Introduction
The final entry in a four page design feature titled Australian Unorthodox : The Religion of Oz Design.
Other contributors are Dougall Walker, Terry Fitzgerald, and Rod Hocker, see below.

In a long article, Geoff McCoy details his Basic board, a rounded pintail with the wide point forward, and Cheyne's board, harder to ride but capable of higher performance levels.
Cheyne was Cheyne Horan, McCoy Surfboard's top team rider, and this design moved the wide-point back to the middle of the board, the first step in the development of what became known as the No-Nose design, later becoming the single fin Lazor Zap before evolving into the three-fin Tri Zap and the soft-nosed Nugget.

Michael Rae, of Outer Island Surfboards, writes of his concave bottom design with George Greenough inspired flex-tails.

At Byrne Surfboards, Phil Byrne added a deep vee with channels, derived from clinker-planked boats,  to the contemporary twin-fin design of Mark Richards.
An attempt to convert sideway drift into forward thrust, the design was quickly eclipsed by Simon Anderson's Thruster.
Interestingly, while Byrne writes that ardent single fin rider, Tom Carroll has been tempted by the Clinker twin-fin, in the same edition Dougall Walker lists Tom as an early convert to the three-fin Thruster.

 In an interview with Nick Carroll, Newcastle goofy-footer Col Smith, recalls the development of Concave-Channel bottoms in association with Jim Pollard at Shane Surfboards.
Col Smith (Newcastle) is not to be confused with North Narrabeen's Col Smith, another hot goofy-footer who manufactured Morning Star Surfboards.

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Page 18

The best way for me to explain what we are doing is to give you two examples of our range. I will explain the various functions of each extreme and naturally in between takes care of itself. The basic board: This term applies to a clean outline board, smooth bottom — in other words no real prominent reaction points to give the board definite performance advantages and disadvantages. This design is for smooth all-round performance. Usually surfboards react as they look, smooth soft lines and curves give smooth soft even performance. As the board takes on more prominent design features, it gives a quicker, harsher reaction. What I am saying is, the relationship between the board's capabilities and the surfer's ability is very important. It's to no one's advantage if your ability is for a 'Porsche' and you are trying to ride a 'Formula One Turbo'. The majority of surfers these days are riding boards that are over designed for them. They have too high a performance level for the surfers' abilities. This applies to a very high percentage of designs available right now. It's OK to cut away the outline of the board, gouge out grooves in the bottom and put lumps and bumps generally throughout the board. The only trouble is they all change the performance of the board to varying degrees. An important thing to remember is that as boards decrease in size — not only length, but plan shape area and thickness — they are become lighter. Definitely not stronger though. Keeping this in mind you could imagine taking two identical surfboards, except for the actual weight of the boards — one is one pound lighter than the other. The lighter board will have a quicker reaction time than the heavy board — it's obvious. The board would even have a natural flotation point higher than the heavy board, less displacement... more manoeuvrability.

The less water you have to displace the quicker the reaction from manoeuvre to manoeuvre.
So what I am saying is, not only have boards been becoming smaller and lighter, they have been undergoing radical design changes in general.
Some of them are good — most are bad.
It is much harder for surfers who are starting out to ride a board these days than it was to catch a wave and stand up in the old log days.
The balance and reflexes of modern surfers are much more critical because the surfboards have become much more reactive to the body and wave movements.
If you take this to the extreme, and in many cases it is, you have a situation where the boards are just not going to work because the levels of ability are so far apart.
Until you become a competent surfer, for example B grade level in club contests, you probably don't need a radical surfboard.
If you consider all the points I have raised you will probably realise the easier the board is to ride, the better you ride it.
As I say it's relevant to surfers' abilities.
What's easy for Cheyne to ride is not easy for other surfers to ride.
So for the basic board, as we will call it, we have a full even planshape, curved nose and tail, nice even entry curve feeding onto a large fiat planing area that releases into a dome curve through the tail.
I will explain why the board contains these design ingredients.
A full even outline pin nose and tail, combined with the slight curves across the bottom of the board both ends and a large flat planing area in the middle, gives excellent stability and speed.
The slight curve across the board in the nose and tail gives the board sensitivity both ends with stability in the middle (flat).
The design concept I am applying to my boards these days is the same one I have been using for the past five years.
It's simple, effective, and has no limitations to how it can be varied for a whole range of performance levels.
Once you realise what you are trying to do on a wave, the next thing is to build a surfboard that's up to it.
Plan shape: If you take the full pintail, give it the design features I have already mentioned and combine it with these others, you can draw your own conclusions about performance.
Smooth even bottom curve along the stringer.
Even thickness through the middle and back of board, if you are going to stand all over the board you should have it support you all over.
The rails are shaped with positive entry, neutral through centre and tail except for the last six inches, then positive again.
The positive entry gives the rail even feed at all times: positive entry means a steeper rail with a lower harder edge under.
The steepness does not let the board bog or slice but rather it sucks and holds on the fullness — that's why the edge is underneath to release, or sheer, the water off the rail to stop it sucking or holding too much.
If this is done correctly, you end up with a rail that will feed automatically, wherever it makes contact with the water.
Setting up your water flow through middle and tail.
The rail through the middle has a full curve off the deck blending around to a low full curve under this is the neutral area of the rail line where all manoeuvres start from.
The rail in the tail area is like the nose, it needs to be positive to maintain control at all times.
The rail twists down off the deck through the last one-third of the board.
This helps the water flow work with the bottom curve in the last one-third of the board.
In this area the bottom of the board takes on the appearance of a dome or the top of a sphere.
This soft gentle curve across and along the bottom make the board have a reaction like a ball joint.
For example, if you have a flat bottom the board tends to surf flat.
If you have a V the board has two flat surfaces to work on with a change over point in the middle, the top of the V.
So we put a dome in the tail.
This gives the board a much greater range of axes to turn off: it allows the board to turn in and under the lip, it gives better control in the tube because a dome releases evenly and constantly right across the bottom; smooth curves, smooth performance.
The advantages of a dome are obvious.
Flat bottom — flat performance, V bottom — bump in the middle with two flats, dome — soft even curve for 180° across the bottom.
Because we use this method in our designs we are now able to increase tail area in the planshape.
This gives the board more resistance when you push down in a turn.
That means more squirt throughout the whole turn.
The reason for this is the combination of bottom, rail, planshape and thickness to obtain the necessary sucking effect that is required to hold down the increased area.
For example, if you take a teaspoon and hold it under a running tape, convex surface against the water flow, it will want to pull into the flow of water.
The same principle applies to the tail area of our designs.

They actually suck down and hold, and at the same time you stilt have the curve (ball joint) to turn on at any time you are ready.
Once again, because it's curved you get instant response and reaction at all times.
Now that's hard to beat.

These design features that I have mentioned in relation to the basic board apply equally to our top of the line, high performance board that Cheyne is now riding.
The same ingredients of a design theory apply, except they are much more prominent, and obvious at a glance.
To my mind the essence of good design is in the subtle blending of all the ingredients.
This becomes a problem, when, for example, the basic board, say 5'10" x 20", has 1'' tail lift throughout the last 18".
Cheyne's board has 2 1/2" in the last 12".
Nose lift on the basic board is 5 1/2".
Cheyne's board has 8".

Because I am putting more curve in the bottom (length and width), it is increasingly more difficult to flow all the curves together. So, for now at least, Cheyne's board has prominent design features that as I mentioned before give it more obvious performance characteristics, making it harder to ride but more capable of higher performance levels. It's like the 'Porsche' and the 'Formula One Turbo'. The Porsche is a refined version of a race car, or a high performance road car. It has had ail the corners rounded out to cater for the less skilled driver. Our basic board has been designed with the same appeal. The Formula One Turbo is a full brute race car. Hard to tune, difficult to control, but in the right hands it is capable of awesome performance levels. Cheyne's board is in the same performance bracket. Both boards I have described perform the functions that are asked of them... it's vital that the surfer chooses the right one! Geoff McCoy Photo Peter Simons

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Page 19

From the early seventies, this design has been refined and tested in search of speed and manoeuvrability, namely, control in a versatile surf­board. It favours the juice, but can function in the slop, and a great deal of variation can be employed within the design to accommodate the needs of various surfers and waves. The original concave design in 1970 came from Glynn Ritchie, David Chidgey and myself. The chines were added later as a safety factor and to reduce rail catch. The tucked-in nose and the flexible tail were introduced in about 1975. The flex, of course, inspired by George Greenough. Basically the design employs an even curve planshape, widest point slightly forward of centre, and a variety of tailshapes (I favour pintails and roundtails).

The concave bottom reduces push from the bottom curve, so extra curve can be used to give tight arcs and rail turns.
Gathering air and water, the concave tends to enclose and channel the water flow out towards the tail.
This creates lift and the board rises, giving less wetted surface, extra speed and thrust, and more manoeuvrability.
The nose entry is pulled in to reduce resistance in a yacht-like curve, chined softly underneath for easy entry and looseness.
It also gives control for turning when on the front, trimming back in the tube.

The flextail uses the same planshape as normal, but makes the tail section bend and flex into a tighter curve, like a fin.
This gives tighter arcs when turning and a horizontal thrust out of turns, in unison with the fin's vertical thrust.

The latest development refinement is a combination of a concave feeding to a tail vee - directing waterflow to one side or the other also works well, especially for hot dog boards, because of easy planing in small surf.
However, the boards are in their element in the long, clean walled tubes of Indonesia and the North Coast.

Mitchell Rae

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Across the bottom are a series ot straight planing edges that move outwards from the boat's centre as an exaggerated Vee, overlapping each other (diagram A). The number of Vs depends on the number of clinkers, the clinkers being formed by laying one plank over another. With surfboards, this effect is shaped into the foam (a nightmare for the production team in construction of these boards). The main distinctive feature is that there are no curved areas but all straights. The bottom is designed to reduce sideway slide — the edges of the clinkers give the bottom of the board more bite into the wave face. By doing this the board is converting energy lost by sideway drift into forward thrust. Because of this first basic function, the bottom design is particularly well suited to twin fins.

Another feature when looking at the design is that the low spots, or shallows of the clinkers, act as quick release areas for the water along the bottom Itself.
It is for this reason that the first shallow does not follow through the tail of the board but stops short, acting as a 'straighter' bottom curve between the centre of the board and the tail.
This is shown in diagram B.

The outside clinkers, because of the curved planshape, run out the side (usually at a wing) and as well as their clinker effect they act to give a squarish rail in the tail for more skate in the board — but at the same time the clinker acts to thin the tail and to retain sensitivity of the surfboard.
This same principle was clear in the bonza design some years ago and was partly responsible for the success of it.
These two features together result in a very fast, responsive surfboard, particularly when applied to twin fins.

It was these characteristics that tempted two ardent single fin riders, Tom Carroll and Chris Byrne, onto the boards.
Both have found the boards to be unbelievable in tube-riding, an area that twin fins were notoriously bad — with the ciinkers increasing the holding power of the board on steep faces.
Another increase in performance comes from the board's sheer speed and the ease in which it comes off the top in snap-backs, the exit of the outside clinker at the back rail acts like a lowered wing for extra bite.

One characteristic I found great is when coming from behind white-water.
The clinkers can be used for extra bite to pull the board along without putting it up on its rail fully, which often can take the board out of trim and result in loss of speed.

One thing that should be said is that these boards are very loose and sensitive.
Some surfers who have more of a cruisy-type style might find them over-responsive and just too loose and radical to ride.
As with all surfboards, some designs suit some surfers and not others and there is no one design that is perfect for everyone.

How did you get involved with channels at first?
Well, originally it came from a Queen­sland surfer up at Caloundra, Jim Pollard.
I experimented with him — he actually had a surfer called Steve Butterworth who was surfing with him at the time and he actually first put me onto them and then we took it from there and we worked with them, for like, three years, four years.

That was Fluid Foils?
Yeah, that was Fluid Foils down at Shane's.
Actually Shane came into the thing a little bit later.
Me and Jim had been working together in New­castle and up the coast for quite a while then we moved to Shane's because, obviously because of the factory and the facilities there.

When was that about?
Ahh, two years ago, three years ago.
74 was the big year I had with Shane and it was when I first took the channels to the Islands.
They worked really good and I won the Trials.

Right. What did you think at first when you saw Jim was doing the channels?
Did you just flash on it straight away and say this is what I want or...?
Nah, I looked at 'em.
I was very sceptical.
I surfed a fair few first — I used to find with Jim's boards that I would get one in every three that had the magic feel about it — the others used to be a bit funny at times.

What is their performance trip? What do they do?
When I was working with Jim and Shane the channels were a lot more rolled and softer.
So what we did we changed the whole thing one day, after leaving Shane's I went out by myself and I was just experimenting with all sizes and because I do a lot of fishing, I've seen the fishing boat designs — straight off the clipper hull design, virtually.
Um, it was a matter of putting them in a different way so that you get planing area.
Instead of having rolls and flats on the bottoms we like to use concaves just under, low flats so the boards work super fast — they actually get up on top of the water.
And where you get a lot of friction off other boards it is when you get 'em up on top of the water they don't maintain — they sort of get too loose at high speed.
But with the channels we're finding that all the extra grip power seems to be just that — the channels are enough to hold the board flat on the face while you get plenty of speed.

So you've more or less developed from the rolled, curved channel to the clinker.
To the clinker, yep.
We're currently doing them maybe ah, they'd be nearly half inch deep.
So we've come a long way — we're putting them definitely right into the boards at the moment, really deep.
We're using a little more tail curve than most of the other guys — it lets you surf along the board and you can be a lot looser, you know.
You can surf much bigger waves.

Do you change the number of chan­nels according to how big the board is, or is there anything...
I have experimented with the chan­nels.
We find urn, I use eight channels myself, we started with the sixes and originally we started with fours — but it's only a natural progression, you can't really go backwards over your own tracks.
All our stock boards are sixes, unless we're ordered eights.
And the eights — ah, I find they get a little looser as you put more in, and maybe a little bit quicker from rail to rail.
What we try to do also with the six channels is we make them extra deep, which gives you nearly the same feel as the eight, but the eight just fills the bottom right up on the board.

They seem to go more or less unreal in Hawaii too, which is sort of a change from most other innovations over the last couple of years, such as twin fins.
Yeah.

Do you think that's a big advantage?
Well it is a big advantage because what we're having at the moment, that I can see anyway, in the professional thing is you've got guys who are surfing twin fins, they are having to change up to a single when they're coming into bigger surf.
Now when they're running into this bigger surf they're having all sorts of problems — they don't know what's happening — because they're so far apart, twin fins and single fins are far apart.
All we've done is add the channels to the boards, and it's virtually the same basic board that you've always rid­den.
Any guy who's ordering one — if they like round pintails or something in that range, that's exactly what they've been riding and we're just adding to the actual board which they've been riding.
So, it comes back to the old basic, which has always been the best, but all we're doing is adding to it and making it better.
We're improving on a very old design.

You got any ideas about how much further you want to go with channels in the future?
Well seriously, Nick, when I start looking at the bottom curves and concave aspects, water flow aspects —  there's so many different ways I can change my channels right now to improve them slightly this way or slightly that way.
Basically I've got what I want at the moment.
I've had a lot of trouble over the last few years with short, small wave boards.
Nat­urally the twin fin comes into its own.
But I really feel this year that I'm starting to get to the stage where I'm really finding out about what short boards do.
I'm riding a 6-footer which is unusual for me, very short, you know — using a hard edge under the rail is starting to work really good.

Have you had any thoughts about the more unusual developments of the past few months, Simon's Thruster thing, for instance.
Have you thought of any developments along that line, just within the channel?
I'm always thinking about that type of thing.
I feel they're the ultimate thing to put in twin fins, although I don't know anything about twin fins.
I feel they would have to be a definite advantage to getting a lot more drive out of the actual board.
I think it would promote the speed a lot more and give a lot more draw.
The tri fin is another classic example.
You can suit your channels to sit your fins on the high edges of each channel wherever you want to.
As I say you can draw channels up in a lot of different ways —  there are so many aspects.
You can do it in a very simple, basic thing or you can do it to suit whatever board you're surfing — be it tri fin, twin fin or whatever.

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Tracks May 1981  Number 128. Australian Unorthodox : The Religion of Oz Design Dougal Walker : The Tri-Fin - Did God Mean It To Be? Terry Fiztgerald : Drifta III Rod Hocker : Conaves and Fin Boxes. Geoff McCoy: Design Mitchell Rae: Tails Phil Byrne: Clinker Bottoms Col Smith: Conaves

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