RoyStuart.biz

Steampunk Hotcurl in NZ Kauri and carbon fiber

2016-06-27T07:07:00.001+12:00

Following up on the Steampunk Hotcurl build, here are the finished pictures. There won't be anymore as the board was sold on commission, unless some clever person manages to get some of the board in action, that is. Overall the hotcurl took about six months to complete, although there was a month or two of planning and design which really should be added to that, but that sort of thing is hard to blog as pictures tend to be theoretical and possibly uninteresting at that stage.

The design stage for these unique boards is of high intensity as it requires deep thought. Even though I have built this type before, some new innovations were added in as I refined the design from its predecessor: the nose was pulled in; the front single fin became a gull wing and the curve going into the tail was smoothed so that it virtually starts just behind the nose,

The vent was sourced in Australia, being smaller than the hand operated vents I usually use, and the leashplug was custom built by an engineer who specialises in hotrods (cars).

There is a bit of a buzz about hotcurl designs following Roger Hall's experimental approach, and some guys at Surfer have started raving about the way the tail moves under the water rather than on the surface. Yeah but I have been talking about displacement tails since 2008 , when I named the feature in an effort to explain the unique performance these boards offer. I realised that the feature needed a better name while the 13 footer went on tour.. Before then, I was aware that 'sinker tail' was not a very sexy name and I just referred to them as extreme pintails, which I started building in 1998.

I started laying the panels up around Christmas time

Please feel free to click on the images for a full screen experience:

An extreme pintail with stainless steel leash plug

...and a carbon fiber set of fins. more on tunnels here

The bi-axial panel made for a chatoyant display of grain direction.

Ultra shiny ready for the customer's birthday party

The Kauri I used was a 150 year old tree, knocked over in a storm

My favorite swooping nose on a digitally designed planshape

Rail is a down rail

This board is going to fly.

Check out those fins. The layers subtly wink as they are moved around.

The only problem is what am I going to build next?

More on the construction of this hotcurl board

Damascus steel? No. Carbon fiber!

2016-03-21T09:16:00.000+13:00

Written by:Emma Allison on 21/03/2015

Damascus Steel and Carbon fiber

Blade smiths in medieval Syria used a special steel ingots imported from India along tortuously long trade routes. They folded and hammered the mysterious and well guarded alloy from the Tamil Nadu into legendary blades which upon analysis reveal the presence of carbon nano-tubes. The carbon and other trace minerals such as Vanadium and Tungsten made the steel very resilient, and many present day sword smiths try to re-discover the lost process.

Recently we were commissioned a Steampunk wooden surfboard and we promised to keep you posted with developments.

Sparks fly as the panel is cut

The fin shown here is only partially shaped. Just to give some perspective, the panel is custom-made by C-Tech from a minimum of thirty layers of carbon fiber oriented in different directions. We completely blunted at least thirteen blades designed to cut steel while using two different jigsaws. Roy ended up using the AEG battery operated jigsaw and we were running the re-charger continuously, charging four batteries from empty as they were used. It took three hours just to cut this fin out. Every few millimeters the blade had to be cooled in water, as sparks would start to ignite the carbon dust below, and every two inches or so the blade had to be replaced. That was Thursday afternoon. We might investigate water-jet cutting in future, but needs must.

Shredded sandpaper

Yesterday we started shaping the foil. We used a rotary sander and a smaller orbital sander. Both Makita brand. There was no question of doing this by hand, each stroke needed to be repeated many times and the power tools simply do this efficiently. Heat was not so much of an issue this time. Sandpaper was changed frequently. Five hours and many shredded pieces of sandpaper later we had this shape in our hands...

Credit: Emma Allison
Roy Stuart Surfboards

Layered carbon fiber surfboard fin

Oh! The beauty.

What's even more interesting is the orientation of the different layers of Carbon fibers has given the fin a cat's eye effect similar to the chatoyance of some woods. The fin started shining like a gem as the sandpaper became finer. It was like uncovering a precious object from a rough ashler.

Check out the iridescence here.

Stay tuned for more updates on Roy's progress with the million dollar Steampunk Hotcurl surfboard

Steampunk Hotcurl surfboard

2016-02-18T08:50:00.003+13:00

Steampunk Hotcurl surfboard. A Victorian nostalgic concept board, with NZ Kauri wood, Carbon fibre fins and metal fittings by Roy Stuart.

Next in the million dollar line of custom surfboards, we have the Steampunk Hotcurl. Steampunk is a Victorian nostalgic movement, which incorporates old style materials in imaginative configurations.

Surfing of course was virtually stamped out by the up-tight Victorians, as they viewed the thousand year old Hawaiian sport as a lewd past time, with naked women cavorting in the shore-break. Of course we know that surfing is more than that, and we liked the design brief. The idea being: something old combined with something new. The Kauri used for this wooden surfboard project is over a hundred fifty years old, so the sapling was growing in a similar age as the concept of this surfboard.

Steampunk is a way of expressing a nostalgia without having the constraints the Victorians had. We can benefit from new technologies such as Carbon fibre, or CAD design for the outline, or the latest in Epoxy additives which renders the polish mirror smooth, for example. The steampunk idea comes in with the finished article looking and feeling like the 'real' thing.

As we speak the client is choosing metal deck hardware, having a choice of brass, stainless, and electro-polished stainless, which has a graphite metal lustrous look to it. The fins are going to be hand shaped from carbon panels, so the fins will be a new material with an old world hand polished look to it.

We chose the Hotcurl design as it would suit a Victorian gentleman, who would want a board which is easy to ride, with no awkward learning curves involved when taking the board out for the first time. The board has a distinct sweet spot, which means 'stand up and go', in surfing terms..

Applying the final gloss coat.

Stay tuned for more pictures as the board progresses. We might have to get dressed up for this one!

New Zealand Kauri flames with chatoyance, 'the cat's eye effect'

Check out the start of this project, when we milled the Kauri and constructed the board

Steampunk Hotcurl surfboard Roy Stuart Surfboards Manufactured by: Roy Stuart Model: Steampunk Hotcurl Product ID: Steampunk 1200000 NZD New

Surfboard fin scaling? How to approach it..

2016-01-19T08:17:00.000+13:00

Surfboard fin scaling? How to approach it...

In response to Bert Burger: https://vimeo.com/129849316 Why does fin area not scale directly according to rider weight?

Quick trick surfboard stand

2015-12-28T12:09:00.001+13:00

A surfboard stand made from japanese cedar, it has shelves for tools and can be turned upside down to give a narrow glassing stand... this way up for shaping.

Kauri/Paulownia 10'6" 'Hotcurl'

2015-12-20T08:08:00.001+13:00

Dimensions are 10'6" by 27" by 2". This million dollar surfboard is a commission using 150 year old, second generation New Zealand Kauri harvested in the Coromandel. Kauri is a revered timber for its beauty and even density. It grows into huge straight logs given plenty of time. Pictures of loggers in the old days show one log filling an entire railway carriage . That particular tree must have been thousands of years old.
Conservation of Kauri did not start until the first world war, when the 'public' realised that the beautiful Kauri forests were rapidly dwindling to small pockets in nearly inaccessible sites. . The timber I am using here came from a regrowth log felled by a storm. There was a massive crack up the middle of the slab By milling the slab into the pieces you see here I was able to salvage good clean timber from around this crack.

I had the slab milled to 4 mm on a new machine at a joinery business down the road.

Sorting through the stack.

I soon had a panel with a slight diagonal grain direction .

A peek at the interior of the board. These Paulownia panels take longer to lay up.Each piece is cut individually,

The first lamination is eased into place and rests there for 48 hours before applying the epoxy.

Note the other panels waiting in the background

Ah , the parallel profile aficionado will recognise a 'quick trick brick stack'

A ton of bricks is lifted into place. This process is reversed the next day only to add another panel and replace the bricks. I am busy clamping the extra kick in the nose.

Ta-daah.

I first built a Hotcurl design in 1999 . This board will be the fourth version. I adjusted the nose slightly and smoothed the rail line to an even curve from where I am holding the board approximately .

I always like seeing this angle in photos . The plank lines give a visually exciting movement to the design.

Please check back for finishing pics. The Kauri will 'pop' magnificently.

Also check out the million dollar ride which was the previous version of this model.
The archive suitcase of photos yielded this snap of the 2000 version.
When I first thought about the concept in 1994 I called it the Thrusterbuster. This was a reaction to the industry's dogged adherence to the Thruster .

The witch doctor asymmetrical surfboard

2015-12-06T09:35:00.004+13:00

A trend in surfboard design is to make asymmetrical designs. If one uses a sideways stance, then one's body is effectively not symmetrical. The feet only face forward after all. This board is my second goofy design. The idea is that the backside rail needs more curve than the frontside. This session is my first surf on the board, and I think the design has promise.

The witch doctor asymmetrical surfboard

The AS371 asymmetrical surfboard at Mount Maunganui.

For a view from the tail of the witch doctor design and a quick snap taken during final sanding
If you liked this session , here is a video of the first asymmetrical board I built at the same spot.

S371 asymmetrical 'Witch Doctor' surfboard launch

2015-11-29T15:28:00.001+13:00

Surfboard aerodynamics and the bullet nose.

2015-10-31T14:30:00.002+13:00

Surfboard aerodynamics and the bullet nose.

Written by: Roy Stuart on 31/10/2015

The effects of air flow on surfer and board can be significant. Assuming that the wind opposes the movement of the rider, it's obvious that unwanted drag will occur. What is not so obvious is that the surfboard nose can, under the right circumstances, produce a beneficial lifting force which will reduce the load on the hull and possibly the wetted surface area also, for an overall reduction in drag. For this to occur the surfboard nose has to have a suitable shape. Pointed noses are not ideal as they trip the air flow, causing a detrimental vortex. We use a 'bullet' nose and a thicker nose section, which allows a smooth flow over the maximum possible range of angles of attack. The surfboard tail shape is also significant as it changes the angles at which the nose is presented to the oncoming flow.

#roystuartguns Why is a round nose better?

Round noses work better.

In this video Roy explains some of the reasons why. You can experiment with this concept while driving your car. Stick your hand out of the window and keep it flat. your hand will 'catch' the wind and you can feel the force of the wind pushing your hand further as it catches, this simulates the wide flat pointy noses of conventional boards. Now ball your fist to simulate a round bullet nose a la these Roy Stuart guns. Your hand feels stronger and less catchy.
http://www.roystuart.biz/2013/02/aerodynamics-in-surfing.html?q=aerodynamics

Surfing a Whale Bumped Gull Wing Fin at Manu Bay, Raglan

2015-10-27T00:17:00.001+13:00

A compact version of the 16 series Ghost: A mid point at the centre of the board... 9'3" by 24" with 3d printed Gull Wing single fin, from a US blanks Yater longboard blank, with 3d glass. The glassing feels like the weight of a classic longboard, but with incredible strength. This board can be knocked around by a band of teenagers for example (three sons in their twenties at the moment) 'Flat' accross the board, bottom with a concave in front of the fin, for a bit of directional, towards the fin exit water movement, Moderate rocker, with a variety of waves in mind, allowing for some size until the buoyancy gets too much for the ride, however the buoyancy is great in head high to one and half times overhead, at which point the board gets harder to manage. It's a juggle, as thinning out the design will make this board flabby and hard to catch waves on in smaller waves. Needs must. The broken look of the gull wing made for a pleasant surprise. Whale bumps improve the design in my opinion, making for an extra sensitive and in-command feeling when up and running.

Overall this 3d printing of fins has expanded the iteration speed of models and mastery of foil designs. AMA about foil history and nomenclature. How wartime aeroplanes were improved by light-years, i.e. the difference between losing and winning the war, through similar study, and how size of the object (Surfboards) dictates the foil shape, size, and philosophy of the design.

Surfing a Whale Bumped Gull Wing Fin at Manu Bay, Raglan

9'3" by 24" with gull wing Whale Bumped single fin.

Mid Length Surfboard Madness

2015-10-24T16:34:00.003+13:00

Eight feet by 25" by 2"@44 litres with GullWing fin and tunnel.

Mini quad slab for Robin

2015-10-18T17:04:00.001+13:00

This little slab is for Robin, aged 9yrs, intended for whitewater riding with no fins or standup with a minimal quad bonzer setup.

Planshape cutting from solid slab

Defining the single concave

Bonzers @19 and 8 degrees

Marking out the Futures boxes

fitting fin boxes

epoxy 'spackle' coat

Ten ounce glass x two on the deck

Filler coats

Concave!

Boogie board on steroids

Roy Stuart

Island traders

Designer, construction manager

Roy after shaping a mini Simmons type surfboard for his youngest son.

75 Princes st,

P.O. Box: 3411

Putaruru, Waikato

3411

New Zealand

admin@roystuart.biz

+6478821560

'Beavertail' 8'8"

2015-10-18T09:59:00.001+13:00

She's 8'8" by 24", with a very low rocker.

Does water temperature affect your surfboard fin performance?

2015-10-13T08:35:00.003+13:00

Yes it does.

Here is a subject which has taken me years to wrap my head around. To understand, one needs to grasp the concept of a Reynolds number i.e. the relationship between momentum forces (lift) to viscous forces (drag). The resulting number does not have a dimension (meters or litres for example), but is just a number. By calculating a Reynolds number one is able to compare foils, and understand which flow regimen we are talking about. (Water vs Air for example)

When water temperature decreases, the viscosity of the water increases. Viscosity can be visualized as 'thickness' , so honey is more viscous than water. Water gets thicker when it gets colder. A drop in temperature increases drag and turbulence while decreasing the extent of smooth laminar flow.

Garrett misjudged the temperature

A typical example

Shown below is the effect upon a fairly typical single fin foil of change in water temperature from 20 degrees Celsius down to 1 degree Celsius. The speed and chord length in this example are kept constant.

As can be seen the Reynolds number is much lower in cold water, this shows the increase in water viscosity.

So here are the calculations are specific for this foil.

RAF 27 AIRFOIL (raf27-il) Details
(raf27-il) RAF 27 AIRFOIL RAF-27 airfoil Max thickness 9.8% at 30% chord. Max camber 0% at 0% chord As you can see the temperature drives the viscosity (thickness) and thus the Reynolds number .

Water temperature 20 degrees C

Velocity	m/s	26.843 mph	43.2 kph
Chord width	m	0.19685 ft	2.3622 in
Kinematic Viscosity	m²/s	1.054e-5 ft²/s
Reynolds Number	735,166

Water temperature 1 degree C

Velocity	m/s	26.843 mph	43.2 kph
Chord width	m	0.19685 ft	2.3622 in
Kinematic Viscosity	m²/s	1.769e-5 ft²/s
Reynolds Number	438,009

How does that look on a graph?

The red line in the two graphs below represents the higher water temperature, and the purple line the lower temperature.

As can be seen here in the Cl/alpha graph ( which shows changes in lift vs angle of attack) at lower water temperature the fin will stall earlier (stall is seen where the lift suddenly drops, as angle of attack increases).

In cold water the fin will stall at about 11 degrees aoa and in warm water, at about 14 degrees. this is a significant difference.

at lower water temperature the fin will stall earlier (stall is seen where the lift suddenly drops, as angle of attack increases).

Below we can see Cd/alpha, or drag vs angle of attack. As the angle of attack exceeds 7 degrees the drag produced in cold water soon becomes double that of the drag in warm water, and the difference increases as the angle of attack goes higher.

As the angle of attack exceeds 7 degrees the drag produced in cold water soon becomes double that of the drag in warm water

How does this affect other foil types?

Results vary widely depending upon the kind of fin foil used, and the chord length of the fin. Increasing the chord length of the fin raises the Reynolds number and is one way to overcome the angle of attack limitation seen in cold water. This means that a fin with a longer fore and aft length would suit colder water. (ever wonder why Hawaiians bomb out at cold water spots such as Mavericks? Could be their habitual fin choice) All else being equal however, increasing the chord length will also increase skin friction drag. So a heavy handed base length change without doing the Math might not do the job as expected.

Increasing speed also increases the Reynolds number.

So, increasing speed, water temperature or the chord length of the fin all have the same effect on the Reynolds number. Chord length and water temperature are fixed during any given session. Speed however, constantly changes and the surfboard fin is required to operate over a range of speeds during a ride. A fin which is optimised for low speed will be larger than is necessary at high speed, and vice versa, and a fin which is optimised for warm water might experience stalling issues in cold water, when used at the low end of the speed range.

The cold water dilemma

Here is the key: Issues are most likely to become apparent in cold water when using high aspect ratio fins with short fore and aft chord lengths. (Remember those over confident Hawaiians ?)

High aspect ratio fin (warm)

Ideally, when travelling, a different fin or set of fins will be needed for different water temperatures. the foil section can be changed, but the most obvious way to alter the fins is to use a longer chord in cold water, and a lower aspect ratio fin.

Low aspect ratio fins (cold)

Thanks to airfoiltools.com for the graphs, foil section and Reynolds number calculator.

How do Reynolds numbers change with fin thickness?

Did you like this in depth analysis? Try Single fins and asymmetry

For a more basic glossary of terms used when talking about surfboard fins .

The S371 Gun surfboard

2015-09-09T18:18:00.003+12:00

Asymmetrical 11 foot 'gun' surfboard at the resin coating stage:

Million dollar rides: Hotcurl surfboard

2015-08-27T20:04:00.001+12:00

Hot Curl 10-6 from the Roy Stuart collection.

Aerobatic foil plan shape.

Feanorian script 'Curl'

Empress wood, gold. stainless steel.

Inspection port detail.

The engine room.

Postmodern Steam Punk.

Hotcurl: 10-5 by Roy Stuart.
Created: 2013
Status: Restored
Price; Offers over US$1 Million

Tunnel fins for FCS tabs

2015-08-18T14:52:00.002+12:00

Tunnel fins deliver incredible drive. We have been designing, building, and surfing tunnel fins with great success since 1997.Our favourite application is to use them in-line behind single fins.

Tunnels are available now in limited numbers.

Or contact Roy admin@roystuart.biz

A six inch glass tunnel with FCS tabs

To read more about tunnels try these Tunnel fin observations

Ever wondered what the water does around tunnels? VORTEX generation in tunnels

Roy's wonderful world of tunnels, a photo gallery from the archives.

Roy circa 1984

2015-08-17T21:21:00.000+12:00

En route to Ruapuke from Raglan with cousin Mike, 1984

Single finned surfboards: how about asymmetrically foiled fins?

2015-08-16T18:35:00.000+12:00

Asymmetrically foiled fins are the norm for rail mounted 'side fins' on multi finned surfboards, and have been for at least the past 40 years. The principle used is that during a turn, the fins on one side of the surfboard are dominant, so the foil can be optimised for the positive angle of attack which they are experiencing... when the angle of attack becomes negative for those fins when turning in the other direction,it doesn't matter as they will often be lifted out of the water as the board rolls.

With single finned surfboards it has always been assumed that the foil must be symmetrical, as the same fin has to do all the work whether the board is turning left or right.

I was recently shaping the asymmetrical '371' single finned surfboard shown below. The board is designed for 'left handers' i.e waves which break to the left when viewd from behind. Thyat'swhy the planshape has less curve on the inside rail ( the rail which will be engaged when the board is trimming left). I want that rail to be fast and low drag. , and am not concerned about the turn radius, in fact I'd prefer the turn radii to be greater for high speed adjustments to the line. The reduced outline curve on the left will help to achieve this.

When 'cutting back'it would be nice to have more planshape curve in order to turn more tightly. In addition using the narrow outline from the left handed railon both sides would make the board very narrow, requiring greater thickness to get the necessary volume... something I'm keen to avoid as it tends to make the board less stable. So, the right hand side of the board can use more curve and width, as shown.

Supermarine 371

The design is 11 feet long by 22.25" wide. If the left hand rail were used only i.e.on both sides, then the board would only be 18 inches wide. If the right hand rail were used on both sides she'd be 27 inches wide. Both theoretical widths are within the practical range,

While shaping, it occurred to me that since the surfboard will be using the left hand rail ( effectively 'turning left') most of the time, especially in fast breaking waves, there's a potential advantage to be gained by foiling the single fin asymmetrically. Provided that the efficiency gain due to the asymmetrical fin being flown 'right side up' while going left is greater than that lost by flying it 'upside down' when going right, there should be a net gain. Because the surfboard will be going left most of the time (and arguably requires greater efficiency when doing so as it needs more speed to race the curl than when 'cutting back') then the asymmetrical foil should win.

Of course not all asymmetrical airfoils will be suitable. Many are only designed for 'right way up' flying, and perform so badly inverted that they would be worse than useless when turning right.

Here's one such foil:

E174

The lift/drag graph below shows that when the wing is inverted ( or rather the effective angle of attack becomes negative i.e. lift is less than zero) the lift/drag ratio declines rapidly and the wing enters the stall.

Instead we choose a foil section which performs well 'inverted'. The chosen foil is less markedly asymmetrical but it has a nice low drag bucket at up to four degrees angle of attack, and approximately a third less drag in this zone than at minus four degrees angle of attack.

As luck or good design would have it this foil section is the same one which we used for the surfboard planshape.

Lift vs drag graph

The graph below shows that lift vs angle of attack is more or less constant throughout the range from negative 10 degrees to positive ten degrees angle of attack. So the fin will feel very similar to a symmetrically foiled fin when in use. That's good.

It's worth noting that the graph also shows that effective zero angle of attack ( where the fin produces zerolift) will be at approximately minus 1.2 degrees,so the fin should be offset from the 'centreline' of the board by that much, all else being equal.

Consistent rate of lift production through negative and positive aoa values.

Here we can see the low drag advantage flying the foil upright vs inverted, as angle of attack changes. What this foil should deliver is an advantage over similar symmetrical foils throughout the full range of angles of attack, and throughout a typical range of surfing speeds.

|Speed is represented here by the coloured lines... red is a reynolds number of 500,000 or 9mph in water of 10 degrees C, gold is a reynolds number of 1,000,000 or 22 mph.

Water temperature is also relevant, as changing the water temperature from 0 degrees to 20 degrees C increases the reynolds number by 65%. This means that for some foils a fin with substantially shorter chord can be used in summer or in warmer water generally. It's not an issue in this case as the low and high reynolds numbers give similar results in the required speed range. Going faster than the modest 22 mph which the airfoil tools plotter allows us will obviously not be an issue.

Drag vs angle of attack showing the low drag bucket from minus one to four degrees angle of attack.

Yes,as you have probably guessed, we are Supermarine Spitfire crazy, and are using the 371 Supermarine Spitfire foil for both the surfboard planshape and its fin foil, in addition to a Spitfire wing inspired elliptical planform for the fin.

Hence the board will be the 'Supermarine 371' model.

Many thanks to the creators of airfoiltools.com

.

Vort-X tunnel fins: is there really a vortex?

2015-08-11T16:20:00.004+12:00

According to my visualisation of half pipe tunnel fin flow, there's a slight but significant twisting of the flow as it passes through the enclosed pipe. I've been talking about this for many years, and some people have been sceptical about the existence of this vortex.

Yesterday Hans from the finfoil project posted images from his computer flow modelling of a half pipe tunnel fin, proving that the vortex is real.

The pictures show a tunnel fin with an angle of water flow attack at ten degrees:

vort-x tunnel fin for surfboard flow modellling image 1

Aside from the drag reducing benefit which the tunnel gives ny absorbing and managing the chaotic turbulence which leaves the trailing edge of the leading, planar fin (If it doesn't have leading edge vortex generators) the vortex induced by the half pipe tunnel has another advantage.
Normal flow inside a pipe produces drag inducing spanwise vortices. In the case of the half pipe tunnelhowever, the twisting motion induces beneficial lengthwise vortices instead. A full cylinder won't do this, it's the asymmetry of the half pipe which causes it.

The dreamliner aircraft uses a tunnel with trailing edge undulations to improve flow mixing and reduce drag.

Why use a tunnel fin?

A tunnel fin overview.

Asymmetrical longboard gun surfboard 66/838 gets wet.

2015-08-08T17:44:00.001+12:00

Here are the first few test waves on the 66/838 ten footer. On the first wave it can be seen that I'm riding from way too far back on the board, this causes an imbalance and some pitching and pounding through the chop. The next two waves are better but I still need to move forwards a few inches.

I'm also failing to use the shock absorbing capabilities of my legs enough, that's because I'm on a smaller lighter board than usual, so am less relaxed and stiffer as I try to keep control.

The board is extremely lively for a ten footer. It has a unique carving feeling when the tail slices during turns. It feels very accurate and drag free... the pintail gives sensory feedback through the carve as it runs underwater like a fin. The last few inches of the tail have a strut foil cross section which allows it to travel quite happily underwater.

The rail channels give excellent hand grip when rolling the board under breaking waves, and the roll under capability is good for such a relatively light board.

My gut feeling is that the board will prove to be exceptional once I have the 'sweet spot' dialled in. She was four months in the making and is definitely a 'keeper' for the quiver.

Incut tail with spitfire fin

A 9 inch spitfire fin with bumpy leading edge and NACA 16-012 foil is being run at present, with no issues at all, next I'm going to drop down to an 8 inch Spitfire placed slightly further back, to see how it feels with a smaller fin.

Asymmetrical planshape detail

Ghost surfboard evolutionary array

2015-07-09T15:45:00.001+12:00

#16 'Old faithful' The original Ghost design, first conceived and made in 1998. With 17 years of testing in all conditions behind her the faithful 16 has proven to be a faultless and reliable performer in every imaginable situation. Features the constant radius tail which is the cornerstone of the 'extreme pintail' displacement tail innovation.
#64A 'Straight tail' A no compromise high speed down the line racer with ultra precise handling. The 64A has a straight line rail through the tail and a slightly more forward riding position than the 16, with reduced tail area for even better pitch dampening and rider security.
#66 'late incut' As a direct development of the 'Old faithful' 16, the '66' model shares the central riding position of the '16' as well as its legendary handling qualities. The ride has been enhanced by the concave tail 'incut' which improves water flow mixing and release at the pintail for greater speed, while also creating a higher radius 'hip' at the aft zone of the riding position for faster turning response, and more sensitive pitch dampening.
#838 'early incut' Here the concave 'incut' innovation is applied to the forward driving position of the 64A . Thus 838 further enhances the accuracy, sensitivity and secure handling of the 64A's high speed carving nature.
#66/838 'asymmetrical' for goofy foot & #838/66 for natural foot Surfboard asymmetry reflects human asymmetry, it's an advanced frontier in intuitive, rider friendly, stance based ergonomic performance. Ghost 838/66 and 66/838 'asyms' use a new theory in asymmetrical design specifically suited to longer boards for extreme waves.
#roystuartguns A new paradigm in asymmetrical surfboard design.

Raglan surfing with Suzie Q

2015-07-08T15:30:00.001+12:00

Gun portrait

2015-07-07T18:19:00.000+12:00

Here's the nearly finished 66/838 gun with wolf paw print, after some in the water testing she'll be off to Western Australia to be put through the paces by Jeff Goulden and Heath Joske.

Big wave gun surfboard

Wolf paw and strut foil detail

2015-07-05T16:49:00.002+12:00

RoyStuart.biz

Steampunk Hotcurl in NZ Kauri and carbon fiber

Damascus steel? No. Carbon fiber!

Damascus Steel and Carbon fiber

Sparks fly as the panel is cut

Shredded sandpaper

Oh! The beauty.

Steampunk Hotcurl surfboard

Surfboard fin scaling? How to approach it..

Surfboard fin scaling? How to approach it...

Quick trick surfboard stand

Kauri/Paulownia 10'6" 'Hotcurl'

The witch doctor asymmetrical surfboard

The witch doctor asymmetrical surfboard

S371 asymmetrical 'Witch Doctor' surfboard launch

Surfboard aerodynamics and the bullet nose.

Surfboard aerodynamics and the bullet nose.

#roystuartguns Why is a round nose better?

Surfing a Whale Bumped Gull Wing Fin at Manu Bay, Raglan

Surfing a Whale Bumped Gull Wing Fin at Manu Bay, Raglan

Mid Length Surfboard Madness

Mini quad slab for Robin

'Beavertail' 8'8"

Does water temperature affect your surfboard fin performance?

A typical example

RAF 27 AIRFOIL (raf27-il)

How does that look on a graph?

How does this affect other foil types?

Increasing speed also increases the Reynolds number.

The cold water dilemma

The S371 Gun surfboard

Million dollar rides: Hotcurl surfboard

Tunnel fins for FCS tabs

Roy circa 1984

Single finned surfboards: how about asymmetrically foiled fins?

Vort-X tunnel fins: is there really a vortex?

Asymmetrical longboard gun surfboard 66/838 gets wet.

Ghost surfboard evolutionary array

Raglan surfing with Suzie Q

Gun portrait

Wolf paw and strut foil detail