Imax1 said..
Interesting……..
Id love a go.

There are certainly lots of creative and excellent shapers in Australia

Peter Nitschke has experimented with channel step boards since the 80's. I've sailed a few of them and owned a couple for several years from formula down to speed. You may find them used in Qld . Slightly different to Bruce's

I tested the board in the 2nd last photo and owned the board in the last photo.. Peter also built me a super short slalom board around 220x70 with channel step that I asked him to do.

Super photo. Great to know this stuff was done before. I wonder why the design didn't keep going?

Ostracism was created to stop people becoming tyrants? Maybe this board style has always been a tyrant.

John340 said..

Gestalt said..
As humans we tend to ostracise things that are different.

Or the innovation did not prove to be an advantage in competition

Yep. And that was my experience with step hulls and they didn’t turn particularly well either. The one I have is fun to run for something different but it’s not faster or smoother than my current boards. Well done for having a crack at revisiting an old idea

There should be info on the boards here.
I’d not made a website before but got a little possessed and popped this out.
jimswindsurfing.com/pages/mckee-project

Speaking specifically about peters boards.. Not everything is built for competition. Some things are an exploration of alternative ideas.. testing the limits..steps forward come from trialling new ideas.. but do not assume that elements of peters channel step board didn’t make their way into commercial boards.

for me personally i think the idea works well. Especially on wider bigger volume boards.. i wasn’t the biggest fan on smaller speed boards but others will disagree. i’ve not had any issues turning the boards i owned and found the accentuated v on them made them very smooth in chop..the step also has a similar effect as cutouts in that the reduced planning area effects lift so when fully lit the boards sits well in the water.

the 2 downsides for me were the boards are slower to plane and if the v is not done properly the fin can spinout. Bruces boards have s much longer area behind the step so probably are less prone to fin cavitation.

I really enjoyed watching your video Tom. Good music. Budgie looks like a wicked spot. And good history lesson. I bet they truck up wind.

Flex2 said..
Just got my hands on a couple of boards via Mobz at Jim's windsurfing. We're not getting much wind here in WA at present but this a video on first few runs on the Morph board. Will do further video once we get some wind and hopefully try the Warby.

Interesting test..Keen to see more.

Excellent video. Very interesting.

Regarding fin cavitation in the video. To me, that would be expected for this design, if I understand it correctly. The back of the board is designed to be out of the water right ?

I don't know the purpose of these boards, probably just to play around, but more than an evolution they seem a curiosity. They will never perform like a modern board

decrepit said..
I don't think in this vid they were going fast enough to get up on the super cavitating foil, but that turbulence looks more like ventilation to me, there's lots of air bubbles, below water level

I think I've described the wrong effect. When you get a knife, and slash it quickly through the top of the water - that effect. Like there is a pressure difference between the surface air and the water, and the air gets sucked along the trailing edge of the fin - I think ?. I'm not a Mechanical Engineer.

jn1 said..
I think I've described the wrong effect. When you get a knife, and slash it quickly through the top of the water - that effect. Like there is a pressure difference between the surface air and the water, and the air gets sucked along the trailing edge of the fin - I think ?. I'm not a Mechanical Engineer.

Dragging air into a water cavity, is called super-ventilation.

The easiest example to understand, is the super-ventilating propeller design for speed boats -> it entrains atmospheric air into the flow, so as to stabilise the boundary/interface, typically resulting in lower drag for that surface interaction.


Under some circumstances, super-ventilation can lead to a super-cavitation mode of operation. It is an interesting area of research. In both cases there is a high-drag effect at low speed, which makes them unsuitable for power-limited craft such as windsurfing .... at least at this point in time -> maybe an unconventional board shape could allow using these modes of foil operation.

sick_em_rex said..
Not sure how you can say that without ever trying them. Maybe do some research on the idea before you give out your opinuion. And why do you think it is not a modern board? They were made literally this year using advanced construction processes. It wasn't some old board/s pulled out of moth balls. Bruce designed one of the biggest selling Australia funboards of the 80's, that being the Bombora Capricorn.I think he knows what he is doing. I actually think you owe the guy an apology with your comment. If people didn't experiment with different designs then we would all still be riding Windsurfers.

If we do some research about the physics of planing hulls, then we see that they’ve been well and truly explained since before David Savitsky did his work. We then know that the physics of planing hulls show that a short, wide area of contact with the water is more efficient in terms of lift for drag, because drag drops by the square as width increases. We can see pretty easily that even if the board was only planing on the tiny patches at the back of each “sponson”, then in just about any chop the waves will be hitting the “tunnel” which will increase wetted surface friction.

If we do some research we also find out when guys like Jim Drake created the shift from skinny Capricorn-style narrow boards to the wide style boards that have dominated windsurfer design for the past few decades, it was because they had done the research and knew that for planing, a wide aspect ratio planing surface is generally far more efficient. So if we do our research on the idea, we can see very good reasons to say that it probably won’t work any better than when it was tried about 45 years ago,

Paducah said..

Chris 249 said..
If we do some research about the physics of planing hulls, then we see that they’ve been well and truly explained since before David Savitsky did his work. We then know that the physics of planing hulls show that a short, wide area of contact with the water is more efficient in terms of lift for drag, because drag drops by the square as width increases. We can see pretty easily that even if the board was only planing on the tiny patches at the back of each “sponson”, then in just about any chop the waves will be hitting the “tunnel” which will increase wetted surface friction.

If we do some research we also find out when guys like Jim Drake created the shift from skinny Capricorn-style narrow boards to the wide style boards that have dominated windsurfer design for the past few decades, it was because they had done the research and knew that for planing, a wide aspect ratio planing surface is generally far more efficient. So if we do our research on the idea, we can see very good reasons to say that it probably won’t work any better than when it was tried about 45 years ago,

Lindsay Lord (1930s 1940s)
books.google.com/books/about/Naval_architecture_of_planing_hulls.html?id=f_wZAAAAIAAJ

His research suggested to a 2.5 to 1 length/width ratio similar to what we would eventually see in formula windsurfing boards

which led to Bob Simmons (1950s)
www.surfline.com/surf-news/bob-simmons/89860

Lords book is a great read. There is also lots online from bob simmons research. If you are into this stuff this is ground zero. The shapers handbook is another excellent resource. Especially if your aim is to design boards based on functional choices as opposed to doing things cause they look good.