.

More information on the strip “Frej” can be found here:
http://www.thomassondesign.com/en/catalog/my-kayaks/frej

There are two sizes of cockpits to choose.  Most paddlers will prefer the stock ocean cockpit.  It is 40 x 60 cm (15.75″ x 23.5″) and is more in-line with the Frej’s roots.  For those that need a bigger opening, there is an optional “keyhole” version with integral wings.  The keyhole is 40 x 80 cm (15.75″ x 31.5″).

The kit includes plywood parts to construct recesses for Kajak-Sport 43/30 oval and 24 round hatches (available separately).

It is as a pre-cut plywood kit for home builders.  It can also be custom built by CSCWC.

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Description

The renown strip “Frej” designed by Björn Thomasson is now available in stitch & glue construction for home builders.   The original Frej is one of Björn Thomasson’s most successful strip designs even being adapted to commercial production. It’s roughly based on his Njord but is shorter and more maneuverable for surfing, playing in waves and touring in rough conditions.

In the Fall of 2015, after my successful design work adapting the Black Pearls and Alleqs to true stitch & glue, Björn and I discussed a S&G Frej project. This is the result. With the multi-chine hull and rounded deck it’s a very close approximation to the strip design but much easier to build. The kit will include plywood recesses for Kajak-Sport hatches that you can make and add to the deck.

There are two sizes of cockpits to choose.  Most paddlers will prefer the stock ocean cockpit.  It is 40 x 60 cm (15.75″ x 23.5″) and is more in-line with the Frej’s roots.  For those that need a bigger opening, there is an optional “keyhole” version with integral wings.  The keyhole is 40 x 80 cm (15.75″ x 31.5″).

It is as a pre-cut plywood kit for home builders.  It can also be custom built by CSCWC.

logoIn coordination with Björn Thomasson and Petruskajak of Sweden, we have  used our advanced naval architecture and CAD programs have adapted it to true stitch & glue construction using 3mm and 4mm okoume marine plywood.

The kit includes hull and deck panels that are professionally cut and shipped by Chesapeake Light Craft from 3mm and 4mm BS 1088 okoume marine plywood, and the forms from particleboard or MDF.

The kit feature full bulkheads and a stacked plywood coaming for easy construction.

The kit includes plywood parts to construct recesses for Kajak-Sport 43/30 oval and 24 round hatches (available separately).

The kit includes only the plywood components; solid wood (for the sheer clamp), epoxy, fiberglass, hardware, foot braces, and so on are not included.  It is packed in CLC’s standard kayak shipping carton.

Below is an except from Björn’s website for the strip Frej:

A couple of years ago I began sketching for a new sea kayak, based on the Njord, but shorter and more maneuverable for surfing, playing in waves and touring in rough conditions. For different reasons, I quit halfway – primarily because I was so satisfied with my Njord, and more so for every year. I found the maneuverability so excellent that I did not see the need for improving this at the expense of speed.

Furthermore, I designed the Discovery for Seabird Designs. Though shorter and wider than my initial sketch, it was received with (to me and my love for narrow and fast craft) surprising enthusiasm*, and one reviewer recommends the kayak for the very same purposes I had in mind.

So I pulled the sketches from the forgotten-ideas-folder and started playing with the hydrodynamics. Most was already done: starting from the Njord hull I had reduced the length from 559 to 507 cm, increased the beam from 51 to 54 cm, increased the keel rocker and lifted the stems slightly (a shorter kayak risks dipping the stems in steep seas more than a longer). So far so good. I aimed for approximately the same displacement as Njord – 130 kg – but ended up a few kg over that, when I was satisfied with the other hull data.

Key features are:

  • Easily handled – minimal resistance in touring pace and turning almost like a white water kayak,
  • Safe and snug –smooth and easily countered movements mean that you sit dry and relaxed even in rough sea conditions,
  • Adaptable – Frej does whatever you want it to do, whether it is touring with a full load, play and surf in waves, rock-hopping or a rolling competition…

Hydrostatics

Design Frej SG
Designer Björn Thomasson
Class (Sound Rowers) Fast Sea Kayak
Length 16.76 ft 510.8 cm
Beam 21.26 in 54.0 cm
Waterline Length (LWL) 16.05 ft 489.3 cm
Waterline Beam (BWL) 20.04 in 50.9 cm
Design Displacement 250.0 lb 113.0 kg
Draft 4.41 in 11.2 cm
Wetted Surface Area 20.52 sf 1.91 sq m
Surface Area, Total 49.45 sf 4.59 sq m
Approx Boat Weight 33.00 lb 15.0 kg
Displaced Volume 3.99 cf 113.0 Liters
LCB (Longitudinal Center of Buoyancy) 8.10 ft 246.9 cm
LCB (Longitudinal Center of Buoyancy) 0.48 % 0.48 %
VCB (Vertical Center of Buoyancy) 0.23 ft 7.10 cm
LWL / BWL 9.61 9.61
Cb (Block) 0.370 0.370
Cm (midship Coeff) 0.751 0.751
Cp (Prismatic) 0.492 0.492
Trans. Metacentric Height 0.91 ft 27.8 cm
Resistance at 3 Knots 1.82 lbf 8.16 N
Resistance at 5 Knots 6.63 lbf 29.72 N

Design Statement

From Björn’s website:

As told above, Frej is developed (not very far) from Njord – a slightly shorter, slightly wider, a little more rockered Njord. The background, therefore, is essentially the same.

The name Frej felt relevant: Frej was, in the Norse mythology the son of Njord, the Vanir God of the sea, the weather, the fishermen and the merchants of the sea.

There are some qualities I could improve on, not the least with knowledge acquired designing the Sea Racer and Nordic Kayaks Fusion – new insights in the complex balance between speed-stability, volume coefficient and such. With a bit of tweaking, I could lower the friction and wave-building resistance further, without losing stability. Some procrastination is not always a bad thing 😉

Ny kajak: MotståndskurvaThe increased rocker places the paddler deeper in then water and lowers the Cp considerably, and to compensate I worked a little more volume out in the stems. Thus, Cp decreased no more than from 0,56 to 0,52. This means that the efficient speed range is lower than Njords, which might be appreciated by most of the potential builders: Frej (blue curve) has less resistance in speeds below approx 8 km/t (4,3 knots), while Njord (purple curve) wins at higher speeds. The extra volume also helps keep the stems from diving in steep seas.

Frej turns quicker than Njord – the rocker, sharp midship chines, and the rather flat bottom combine to give quick and precise maneuvering for surf and play. To balance the maneuverability the stern is shaped to give a directional stability proportional to the speed – but for long distance touring it still needs an adjustable skeg. I have no doubt whatsoever that Frej will be a highly competent partner to paddlers who like big water play, surfing and tough touring in whatever conditions that might be encountered.

Interesting is that I succeeded in minimizing the wetted surface in relation to the displacement (and thereby the friction) to a very low figure, in spite of the sharp chines. Relative the mathematical minimum for a 135 kg displacement, the underwater area is at no station position more than 6,6 % over – promising a quite fast and easily driven hull in its class.

Safety is handled as in Njord. Rolling, support braces, balance brace etc is cheatingly simple: a little more stability to overcome during rotation, but better secondary stability helps in the final stage – and, of course, the low sheer midships and aft deck is inherited from Njord, facilitating stroke dynamics in paddling, rolling and maneuvering. Better overall stability means that it is easier to climb back into the cockpit after a wet exit, for non-rollers.

Stitch & Glue Kit: Plywood Components

This is a basic CNC-cut kit.  The hull panels, deck panels and coaming parts are professionally cut by Chesapeake Light Craft from 3mm or 4mm BS 1088 okoume marine plywood, depending on the design.  The forms are cut from particleboard or MDF.  This kit includes only the plywood components. Any solid wood for the sheer clamp, masik and other deck beams, epoxy, fiberglass, hardware, footbraces, and so on are not included.  We encourage you to purchase those from local sources.

The kit is packed in CLC’s standard kayak shipping carton.  It’s pretty light so shipping is inexpensive.  We’ll contact you with a shipping quote once you’ve placed your order, and you’ll approve the shipping before you’re charged for the kit.

Additional information

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