Spindrift – Jon Myers

First, a wood strip kayak is a very manageable project and would be a walk in the park with your experience ;-)

Of the kayaks you mention, Spindrift would be close to the Vajda in stability – less beam is compensated by length and more rocker (lowers the CG). But since you don't mention the most important criteria for choosing a kayak (how and where you intend to use it) – it is difficult to say anything relevant about them. But in short, Frej, Spray, and Panthera are more stable than the Vajda, in initial stability and even more in secondary. None of them are as fast as Vajda on flatwater, all of them faster in wind and waves. For touring in different conditions on open sea you might want to include Njord in your list (fast, efficient, and with easy movements in).

Otherwise, the main difference is that Frej and Njord are skeg kayaks (highly maneuverable, using an adjustable skeg to fine-tune tracking), while Panthera, Spray, and Spindrift are rudder-dependant surfskis/sea kayaks (using an efficient rudder system to control both turning and tracking – which give them an edge surfing big waves). None of them is of the old traditional sea kayak type (hard tracking and needing a rudder to turn).

Hi Matthias,

Yes, the materials are usually available locally. Strips (fir, spruce, cedar, paulownia, etc) can be square cut or bead-and-cove as per the building manual. Station molds and stems are available as dwg files if wished – may save a little time, cost a little more, and does not affect the final finish of the kayak (depends primarily on what happens later in the process ;-). Stations are cut in particleboard, plywood, MDF, or similar, while stems often are solid wood.

The kayaks are designed for paddlers slightly heavier than you, so it may be a good idea to shorten them slightly (as advised on the plans), to not float unnecessarily high on the water. But it is not a big problem – your Vajda is designed for the same weight as my kayaks are ;-)

Hi Mattias

I would say that Squall 580 and Spindrift are reasonably alike in stability, speed, maneuverability etc. The hulls are similar in configuration (I was involved in the first stages of the Squall development), and the dimensional differences may work both ways. Spindrift is longer which means a higher top speed and slightly more initial stability, the less beam also adds some speed potential but robs the stability advantage of the LOA, and a couple of kg:s extra lessens the speed advantage while increasing the stability (even with Paulownia it is hard, if not impossible, to match the professional construction methods of NK). All in all, I’d say that they would feel a bit differently but perform quite similarly.

The advantage of Paulownia is, of course, the low density, the disadvantage is considerably less compression and tensile strength (the most important numbers for kayak building). The numbers indicate typically approx half of the comparable numbers for spruce, slightly lower also than black poplar, while double that of balsa. It might result in a weight reduction of about 2,5-3 kg on a Spindrift. But note that both species vary wildly depending on soil, temp zone, where in the trunk the planks are taken etc.

Now, the wood is a core material and part of the structural properties in the hull comes from the epoxy/fiberglass layers – which suggests that it wouldn’t be a good idea to also reduce the weight of the cloth (which anyway wouldn’t contribute to more than a couple of hg:s in weight reduction).

The cockpit can be made in several ways. The drawings have lines for a generic cockpit that may serve as is, or as a starting point for a customization. One way is to fill the cockpit area in the (taped together) hull/deck with a foam material (a number of ground isolation panels) and carve out the cockpit to suit, then laminate the final cockpit in that mold, discard the foam and glue the cockpit into the finished hull.

Another way is measurements taken from a comfortable and functional commercial cockpit to use as a starting point.

Some builders have made a full mold of a commercial cockpit and laminated their own on this mold (place the surfski on a level and stable support), cover the cockpit with plastic, laminate a few layers of fiberglass/epoxy over it, put a big waterfilled plastic bag in to force the laminate in contact with the seat, when cured stabilize the mold with some glued in wooden sticks and lift it out).

Björn

There is no reason to add extra cloth (glass or carbon) when using paulownia. The fabric has 3-4 times the density of the wood, so the advantage of using lighter wood is lost, leaving just a few shortcomings.

Paulownia is not as tough as spruce/fir when it comes to hard (ab-)use, but neither are the light delicate elite surfskis, used in challenging ocean races.

Use paulownia and be reasonably careful, or use fir if you want an almost indestructible craft.

You might shorten a Spindrift slightly to keep the hull on the design waterline. Floating too high, it becomes harder to control in strong wind.

As a relevant adjustment, I suggest changing the distance between molds from 38 cm to 36 cm. It cuts approx 10 kg displacement without lowering the speed potential too much. Info for this is given on the plans.

A surfski with an open cockpit generally has the design waterline slightly lower on the hull (and thus lower displacement), to help keep the deck and cockpit free from water.