Beyond the Rectangle. Surfmats.

[ULTIMATS]

Great post Matticus ^^^, there's a bit of a bashing crew at Sways that pick on some of the newbs and its not pleasant to watch. I'm only interested in new stuff so I don't read the threads about the 60's nose riders.
This is an interesting thread about mats because it flies in the face of accepted knowledge that mats in motion are a floppy bag. They're not 'surf o plane' hard but some mat riders just can't accept a new interpretation.
Ive had one guy say air pressure on a mat isn't relevant, but pressure is the core element that controls the mats pliability and ability to change... Some people just don't want to know....
A thinner mats a brain teaser too, if a mat has say a 30 litre volume, but its never fully inflated and only filled with 10 litres, then then why not just make a mat with a 15 litre volume ?
I like all your ideas, thats how I start inventing, come up with a few new ideas and then work out which one is the best to try and then go for it.
Feel free to heap abuse on me anytime I say something new !
Alakaboo, you're going deep into the physics there, but I agree its all interconnected, change one element and the others change too.

[MrMik]

...
... Mats have a poor ability to grip a wave of any size especially with their 5 inch round rails and youtube videos show riders on decent waves using their inside arms/hands\fins to provide resistance and maintain position on a wave.
Other surfcraft use hard surfaces and sharp rails to provide speed and grip so there's room for a mat- hybrid that utilises the unique high speed acceleeration of a soft hull and high bouyancy mat and add the control of rails.

My understanding is that hard rails release and soft rails hang on to the water, give better hold on a wave face.

[ULTIMATS]

Matticus, its not expensive to make mats but its an exacting task.
MrMik, that's my belief on rail design too but I think there's limit.
And that limit is where certain ideas or shapes will work but beyond that limilt they don't work as well.



There's only so far water is going to wrap up a rail and against gravity too.
The bigger the rail the slower the curve and water will have a finite ability to climb an arc thats a slow curve and not curved enough to hold the water.
Of course the water flow isnt perpendicular to the curve of the rail at all but it segways nicely into my idea about making a thinner mat.

There's still going to be some drag associated with the round rails and tail of a mat but because the curves are so big the effect will be less than on a fat 2" rail.... iMHO of course..

[fins]

interesting stuff ,

keep it coming !


then , a standup version , down the track ??


last question ....

how thick is the ply ?

cheers !

ben , the 'newbie' [I think my post count is going backwards ? ..... who cares though haaaaa ]

[ULTIMATS]

Ben,
The ply is 5mm 3 ply, 3 layers with 10 oz glass in between but the next one will have a plastic frame.
Ive never thought of building a standup version, that's good forward thinking !

Now Ive got another thing to build !!!

[ULTIMATS]

Along with the flexible frame I'm putting in FCS plugs to see how a mat reacts to the stability and grip of small side fins..





I've got a selection of small area fins to try...



More likely that the white high aspect fins will provide the short instant of hold. I'm not looking for a fin with long hold, just a instantaneous moment of redirection. Mats have little hold on the water and a 'grabby' fin will slow it down.
The fin needs to be as light and fast as the mat is.



I'll try a few different fins and thanks to Ben Chipper for making a few for me.

[kayu]

A mat and a surfboard work on two totally different principals , regarding drag..mats are neumatic craft , with very little drag henceforth the ability to surf at such high speeds.....the downside is lack of directional control.

[ULTIMATS]

Kayu, thats my cunning plan !!
to take the speedy yet quite directionless mat
and add just that little bit of control.
What Im not sure of is what sort of fin would best suit,, a longer base will give more drive but it will also sap the top speed of the mat.
Im thinking something like those FCS dagger fins in the pics above , shorter base but with a bit of depth and rake so the turns are smooth as the mat rolls.

[alakaboo]

I can't really figure out why, but something tells me that really heavily canted bonzer-type side fins would be good. So that you can keep as little of the mat in the wave face as possible and still get some hold.

[ULTIMATS]

I put the plugs in at 6 degrees for max cant and I'm thinking that a thinner fin with a flat foil will be fastest, I'm not looking for any lift effect from the foil, I'm sure there's enough control with a 'flat plate' style of fin.
If the high aspect fins don't work I'm definitely going to try the Bonzer style canards that you mentioned Alakaboo.
For something like this it will need a distinctive fin to enhance the mats subtlety.

[kayu]

I think as soon as you introduce any rigidity at all , it would detract from the unique mat performance. I remember riding the old blow-up rubber ones as a kid.....the ones with the vulcanised rubber fins , and they would slide sideways when pushed down the wave very quickly , without losing any noticeable forward speed. There's plenty of online footage proving that a mat can make just about any wave , even in huge surf........I can only assume that its the soft , big radius rails which pull into the wave , while still remaining extremely low drag because of the soft forgiving nature of being air-filled......it's easy to get a headache thinking about it.....they are the ultimate low COG surf vehicle.

[ULTIMATS]

The internal frame is only 1.5 in wide and the theory is that when the mats flat or angled down the wave, the flexible hull will allow it to accelerate like a mat does.
But when you hit a bottom turn the flexible frame around the outside will provide enough resistance to redirect that speed when you put the mat on its rail.
Mats also drop off steep faces so the semi solid rail should hold in for tubes and steep walls and sections.
You're a professional wood guy Kayu, what's more rigid..a single piece of wood or a laminate ? Or does it depend on how you glue the laminate ?

[kayu]

You're a professional wood guy Kayu, what's more rigid..a single piece of wood or a laminate ? Or does it depend on how you glue the laminate ?

How longs a piece of string ?.......different woods/different performance/different tensile properties effecting flex/rigidity.....Wood is easy enough to make flexible in the longitudinal , but hard in the transverse......check out the flexible battens used in high performance racing sails or the framework that gives the shape to hang-gliders.............or even the fiber rods that hold a dome tent together in gale force winds....Wood laminates (or other composite materials) are used to mold into a specific form , and can be engineered to be rigid or flexible , whereas mats are inflated and have little resistance to taking any shape on the wave....Any introduction of rigidity will increase the resistance.

[ULTIMATS]

The laminated frame is only 10 mm thick so I put a close cell foam layer on top of the frame.
The foam creates a thicker, functional rail,
a better rail shape to hold onto,
a softer top to lay on,
and I angled the top of the foam so it will mimic the curve of the inflated deck..

[ULTIMATS]

Putting the I-beams in.

[otway1949]

There is one thing to be said about low inflation it makes the mat easier to get out to the surf zone, a fully inflated mat trying to duckdive or the matticus equivalent without or even with handles is a nightmare. try submerging an inflated inner tube..
I love my mats Krypt and Fourthgear flyer, but in sizeable surf I get really worked unless there is a clear channel out around the break.
There is also the boing factor hit chop at speed and you are airborne Often blowing a chamber on impact.

Look forward to seeing an Ultimat in action better yet trying one

[ULTIMATS]

Thanks Otway 1949, Ive made it only 2 inches thick so it should float most people but it doesn't need to be totally full to maintain its shape. The frame should give it total control like a bodyboard to turn and duck dive but the inflatable body should be soft to lay on and have that pliable hull to run over the ripples at full speed.
I wouldn't do the frame in wood ply again, next time it will be in a laminated plastic and I will put some nose rocker in too.
I'll give it a go with and without fins and try all the variations I have at hand and then make another. If you're in Sydney I'm happy to hand it over after testing ?

[ULTIMATS]

Putting in the I beams ..





And measuring the top sheet so the I beams line up.