The King's Ride

Hotkurl: Million dollar ride...

2013-05-25T12:07:00.001+12:00

2013 Hotkurl 10-5 by Roy Stuart:

HOTKURL Teardrop planshape perfection

Voluptuous curve synergy

'Kurl' in Feanorian script 23 ct gold tail detail

Vort-X tunnel & spitfire cutaway fin horsepower

Concave hull with tucked rail edge

The Dream

HOTKURL Displacement tailed planing hull in action

Polished stainless steel vent and 23 carat gold leaf

Empress wood, stainless steel and gold

1.47 million USD

Displacement tailed planing hulls 101: Tunnel or single fin?

2013-05-24T14:24:00.002+12:00

Displacement pintails when correctly designed allow the tail of the board to sink during turns and stalling moves, greatly increasing the versatility, control and balance of longboards. When force from the rider is released the tail lifts again automatically due to a combination of planing and buoyant lift.

It is vital for such tails to have sufficient thickness to allow both a low drag shape ( with soft catch free rails ) when submerged at higher angles of attack and to provide sufficient volume for the required buoyant lift. A narrow low area tail is also needed both for clean underwater running and in order to reduce rail to rail resistance from athwartships planing force leverage.

We have used this principle with great success both on single finned longboards and those also equipped with tunnel fins. The single finned boards use hull based lift only, with a higher proportion of buoyant lift over planing lift. The tails on these singles are easier to sink and have a corresponding softer spring back as the tail lifts, all else being equal. Because of this the ratio between the force required to roll the board from rail to rail and the force required for fore and aft trim is altered in comparison with the tunnel finned tail.

Here's a single finned displacement tailed board, the Ghost 12, sinking the tail during a bottom turn, the aft 6 feet of board is beneath the wave surface, this is achieved with moderate pressure from the rear foot and most importantly from a central riding position which allows excellent balance and gives the tail more leverage during spring back:

A reduction in weight on the rear foot will bring the board back into down the line trim in a 'self tending' fashion, here's the Ghost 12 again:

Dragon 13-9 with twice the weight and nearly two feet more in length utilising the displacement tail. Greater weight increases the force required to lower the tail since the longer heavier nose has a stronger counterbalancing effect. The longer tail also has more leverage, which reduces the depth to which the tail submerges.This is appropriate for the Dragon since it draws longer lines.

In contrast here's the Makaha 12-9 which has a four inch diameter tunnel fin. The planing lift from the tail is greatly increased, the effect is somewhat like stronger or tighter rear suspension on a vehicle:

Both options work admirably and the advantage which the system has over standard longboards can't be over stated.

Unveiling the incredible Hotkurl: Polished stainless steel vent and 23 carat gold leaf

2013-05-24T09:19:00.005+12:00

Hand operated stainless steel vent with 23 ct gold leaf.

Unveiling the incredible Hotkurl: Vort-X tunnel plus spitfire cutaway fin horsepower

2013-05-23T23:30:00.002+12:00

High lift virtual rocker fins on the Hotkurl 10-5. Nine inch cutaway Spitfire with four inch diameter half pipe Vort-X tunnel, fed by a full length single hull concave, with displacement pintail trailing.

Hotkurl Vort-X tunnel plus cutaway Spitfire fins.

Unveiling the Incredible Hotkurl: Voluptuous curve synergy.

2013-05-23T15:36:00.003+12:00

Beauty via pure geometrical design conceived and made manifest from first principles. Hotkurl 10-5 lies in wait for her prey.

Hotkurl 10-5 surfboard curve synergy

Hotkurl 10-5 ready to ride...

2013-05-21T09:12:00.002+12:00

More pictures coming soon

Making the Hotkurl part 11

2013-05-11T19:35:00.003+12:00

Empress wood in amber: resin coating and gilding the Hotkurl wooden surfboard.

Hotkurl surfboard Feanorian 'Curl' script 23 ct gold

Hotkurl 10-5 surfboard 1.47 million dollars

Quantum Mass

2013-05-09T22:24:00.002+12:00

A Weapon of Mass Velocity....

Making the Hotkurl part 10

2013-05-08T15:06:00.001+12:00

Resin coating in progress, note the concave and tucked under edge, shaping has taken a few weeks...

Making the Hotkurl part 9

2013-05-06T21:39:00.002+12:00

Shaping continues...

Roy: can a traditional stance be used on your surfboards?

2013-04-27T18:07:00.001+12:00

Any stance can be used, I use both a relatively forward stance and a sideways stance. My stance is as traditional as any other, and it's not uncommon at present either.

The key is to work within the 'sweet' area, which is more concentrated and central than on mainstream longboards. Longer heavier boards which are well balanced having a more central riding position tend to favour a narrow stance also.

Steve you'll find your own way, if your current methods need to change slightly that will happen naturally and you won't necessarily stand the way I do. I've seen a lot of people ride the Ghost 13 which is a similar board and there were different styles used.

Leroy Grannis:

Tom Blake:

Duke:

Roy:

Bob Simmons:

Update on the 13 foot 'Future Primitive' Ghost Olo tour.

2013-04-26T12:20:00.002+12:00

The broken surf board is now in the hands of Brad Tucker who is taking on the major challenge of rebuilding her. Thanks to Huck and Riebhoff for transporting the project.

From Brad:

"Thanks again for the hand off Huck! Get me that address again so I can send you a Paulownia thank you card.
Roy, I knew in advance I'd be stoked to see this and I was right. Beautiful work and not just aesthetically.
I can see I'm going to learn a lot from this project.
This board was built in 06 or 07 correct? My first impression is this board lasted long and held up amazingly well considering it's age, where it's traveled and the size of waves it's been on.
Other than the big hole in the middle it's in amazing shape. All the internal structure is still tightly glued together. No mold or soft wood that I can find. The outer surface is smooth as if it was finished up last week. No warped or cupped planks. Am I correct this board is unsealed inside and unglassed outside? Wow! Pretty sure that's what I'm seeing.
Anyway working on this project is going to improve my own work I can already tell. This is a treasure box of board building technique to learn from.

Huck and I were making the hand off at the Malibu surf parking lot yesterday. At least 4 or 5 complete strangers walked up and knew exactly what it was. Pretty cool. One guy said he recognized the board from out in the water so he paddled in to check it out. We let them all check it out, pick it up. Big BIG grins all around.

I'll push to get it done over Summer and take lots of pics."

STOKED!
Brad
WSS

Donald B with the Ghost 13 surfboard in Hawaii, November 2008

Eyes on the prize

2013-04-20T16:04:00.001+12:00

Makaha 12-9 at the Point

'Makaha' means 'fierce' in the Hawaiian language, here's the Chinese character for 'fierce'.

Plain D Blues

2013-04-18T18:35:00.000+12:00

The Gilded Dragon 13-9 gliding some unbroken swells through to the inside section at the 'Blowhole' at Mount Maunganui. She covers a lot of distance with ease, both on the outside swell and through the inside.

5am Deal

2013-04-16T23:14:00.003+12:00

Earl 10-6 at Mount Maunganui's main Beach, New Zealand.

Making the Hotkurl part 8

2013-04-16T16:20:00.001+12:00

Shaping continues on the Hotkurl 10-5

Does surfboard flex occur under the rider's front foot?

2013-04-15T18:59:00.001+12:00

Not usually. The reason for this is that water pressure is greatest right under the front foot, and rapidly reduces as it goes aft towards the tail. Water pressure under the front foot is many times greater than at the tail. The high pressure area is like the support used during a land test. Place that support under the front foot and apply as much force as you like and there won't be any flex.

To make the board flex pressure needs to be applied near the fore and aft middle of the wetted surface area, and the tail needs to have a high pressure zone... this is like pushing down on the middle of a board which is supported at the ends.

There are two problems with this:

One is that most boards have no high pressure area at the tail... the tail has very low pressure. With only one high pressure area the situation is like a land test with the board supported at only one end... pushing down in the ;middle' will only depress the tail without any flex. Canted fins or horizontal wings can provide higher pressure in the tail but typical cant is very small and the canted fins are placed fairly far forward which shortens the lever arm and drastically reduces the chance of flex.

The second is that when pressure is placed in the middle of the wetted surface area this moves the high pressure area aft as the waterline length decreases ( because the board raises its nose.)

Another issue is that even assuming that there is a high pressure area at the tail, if the lever arm ( length of board behind the rider's foot) is short then the board won't flex significantly. The amount of flex is greatly increased when there's a long lever arm, for any given force. This also means that a riding position which is right at the tail when turning ( for example on a mal) gives a very short lever arm.

.

Long tails are ideal for surffboard flex.

Here's Savitsky's drawing showing typical planing hull for and aft pressure distribution ( the curved line above the hull). As can be seen the high pressure zone is where the rider's front foot is usually. Moving the weight back moves the high pressure zone back as well.

Making the Hotkurl part 7

2013-04-05T17:52:00.002+13:00

Hotkurl 10-5 with first rail facets shaped:

The King's Ride: Roy Stuart Surfboards

Hotkurl 10-5 Roy Stuart Surfboards

Voyage of Dreams

2013-04-04T14:09:00.003+13:00

Music "David O'Brien-Voyage of Dreams" Audio network

Location Manu Bay Raglan New Zealand

Surfboard 'Makaha' 12-9

Surfer Roy Stuart

Wetsuit Bodyline

Helmet Gath

Videographer Emma Allison

Photographer Jwan Milek

Camera canon 600D

Jim 'The Genius' Phillips on 'engineering' in surfboard shaping

2013-04-04T09:45:00.003+13:00

"Roy, when you start one of your boards, you have your frame work that the design is built around, you engineered it before doing any thing else.
The blank is the canvas to start with, before doing anything else, I site the blank looking for any flaws in the rocker and deck lines, these are the first steps I take to engineer a shape, I go to the flaws and straighten them out and when I have two rail line curves that match, I can go on to skinning the deck.
The bottom gets the most "shaping" done to it, I bring it down to thickness first, next is thinning and rockering the tail, I move on to the nose, thin and rocker it. Each particular design has it's own thickness and rocker that is shaped for it.
I now have a blank that is to the profile I want, I drop the nose, tail and center widths on the bottom, connect the dots with the desired template and saw it out.
With the blank bottom up and laying flat, I use the planer to clean up to the outline, leaving the last foot to Surform and and doing a final looksee for any places in the outline that are not what I am after. The planer will never lie, it will plow through bumps and skip right past flat spots, but the trusty Surform can and will clean right up to the pencil line on the crookedest of outlines.
Once the outline is done, I flip the blank back over and recheck the deck lines now that it is templated, if there is a problem, I fix it now, waiting til later only causes problems in the shaping later on.
The shape has a center profile, but now I am after the bottom rail line, every blank has it's own special flaws, the opposite side of the hinge side is always thicker, I go to the thinner of the two rails, I shape a rail line profile that will blend into the center line. I caliper the thinner side and transfer those measurements to the opposite side, then shape to those dims., now the bottom is trued up nose to tail and right to left.
I always do my bottom rail bands first, get them right, feather in the rest of the planer work onto the bottom and go to the deck, repeat the same process and am left with about a half inch of an untouched bit of the original outline, this will remain until the drag of my final screen.
I don't use sanders to "finish" shape, the planer work is clean enough to have to minimally sand, with a sheet of nicely broken in # 40 grit, from there I can go directly to #120.
The entire process is, extracting the design I want, staying as close to the parameters of that design as possible, with as little forking with it to fix problems that will cause the design to change from it's original intent.
It is engineering from step one until the blank gets it's serial number on it. Taking 2 passes off the top and 2 passes off the bottom and turning rails is NOT an engineered shape, it is turn and burn, haven't got time to do it right, but someone else will do it over and better.
I shape every day, except Sunday, for 50 years now, what I did today, is a stepping stone to do better tomorrow"
http://jimthegenius.blogspot.co.nz/

Making the Hotkurl part 6

2013-04-04T09:35:00.001+13:00

With the plan shape faired the first rail facets are being shaped, weight is currently 23 pounds @ 10'5" by 27" by 2"

Making the Hotkurl part 5

2013-03-24T17:06:00.001+13:00

Here's the third panel laminated in place, ready for the fourth of five panels:

Paulownia flour and epoxy mix applied:

The fourth panel being laid into position:

Making the Hotkurl wooden surfboard part 4

2013-03-22T20:57:00.000+13:00

The latest phase in the making of the 10'5" hollow paulownia 'Hotkurl' pin tailed surfboard.
Here the first two layers ( deck and first frame panel) are laid on the rocker jig so that the position of the frames and blocking can be marked for gluing:

Roy Stuart surfboards 'Hotkurl'

'Hotkurl' wooden surfboard lamination stage 1

Roy Stuart surfboards: preparation for lamination over rocker jig

Recycled nylon cloth is cut to fit the interior of the deck,this will strengthen it to help support the rider's weight.

Clear Epoxy resin is used to wet out the cloth and then resin mixed with paulownia wood flour is applied to the rail area with a squeegee, and to the frames using a ziplock bag with the corner cut out, like icing a cake.

Bricks are used for a simple low pressure gravity clamping system. The jig has bendy battens so that a 12mm concave is bent into the board. The deck has a corresponding dome.

Red dog in the morning: Manu Bay Raglan

2013-03-12T21:43:00.000+13:00

Manu bay Raglan on the 12-9 Makaha:

Breaking news!

2013-03-11T19:08:00.000+13:00

Ian from San Francisco:

"Well I have been working to much but I have ridden the 13'er a few more times and got some friends together for a test ride today. The surf was a bit funky looking this morning, but the sun came out and the swell picked up after we paddled out.

I had a hard time paddling out because my leash wrapped knotted around the fin.The board would work much better without a leash, but not an option at large OB. After I fixed this I got right out but had to paddle back the 3-4 blocks I had drifted south to meet up with my friends. By then the sun came out with glassy waves that were head1/2 with some 2x overhead sets.

I caught a few good ones and was getting comfortable with the board. When I was sitting on the outside the wave of the day came and I was square-- deep on the A-frame peak. My friend with the Gopro camera was 20' infront of me and lined up just right. I threw the board over the ledge and aired out most of the 13ft board. On bigger boards with some weight to them this works if you can get the nose to hang up in the offshores just enough to set the rail 1/2 way down on a big face. After I landed the drop it felt like cutting butter on the bottom turn and I blew by my friend and made the next two sections. When I hit the innerbar it closed out and I jumped off and got rolled over the falls a few times and bumped the board once. When I came up the board was in pieces. My friends said it was solid double overhead+ but the cameras batteries had died.

I break a lot of boards every year and was very bummed out to see this one go. I am sorry that the guys in Southern California didn't get a chance to ride it in lined up waves. The challenge was about it working in solid surf so that is what I took it out in.

My take on the board is that you have to know how to ride large boards or it is going to take you a while to adjust and figure out how to make it work. The board was a work of art and it must have taken a lot of time and skill to make it. It has a cool flexy ride that I have never felt before and does work well in clean surf. The paddle speed is very good and it connects sections well- twangs through the flat spots. On the drops it goes very fast and feels like the tail planes up out of the water the faster you go. When the wave slows down the tail goes down in the water and you slow back down. The over all effect is that the board self regulates the speed and wants to be slotted all the time.

On one of the big nasty bumpy days at OB I did max out the flex after the whole board was planing out of the water and I hit some bumps. On junky big waves you need a stiffer board. I think this board was very fun to ride and could see a place in my quiver for it.

I am sorry but I think it is beyond repair so the test may be over."