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On Njord

Hey Björn, Maiden Voyage successful!
In a few words: amazing!!! light, fast, stable! due to the high bow, it has some weathercocking tendency, but as you start moving, the rudder kicks in and keeps it going like a train on its rails.
Super happy!
Best regards,
Chris Buttel


Images | Particulars | More about | Background and history


Plans, Panthera - 108 EUR Purchase


Panthera is a new surfski sea-kayak hybrid – simply put a surfski with a kayak deck. But that would be an over-simplification. Even if the hull is a Spindrift there is also a noticeable influence from Njord. I expect the performance to be a tad less extreme than that of a thoroughbred surfski, but yet manageable should the paddler develop an acute desire to surf diagonally in high speed on large waves. I also expect competent paddlers to be able to keep Panthera at speeds well above hull speed á la surfskis off following seas.

Basically, Panthera is so close to a genuine surfski that a rudder is needed to meet the potential (more about the difference here). An under-the-hull rudder with a surfski type of pedals is, of course, the best, but for fast touring, a rudder on the stern will do fine – preferably with one of the larger blades. With a full touring load, the kayak settles down to more directional stability for relaxed long distance paddling.

John Abercrombie, who built the first Panthera (see below) published this review after a short trial when mid-winter Canada offered a few days with open water.

I thought I'd share my first paddling impressions of my new boat (Bjorn Thomasson Panthera) from a very short outing this afternoon.
I like it! ;-)
Hopping in the boat, the initial feel is a lot like Frej - it feels compact and 'ready to go' but not at all 'twitchy' or unstable.
Secondary stability is excellent- I can set it up on edge very easily, and it stays there. It rolls easily - and I'm not an accomplished roller, at all. The low back deck (like Frej) makes sweep rolls easy.
It feels quick - with the footboard, it's easy to put my knees and feet in the middle of the boat and get good rotation and drive. I'll need to put the GPS on it for a longer outing to get some data on the speed.
With the rudder down, it goes where it's told with no fuss.
Rudder up - it's quite agile even when not edged (flat). Responds well to sweep strokes which skid the stern around easily, and bow rudder strokes work well. When set on edge, the steering strokes work even better (as you'd expect). Hanging draw stroke works well.
I'll let you know how it does in a breeze and waves, and also with some more weight in the boat, as the season progresses.

John Abercrombie

Arto Nikula has published a photo blog with a lot of instructive Panthera construction photos.

Peter Träisk build an interesting integral rudder on his Panthera (text in Swedish).

Panthera L

I got a request from a tall and heavy paddler about a roomier Panthera, so I added a little deck height (2.5 cm) and beam (1 cm) on the same LOA and named the result Panthera L. It loads 15 kg more on the design waterline and has 20 liters more internal volume. Are you a big guy (>190 cm/95 kg), don't believe in traveling light or has other good reasons you may want to add Panthera "L" in the comment field when ordering.

Panthera and Panthera L
Compare the outer dimensions of Panthera and Panthera L

Panthera stitch-and-glue

Om du tvekar inför ett stripbygge, finns det ett enklare sätt att få nästan samma kajak. Jag har tillsammans med Petruskajak i Tranås ritat/utvecklat en plywoodversion av Panthera. Dessa finns  att bygga hos Petruskajak i hans numera välkända 8-dagarskurser, men kan också köpas som byggsats.

Stitch-and-glue-konceptet innebär att färdiga CNC-frästa plywoodpaneler "sys" ihop till skrov och däck, varefter skarvarna stabiliseras på insidan med glasfiberremsor i epoxy, och utsidan lamineras med glasfiber. Resultatet blir en lätt och stark kajak på grovt räknat halva tiden mot ett stripbygge – eller på en fjärdedel av tiden för den som har ambitioner som inbegriper dekorativ strippning med olika träslag ;-)

S&G Panthera är en lättbyggd version Panthera. Metoden kräver enkelkrökta paneler, vilket innebär plana ytor och skarpa slag. Det betyder i praktiken en aning fartförlust genom turbulens och en aning mindre innervolym. Skillnader i egenskaper är i praktiken knappt märkbara, och får vägas mot det enklare bygget. Prototypbygget väger 16,5 kg med Kajaksportluckor och Smarttrackroder.

S&G Panthera S&G Panthera


John Abercrombie – PantheraJohn Abercrombie – PantheraPantheraPanthera – Arto NikulaFrej and Panthera – Arto NikulaPanthera – Arto NikulaPanthera – Arto NikulaPanthera – Arto NikulaPanthera – Arto NikulaPanthera – Dan CaouettePanthera – Dan CaouettePanthera – Juho PaasoPanthera – Juho PaasoPanthera – Juho PaasoPanthera – Jan LindblomPanthera – Fredrik Pantze Panthera – Fredrik Pantze Panthera – Fredrik Pantze Panthera – Fredrik Pantze Panthera – Fredrik Pantze Panthera – Jacob Norris, Malmö Kanotklubbs 24-timmars kayak-challenge 2019Panthera – Jacob Norris, Malmö Kanotklubbs 24-timmars kayak-challenge 2019Panthera – Christian ButtelPanthera – Christian ButtelPanthera – Christian ButtelPanthera – Jan NorlinPanthera –– Jan NorlinPanthera –– Jan NorlinPanthera – Bas TinhoutPanthera – Bas TinhoutPanthera – Bas TinhoutPanthera – John AbercrombiePanthera – John AbercrombiePanthera – John AbercrombiePanthera – John AbercrombiePanthera – John AbercrombiePanthera – Chris ButtelPanthera – Lars JörbladPanthera – Lars JörbladPanthera – Lars JörbladNanoq – Jorma Kiretti


Panthera, lines

Length¹ 560/552 cm (overall/WL)
Beam 52/49 cm (overall/WL)
Draft 10 cm
Cockpit¹ 78x39 cm
Height¹ 28.5/18 cm (in front of/behind the cockpit)
Weight² 16-19 kg
Displacement/volume⁶ 120 kg/375 litre
Prismatic coefficient 0.563
Wetted surface 2.07 m²
Stability⁵ 3/4 (initial/secondary stability)
Intended use Fast touring, surfing, sea kayak racing
Length¹ 560/552 cm (overall/WL)
Beam 53/50 cm (overall/WL)
Draft 11 cm
Cockpit¹ 80x40 cm
Height¹ 31/20 cm (in front of/behind the cockpit)
Weight² 17-20 kg
Displacement/volume⁶ 135 kg/395 litre
Prismatic coefficient 0.563
Wetted surface 2.12 m²
Stability⁵ 3/4 (initial/secondary stability)
Intended use Fast touring, surfing, sea kayak racing

¹ These dimensions can be adapted to suit personal needs or wishes.
² Depending on type of wood, equipment, care with epoxy usage, sanding etc. etc.
³ The speed numbers are based on mathematical standard formulas (175 lb paddler + 30 lb carco weight) and corrected from the kayaks actual performance om trials, on tours and in races.
⁴ Calculated resistance in 4 and 5 knots (at nominal load capacity).
⁵ Initial stability and secondary stability on a subjective scale, where 1 is very tippy and 5 is very stable.
⁶ Displacement is kayak + paddler + load. Count off the kayak weight to get the load capacity.


The plan sheets contain the information needed to build the kayak/canoe. Station molds, stems and construction details are full scale. For kayaks the recommended cockpit size is shown half scale with offsets for a full scale drawing and advice on altering the size. On the plans you will also find advice on how to shorten or lengthen the craft. Lines and construction drawings are in metric scale 1:10.

Panthera plans

The illustrated step-by-step building manual is in Swedish only, but it is available online in English: it covers all steps in detail and will guide first-time builders through the project.

Plans, Panthera - 108 EUR Purchase

Minimum window dimensions to get your kayak out from the workshop:

Background and history

On the far side of the Atlantic, there has been for some time a certain interest in surfskis with kayak deck. Dan Caouette got an order for a Spray with deck and built this beauty.

Dan Caouettes Spray med kajaksittbrunn

John Abercrombie and I have exchanged ideas and details for a similar project via mail for a while. It got me looking in my inspiration folder where I hide those more or less whimsical ideas that occasionally might end up in a project: this time a surfski-kayak with lines inspired from the beautiful and exciting Jaguar CX75, an electric hybrid concept supercar, built to celebrate the Jaguar 75th anniversary.

While being a very exciting car – electric motors on all four wheels (4WD without differential and complicated power distribution circuitry) at 778 HP total power, two micro gas turbines from Bladon Jets charging the batteries to achieve 900 km range, and that can use almost any fuel (diesel, biofuel, natural compressed gas, ordinary petrol) emitting 28gr CO2/km over the entire distance – it is also one of the most well-designed cars I have seen for a long time. While many supercars seem to be the accumulation of individually attractive lines and areas that don't quite add up, sometimes backed up by wow-gadgets, the Jag feels like a successful unified design job, looking good from every viewing angle, exuding power, function and elegance. Unfortunately, the global economic crisis erased much of the market for ridiculously expensive supercars, and the project was discontinued in 2012.

There were a lot of photos and drawings in my idea folder, and I started playing with some of them on the digital drawing board.


The starting points what was to become Panthera in 2015 were: surfski-like performance (superb maneuverability, tamed with an efficient rudder), stability on par with Frej (John referred to a Frej he built some time ago), interior volume as Njord, deck height to accommodate the pedal system of choice, a dip in the sheer line to allow for deep cutouts to improve the stroke geometry – and of course: as much beauty and interest as I can design into the lines ;-)

Panthera and Jaguar

Visually the Jag has been inspiration, but a kayak is a much simpler shape than a car, lacking most of the details that spice up a well-designed car: windows, lights, wheelhouses, air intake, exhaust etc, so in the end, it was not much more than a sweeping sheer line that I could transfer to the kayak. More can be achieved by painting schemes and decals – but for me and for now, it is an interesting appearance on an efficient hull I focussed on. Superficial styling will be left to the builders. For now...

The result is a yet unnamed kayak and plans shipped across the Atlantic to John, who finished the prototype – a real beauty in a black hull and copper-colored deck (inspired from Dan Caouette's 5-part Black Pearl). The project has been discussed and commented on the Kayak Building Forum.


John Abercrombies 'noname' under en kort paus i ösregn och storm som just nu dominerar BC

The name Panthera is the Latin name for Jaguar: Panthera Onca.

A Panthera under construction in Luxembourg:

Panthera under construction in Luxembourg

If someone wants to go berserk with the painting scheme, here is an old idea that was abandoned some years ago when Point 6.5 beat me to the name Orca for a surfski. A sea predator would, of course, be a more appropriate inspiration for a kayak than a land predator – but don't blame me if a real Orca takes a fancy to the little pretty kayak-orca…

A marine version of the jag ;-)

Dan Caouette built an Orca-styled baidarka recently. Very nice!

Panthera Special

Two special Pantheras were designed for long-distance competitions and extreme paddling, both dimensionally adjusted for their owners and built by Petruskajak in Tranås:

For the 2018 season a Panthera for Fylkir Saevarson, with Icelandic flag decor...

Panthera – Fylkir Saevarson

...and for 2019 a Panthera for Jacob Norris, in English racing green (the photo is from M24KC, Malmö Kanotklubb's 24-hour kayak challenge)

Panthera – Jacob Norris, Malmö Kanotklubbs 24-timmars kayak-challenge 2019
"Den nye Panthera er blevet min bedste kompis, det er muligvis Danmarks hurtigste havkajak. (The new Panthera has become my best friend, possibly Denmark's fastest sea kayak)"


Great to see the Panthera on the website. Is the price really 950 EUR?!

Oh no, of course not. I am still working on translations, adding numbers and the never-ending task of proofreading ;-)

Ah! New price makes much more sense. Feel free to delete my comments.

No need for that. I believe in keeping all comments (but spam) as part of the work process, and I don't mind sharing even my silly mistakes ;-)

Besides, I am grateful for the help...

(I should perhaps add that I have deleted a couple of comments over the years at the request of the commenteer.)

Always loved that orca... :)

Thanks Dan. I was sorry we couldn't orca-paint one of the first surfskis for the trade shows – somewhat impractical but it would have been fun.

Hi Bjorn,

You need to correct the price on the Nanoq plans too.


Thanks Etienne, another translation error ;-)

Hej Björn!

Jag är riktigt sugen på att bygga mig en ny kajak. Idag paddlar jag mestadels surfski, en Seabird Wave 6.1 men har även en Smart för myspaddlingen. Dock är jag sugen på en snabbare kajak utan att behöva gå på det "extrema" som Havsracer. Jag är väl att klassa som nybörjare då jag började paddla förra sommaren och då med surfskin som första kajak (har ännu inte kantrat med den ;-)

Det jag undrar lite över är hur du skulle beskriva stabiliteten i exempelvis Panthera eller Hunter mot för Wave 6.1?

Hunter och Panthera har snarlika stabilitetkurvor (eller snarare potential – eftersom stabiliteten beror mer på tyngdpunktens läge än på skrovformen). Wave har aningen mindre initialstabilitet med ungefär samma slutstyvhet, beroende dels på den mindre totalbredden och dels på att den smalare botten tvingar upp sitsen en aning jämfört med de andra båda.

Panthera bär sig åt ungefär som Wave i sjön, medan Hunter är en grönlandskajak som kontrolleras bättre med skädda än med roder. Titta även på Njord som är min favorit i skädda-gruppen, både för lek och långfärd.

Hi Bjorn

I have been researching wood surfskis that I could build and love your designs.

I have been reluctant to commit on a boat build, partly because the open cockpit surfski would shorten my season here in Michigan. Cold weather paddles while being entirely exposed to the elements gets a bit dicey for me. The solution would be the Panthera, if it is available with a cockpit opening large enough that I could paddle using a surfski technique Knees high and driving with my legs but small enough that I can use a spray skirt with it with a during the cold weather. Is there different cockpit opening designed for the Panthera, or would I be on my own to customize the combing.

Great Designs,



Thanks Walt, there are two sizes indicated on the drawings (as can be seen on the thumbnail images on the Panthera page): one small (54x40 cm) indended for kayak control, rolling, bracing etc, and one large (78x39 cm), more standard sea kayak cockpit. These are simple to adjust to your own criteria.

Dear Björn,

First of all, thanks and congratulations for that great design.

Do you suggest Panthera for a paddler approx. 105 kg?



Thanks Sukru. Yes, the suggested numbers for Panthera are calculated with a low waterline, which I in retrospect believe is too conservative (and I am going to recalculate). A waterline comparable with most of the other kayaks would indicate a designed load capacity of approx 135 kg. Above that every 17 kg sinks the kayak by 1 cm. With a higher freeboard than kayaks like Njord, Frej, Nomad, Najad etc (the surfski influence – surfskis with their open cockpit normally have a higher sheer to keep water out) there is a healthy margin on top of the theoretical numbers.

A though provocing example of kayak's (and paddler's) capacity is Jim Danielsson who started his famous round-scandinavia trip 25 years ago in an Icefloe (load capacity 150 kg) loaded to 240 kg! And did this at the Finnish-Russian borded in the Barents Sea in early April, launching in freezing temps, ice, snow, severe winter storms, along an uninhabited and dangerous coast.

So Panthera will be fine for touring, excercise and play ;-)

Hej Bjorn,

I really (really !) love your designs and hope to be able to appreciate one in the .. "flesh" soon. I'm intrigued in particular by Panthera, which I consider building during the coming winter. Before committing though, I would appreciate clarification with the followings: I'm 75kg and 1.75m; what would be the ideal dimensions of Panthera design in my case ? I would prefer a slightly shorter version, around 5m LOA - will that be OK in your opinion ? I intend to enjoy the kayak on the Danube river for day trips and, occasionally, in the Ionic Sea and Black Sea.

Thank you !

Thanks Daniel. Yes I think the Panthera would be fine for you, shortened to approx 500 cm. The capacity decreases from 130 kg to 116 kg, which means that you will have a net load capacity of 20-25 kg to the design waterline. And should you for some reason stuff it with 50-60 kg gear it would still float and be maneable, but a bit wetter in waves ;-)

Bear in mind though that Panthera is of surfski origin and thus need a rudder to perform the way intended.

If you (like me) prefer an adjustable skeg, you might take a look at Frej instead.

Hello Björn,

I'm very interested in your Panthera. I consider building this boat and use for fast week trips, with a 20 kg cargo, occasionnaly a bit more., I want the fastest boat I can manage, but as I'm 67 kg I' wonder if the design is a too big for me, (especially if I exercise with no cargo), and if I'd have to shorten the boat or if it's not necessary. I'm very reluctant about modifying your design by myself. Thanks for your answer.


The Panthera would be fine, but with a capacity of 130 kg it would float a little high in the water when you have no cargo. But most kayaks commercially available are also designed for paddlers around 80 kg, so that is a problem you will face with most kayaks.

You can shorten it slightly (perhaps down to 533 – 2 cm less distance between the molds when you attach them to the strongback). The obvious consequence with this is that you loose approx 2% of the top speed, but you will also benefit from a slighly better maneuverability.

The Panthera is deigned to be used with a rudder (the surfski influence).

If you prefer to handle your kayak with an adjustable skeg, the best alternative would be a Njord.

Hello, Bjorn!

Can you please let me know some figures about the stability and speed of Panthera? Unlike other models of yours, such information was not given for the wonderful kayak. I am planning to use this boat mainly on the Danube and the Black Sea, as well on the Aegean

I see from the above comments that I have a compatriot from Romania interested in building the same kayak. I wonder if he already started the task and how he proceeds. Would you please pass him my questions together with my e-mail address? Thank you in advance.

Hello Dragos. No order yet from your Romanian countryman (I will pass on your contact data).

I have no final data yet for speed and stability, since I worked over the hull shape a little further after the software had done its share ;-)

But here are the files from the software (drag/speed and stability), which are very close to the final result.

Gokväll Björn,

Undrar hur Panthera'n skulle fungera med en skäda?

Paddlar en Frej idag, men vill ha en "snabbare" kajak för en eventuell HBB-paddling och gillar varken roder till utseende eller dess risk för tekniska problem på långa turer.


Ännu oprövat, men det bör fungera. Jag kan dock tänka mig att det kräver lite mera aktivt pillrande med skäddareglaget än man är van vid.

Ett surfskiskrov, som Pantheras. är normalt helt beroende av ett effektivt roder för att vara hanterbart, dels beroende på att skrovet i stort sett saknar kursstabilitet och dels på att sittbrunnen är placerad rakt över skrovets mittpunkt (centroiderna LCB och LCF ligger mycket nära den geometriska mittpunkten). I en havskajak som Frej ligger dessa centroider en bit akter om mittpunkten vilket ger ett lugnare rörelsemönster (mer av kajakens beteende sitter s a s i skrovet istället för i rodret), men gör det också att havskajaken är svårare att kontrollera i surf.

Gissningsvis betyder det att du får jobba mer aktivt med skäddan för att få tillgång till hela prestandaprofilen: skädda upp lite för att gira, ner lite för att hålla kursen o s v. Men om detta är ett problem är svårt att bedöma utan att prova.

Som potentiell HBB-kajak skulle jag föredra en förlängd (för att kompensera för mindre packvolym) Njord: teoretiskt lika snabb (men i praktiken kan det bli längre dagsetapper eftersom den är lugnare och kräver mindre aktivt jobb i besvärliga förhållanden), liknande lastkapacitet (men mindre känslig för var lastens tyngdpunkt hamnar). Njord surfar sämre än en roderförsedd Panthera, men hur ofta har man grov sjö akterifrån under en långtur?

En roderförsedd Panthera och en stark paddlare kan förmodligen komma till Haparande någon dag snabbare än motsvarande Njord-ekipage, men det sker inte automatiskt. Det krävs en hel del råslit...

is it possible to change rudder on skeg, or it is a bad idea? is there any new information or feedback about how it goes against wind in rough stormy conditions? Bjorn, how do you think Pantera L would be good for 2-3 week touring?

Panthera is designed for rudder, as it has a lot of surfski in the lines and hull configuration.

As with surfskis a lot of the tracking depends on a rudder, and without a rudder, you might have to work the skeg a lot to control the kayak.

Going against hard wind is no problem with Panthera. The pitching in short waves is reasonably easy to manage – again the surfski inheritance.

Panthera L would do fine for fast long distance touring, of course depending on your own weight.

thank you for yor answer, can you explain with skeg and without rudder it is difficult to

keep a straight course or it is difficult to initiate turning? i cant understand of my poor experience. On your opinion, what is better for long distance cruising/expedition greenland style kayak like Nanoq or Pantera, thanks.

With its surfski heritage, Panthera doesn't have a built-in tracking like sea kayaks. With a rudder, you can control both steering and tracking – with a skeg you can just add tracking. This means that you probably will have to use the skeg control a lot to maneuver the kayak: skeg down to go straight, skeg up to turn, down to go straight, up to turn etc – which I would consider annoying in the long run.

Both Nanoq and Panthera will be fine for long-distance touring: Nanoq with a skeg and Panthera with a rudder. Nanoq with an advantage in precision maneuvering close to cliffs and rocks, Panthera slightly faster on long distances.

But you should consider Njord as well. Almost as maneuverable as Nanoq and as fast as Panthera – to me the perfect long distance cruiser.

Hi Bjorn,

I built your Njord last year and have really enjoyed it thus far. True to your word it is a fast cruiser in all weather conditions. The nice low deck is appreciated by my wife who has just about taken over the boat! Therefore, I now look for a second build project.

I would like something around 5m max that is more manoeuvrable than Njord and ever so slightly more stable (but this is not very important, just want to be able to pee from the boat!). Obviously I have considered Frej but would like something a bit different in style. I'm thinking a shortened Panthera L so that I can get the most out of the shorter LOA in speed, have good directional stability in downwind surfing (rudder), and have good manoeuvrability (rudder up). I'm thinking the larger version (L) to compensate for shortening the boat and to give me around 31cm deck height. A comparable commercial boat may be the Taran 16 or Tiderace Pace Action.

I assume a 5m Panthera would be quicker than Frej and possibly more manouvrable (more rocker?). Would you agree?

I'm 75kg, 180cm tall and will mainly paddle empty boat but would like to be able to load it up with 30-40kgs for light touring in rough water.



A shortened Panthera L would be significantly different from the Njord. Slightly faster overall than a Frej, comparable to the Njord, and more efficient surfing than both. Stability on par with a Frej, and maybe (guessing here) as maneuverable as a Frej, but probably not more (more maneuverable than Njord though). Much more room in the cockpit, which I would see as a drawback, but that is debatable (if you excuse a worn expression, Njord is a kayak you wear, but a surfski is a boat you sit on, or in – in that respect, Panthera is quite surfski-like). Furthermore, the Panthera is rudder-dependant than Njord/Frej are skeg-dependant. You may only occasionally use it with the rudder lifted – the reason being that a surfski hull is a thorough-bred with an efficient rudder replacing the directivity that keeps sea kayaks calm and easy on track.

So, compared to the Njord you get approx the same speed overall (but you have to work a little more with control), more room, more maneuverability and more stability.

Compared to the Frej you get more speed (especially off the wind), slightly more room, approx the same stability and (with the rudder up) the same maneuverability (rudder down you have more control surfing but at low speed Frej will outperform a Panthera).

Hej Björn, finns profilritning för Panthera (för att skissa på färger och utrustning i t.ex.Illustrator) som t.ex. för Njord? mvh Jonas

Det hade jag missat – men nu finns den!


I've seen some projects where one of your kayaks has been built in three separate parts: bow, stern and cockpit. I'd like to ask about the mechanism you use to join everything together. Is the strength of the boat significantly affected? Does it add a lot of weight?

A lightweight, wooden kayak which is easy to store & transport could solve a lot of problems for me.

I have not built a kayak in sections. But others have. Look fx at Rune Eurenius' Sea Racer (a very good technical solution) or Dan Caouette's Black Pearl (as always, fantastic overall quality).

Of course, the kayak will gain one or two kilos in the process (doubled bulkheads, strong wooden members to take the sturdy metal bolts).

But well constructed the strength is not noticeably affected.

Great - thanks for the links :) If I build a kayak it will be used at sea and so it will have to be tough.

What a fantastic range you have! Lots of choices. The Panthera looks like my ideal fast tourer with plenty room for 1-2 weeks supplies. The Najad is on my shortlist too.

Thanks, Noel. These are two fast tourers, designed for rudder, with a good and predictable behavior in open sea, and with a decent room for supplies – Najad slightly more, Panthera slightly less (my kayaks are generally fast tourers rather than full-blown expedition kayaks and I support the idea of fast and efficient cruising in a lighter kayak, rather than providing volume for the load needed to compensate for the slow going of a big and heavy kayak).

To me, the Najad is good for a week on the coast during May-October, a couple of days more in inland waters where the water is used for cooking, a couple of days less in the winter months with more clothes and sleeping gear – Panthera typically one day less.

Hi Björn

Do you think it would be possible to shorten the Panthera to around 440cm/14'?

I really like the shape but want something a little more compact. I realise it would loose a fair amount of speed.

Many thanks.

It is possible. Just shorten the C/C distance between the station molds (and of course the distance stem–sta 1, and sta 13–stern).

You will lose some top speed (approx 3%) and gain a little maneuverability – but most importantly: the load capacity will be approx 95 kg instead of 120 kg.

Thank you Björn, I'll be buying some plans soon then....

Hi Björn,

I like your design very much. It is a bit like my current Pace18, but evolved in much more details i can see.

Iam very hooked to the idea to get one built for racing purposes.

I cant build my self, but maybe you know skilled people that could be hired to do the job ?

Second question: how have you handled the draft of the flip rudder ? I have experimented with the smart tracks race rudder, but still i get draft, that I dont have if I only use a fin/skeg.

Have you considered an edition with a rudder underneath like surfskis with a small weedrudder in front ?

Let me hear if you can point me in the correct way to have a Panthera built

Hi Jacob

I have three partners that build kayaks on order from my plans: one in Sweden, one in USA northeast, and one in Finland. In other parts of the world, you have to find someone yourself; a local boatbuilder most likely, or a competent amateur will kayak building skills.

You can use an aft-hung retractable rudder (fx SmartTrack), but more efficient is a surfski-style under-the-hull rudder – both are easy to attach to the Panthera and are indicated on the plans.

Thanks, Björn.

Can you please give me the contact info for the builder in Sweden? Then I will call them to hear more.

This is very interesting, Björn. I am looking to get the optimal speedmachine for oceanracing, so maybe you have small ideas for uptimizing the Pantera design further ?

What was your thoughts about the length of Pantera when you set it to 558?

Do you think the Pantera would be even faster (in the surf) by adding 10 or 15cms ? Or would it be more like a disadvantage in sidewind ? The Pace18 has 3/4 of the weight placed from cockpit front to the front, which makes it very stabile in high waves and sidewind. Its not quite fast enough though. have experimented with adding a fix surf fin on my Pace18 which enabled me to get 1kmt more on the average speed when not using the rudder (smarttrax race). Would that be an idea as an option on the Pantera ?

Petruskajak i Tranås och Tunarps Kvarns båtbyggeri.

Panthera was designed in response to a couple of requests for a surfski with kayak deck. The first one to build wanted a not too long but initially stable kayak and that became the starting point for the hull shape.

If I were to design an optimal speed machine I would have reduced the beam to approx 50 cm and increased the LOA to somewhere around 580 cm.

A surfski-style hull doesn't have the directional stability of a sea kayak and, thus, needs a rudder to be controllable. Of course, a fixed sked turns it into a sea kayak, which may improve the flat water speed, at the expense of the surfing qualities.

Thanks Björn, interresting thoughts.

First, thank you for your answers. I am just a rider, not a designer but I really know what I look for in abilites to find the best for me. With a beam of 50cm only, i am worried it will be difficult to handle in high waves ~ 2-3 meter dunnings.

I will contact the swedish builders for a quotation. Would you be able to make me a plan for 575/580 cm length and about 52cm in width. Weightwise I aim for somewhere between 16-19kgs, with focus on getting more weight distributed in the front than in the tail.

I would love to have a small fixed skeg like in the Struer Arrow design, so it doesnt get in the way when the kayak is laying on the ground, and the rudder as the Smarttracks Race edition.

If I just purchase the plans, can you come with a suggestion of how to adjust the plans to fit my wishes ? (So Petrus or the other builder will know what to do)

My experience is the opposite – the width, 50 cm, means that you have full control of how the hull moves in the waves, while in a wider, more initially stable hull, the waves will control the hull. What you need in waves is a lot of secondary stability, not initial (you don't capsize from an upright position, if you capsize, you will do it from overtaxing the secondary stability).

The hull will get slightly more weight in the front end since the foredeck is higher, but since this is a surfski type of hull (designed that way, to improve speed and maneuverability on big waves) the seating position is above the turning center of the kayak, not behind it, as is the case in most sea kayaks. This means that the kayak lacks the tracking that is an important feature in sea kayaks calm movements in waves – a surfski is more maneuverable and relies on an efficient rudder for both tracking and turning, and can thus perform on waves in ways that would be impossible in sea kayaks.

Due to this hydrodynamical arrangement, a fixed skeg would be counterproductive and will turn a high performance surfski hull into a more middle-of-the-road sea kayak. I recommend that you try such a skeg (tape it in place) before permanently attaching it.

For an additional SEK 350, I can make whatever adjustments you want to the dimensions, to provide Petrus with a correct set of plans – with the caveat that if you want changes that goes beyond my design criteria for the kayak, the responsibility for its performance is yours ;-)

Great, i can follow your thoughts about the beam.

Lets continue detailing via email and phone

I cant find your email address here on the website, Will you be so kind and email your contact info (email and phone) to me,

Contact info in the left col of the about page

...and here:

Tel +46 (0)46 139416

+46 (0)721 979390

Hei Bjørn!

Ski har jeg livslang erfaring med, men ikke surfski, og heller ikke en surfende kajakk. Derfor har jeg lyst til å bygge en slik kajakk i løpet av kommende vinter. Kanskje er Panthera best egna for en surfedebutant?

I beskrivelsen av kajakken er Pantheras stabilitet satt til 3/4 mens den i tabellen over alle dine kajakker er satt til 4/4. Hva er nærmest virkeligheten?

Fordekket er så høgt som 28,5 cm. Jeg trives best med liten sitteromsåpning, og som er gunstig ved rulling. Er det noen betenkeligheter ved et slikt valg?

Pantheran har ungefär samma initlastabilitet som Frej.

Fördäcket behöver vara högre än på Njord och Frej, för att ett surfskiskrov behöver ett effektivt roder och ett bra pedalsystem – och för att kunna manövrera pedalerna krävs höjd.

Liten sittbrunn kan användas, men för Panthera kan det bli lite svårhanterat eftersom det blir besvärligt att nå pedaler och linor för justering framme under fördäck. Så jag rekommenderar en större sittbrunn.

Takk igjen, Bjørn, for nyttige kommentarer.

Jeg innser utfordringen med pedaljusteringen, men også en stor sitteromsåpning vil være til noe hinder. Jeg kan omgå problemet ved å lage en dekksluke over pedalsettet, eller plassere reguleringsmekanismen framme ved sitsen. Et selvbygd pedalsett og underliggende ror (ev. en type integralror) må jeg tenke mer på. Slikt tenkearbeid og eksperimentering tar tid, men er jo halve moroa.

Jeg orker knapt tanken på å gå tilbake til en storblada åre og høy åreføring. Høyere åreføring må jeg finne meg i, men om mulig padler jeg nok surfekajakken med mi kjære grønlandsåre.

Kanskje velger jeg en mer utfordrende kajakk enn Panthera og bygger, liksom Dan Caouette, en Spray med sittebrønn. Mine kajakker, til og med Black Pearlen, har økt sin stabilitet betraktelig denne sommeren. Jeg har nemlig tatt av langt flere kilo over KVL enn hva selve båten veier. Et så tyngdepunktsenkende og helsebringende tiltak anbefales for alle overvektige padlere. Alt blir så mye enklere både til vanns og lands. På langturer øker effekten ytterligere ved at lastekapasiteten tillater tilsvarende mange kilo nær kjølen, (f. eks. store mengder øl, sjokolade og fetmat).

Bjørn, beklager skrivekløa mi.

Jeg har ikke bestemt meg for hvilken av dine surfeski jeg skal bygge til vinteren. Før bestilling av kajakktegning har jeg tenkt å prefabrikkere delene til et ror. Et integralror, som er montert langt nok framfor akterstevn, vil redusere bagasjerommet for mye etter mitt skjønn. Dessuten vil oppdrifta i den utsvinga akterskrogdelen kunne skape et kritisk stort moment i dreiekoplinga. Skal konstruksjonen bli kraftig nok, er jeg redd den blir generende tung. Jeg forbereder derfor å i stedet bygge et underliggende, opptrekksror etter samme prinsipp som illustrert på din arbeidstegning under Bygga/Download. På tegninga savner jeg imidlertid en ørliten, men viktig detalj; en utvendig stopper/flens nederst på den indre dreiesylinderen eller øverst på det faste ytterrøret? Uten en slik stopper vil vel dreiesylinderen sammen med rorbladet bli pressa opp av sin egen oppdrift og/eller av trykkstøt? I så tilfelle vil ikke bladet komme helt ut av gjemmestedet sitt og kunne dreies som forutsatt. Og snortrekka på toppen vil kunne svikte. Kanskje har jeg oversett noe eller analysert feil. Det har nemlig hendt før.

Jag har laddat upp en mer utförlig version av roderidén på download-sidan, inklusive några bilder från mitt prototypbygge.

På min testmodell är lintrissan tillräckligt tjock för att bara kunna röra sig vertikalt ca 3-4 mm innan den slår i "taket". Men under testerna laminredare jag dit en fals som stoppar rodercylindern uppåt. Lintrissan med sina styrlinor ligger lös i det övre cylinderfacket och man kan släppa på lyft/sänk-linorna och dra ut rodercylindern med roderbladet för service (t ex dra ut roderaxeln och byta roderblad), medan lintrissan ligger kvar under däcksluckan. För detta behövs inga verktyg – roderaxeln hålls på plats i roderschaktet och rodercylindern av lyftlinorna.

Det här fungerade bra vid de tester jag gjorde. Däremot var roderbladet på prototypen för litet för att fungera som tänkt – blev ett racingroder istället för ett surfskiroder ;-)

Det blev sedan inga fler rodertester. Jag fick andra kajaker och utveckla, bygga och testa – kajaker med justerbar skädda istället för roder.

Så rodret får nog tills vidare betraktas som en tämligen otestad idéskiss – en som fungerar bra mekaniskt men som är oprövad i en relevant storlek.

Takk Bjørn for rekordrask oppdatering.

Dermed falt alt på plass. Denne, for meg, nye tegningen sammen med fotografiene viser alle deler tydelig. Min versjon vil ikke bli så flott. I stedet for å støpe innmaten, har jeg tenkt å bygge den nesten bare av tre, så enkelt og raskt som mulig.

Jeg har nylig rodd en vanlig robåt på garnfiske. Den har bare støtte for helen, noe som belaster beina ugunstig. Hvis skrogbredden gir plass nok, vil jeg derfor lage fast fotstøtte ved hver reling og et sett rorpedaler mot midten - hjemmelagd og fleksibelt. Dette blir en surferullekajakk med sittebrønn og sarg. Under padling på smeltevann fra Jotunheimens isbreer og på høyfjellssjøer er denne tradisjonelle løsningen å foretrekke. Det blir neppe noen sydhavssurfing her i mine levetid, skjønt klimaendringene er merkbare.

Ja, det är viktigt med fotstöden. Precis som när man cyklar är det främre trampdynan som skall ha stöd, så att man kan jobba även med vadmusklerna. Annars finns risk för kramp i benen vid vid längre paddlingar.

Den numera vanliga lösningen för pedaler är att göra merparten av pedalen fast och bara en övre tå-manövrerad del rörlig. – en tämligen välfungerande kompromiss mellan bra avstamp för foten och rodermanövrering.

Jämfört med de gamla pedalsystemen (helfotspedaler, fästa i nederkant, eller ännu värre, glidande fotstöd direktkopplade till styrlinorna!) är det en riktigt bra lösning.

Bra är också VKV:s gamla "svängel" – en fast, högt placerad fotbräda med ett spår i mitten där en "rorkult" sticker ut. Denna skjuts i sidled med fötterna för att styra. Finessen är bland annat att fotbrädan kan justeras fram och tillbaka utan att styranordningen behöver röras. Detta fungerar förstås bäst i en racing- eller maratonkajak där man använder rodret främst för att hålla kursen, men lite sämre i en surfski där rodret används kontinuerligt för att kontrollera kajakens hela beteende.


Jag väger ungefär 65 kg och är en skicklig paddlare. jag är ute efter en kajak som kan användas för träning och någon enstaka motionspaddling. Jag använder vingpaddel. Går det att anpassa Panthera så att den fungerar även för oss små paddlare, även när det blåser. Jag tänker att man kan korta den till 530 cm. Sänka däcket någon cm också.

Är det svårt att göra den någon cm smalare?



Magnus, det går alltid att anpassa. Längden är inga problem att ändra, men på bekostnad av lite fart. Höjden på däcket är också relativt enkelt att få till – men det behövs förmodligen inte. Pantheradäcket är lägre än de flesta motsvarande kajaker och inte högre än vad som behövs för roderpedalerna. Bredden är däremot knepigare. Generellt behövs en omritning av hela skrovet för att ändra bredden utan att det uppstår formfel som påverkar egenskaperna. Men ett "fulhack" som funkar hyfsat bra är att köra de relevanta partierna av ritningen i en kopiator där höjd- och breddimensionerna är individuellt justerbara. De småfel som kan uppstå är lätta att korrigera under slipjobbet.

Jag kan också om du vill justera måtten efter dina önskemål. Ritningen kostar då 1500:- istället för 1000:- (justerjobb + extrakostnaden för en ritningsomgång (ingen mängdrabatt från tryckeriet)) och en eller två dagars extra leveranstid .

Men kan du tänka dig en surfski, tror jag att en kortad Spindrift skulle vara tämligen idealisk för dina behov: enkel att använda, snabb och utmärkt i vågor.

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