Just in case you're not following gps-speedsurfing, I've relayed the photo. We've been assured it's not a joke, if it is we've been reeled in a long way.

Check it:www.seabreeze.com.au/gallery/gallery.asp?imageid=7842

Hard to believe isn't it????

so turns out all those weekends pollishing those secret weapon 50knt fins would have been better spent with the family, or windsurfing!
hate to say i told u so, but..

"so turns out all those weekends pollishing those secret weapon 50knt fins would have been better spent with the family, or windsurfing!
hate to say i told u so, but.."

You never polished anything in your life.....Any polishing might push that wave fin of yours to .....maybe.....25kts if you stoped doing those flippy things

Here are the other 3 pics. It defies logic really. I do note the worst gouges are on the high pressure side. Low pressure side does not look as bad and I would think that would be the critical one for cavitation. I think I would rather have one without the carnage though.....

i don't get it, do you do this to your fin to make it go faster

As the GPS thread speculates, Martin probably would have gone faster with a clean fin. Or maybe the profile is the most important thing and little dags hangin off would'nt add much drag. Sounds like a good oportunity for some fin wreckin trials, I'm not payin

This is no joke. The pictures you have seen are a special super-cavitating design from the C3 Labs. It is well known that the solid molecules in common beach sand can provide very high lift and dont suffer from cavitation.

Follow the link to see my own new super prototype that should make this approach obsolete and completely revolutionise windsurfing as we know it...

www.seabreeze.com.au/gallery/gallery.asp?imageid=7858

Is that a set of training wheels for Al.

Using a weedy
I thought speedsters would be using upright blade fins.
Any theories anyone??

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BundyBear said...

Using a weedy
I thought speedsters would be using upright blade fins.
Any theories anyone??

Weedies Goooooood


Pointers for *****cats

Would I be right in thinking using a weedy lets you get that much closer to the shore due to it's shallower depth and as a result smoother water?

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sick_em_rex said...

Would I be right in thinking using a weedy lets you get that much closer to the shore due to it's shallower depth and as a result smoother water?

Possibly - that really depends on your location. Some of us are using 20cm fins already - and that is the vertical measurement - so provided you can get started without taking chunks out of your (rather expensive) fins, you dont need to much water while sailing.

The theory is that a swept fin will delay cavitation - or possibly even allow some parts of the foil to cavitate, while the remaining part doesn't (as opposed to the whole fin cavitating over its whole length).

However there are practical issues with building a low-flex fin that is highly raked - often resulting in some flex for the increased rake. Some people suggest that super-stiff is better (faster), while others consider some flex makes for more control (faster).

I am lucky enough to have used Mal's fins (TM45V7, TM50 - both in carbon) and the KA / Chris Lockwood fins (G10). Mal's designs are quite vertical as opposed to the KA's, ie: 13 deg vs I think 30 deg.

Aside: they both felt good - but for different reasons - both fast off the wind - and I'm not that good of a sailor to give a pro/con. Upwind is where I noticed that the KA's bite really well in chop thus tending to avoid spinout, compared to the TM's where they produced more lift so I didn't need to point as hard.

I was thinking more along the lines of aircraft wings, A straight one will give you more lift but also more drag at speed
while a swept one becomes more efficient at speed but gives you less lift when going slower

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sick_em_rex said...

Would I be right in thinking using a weedy lets you get that much closer to the shore due to it's shallower depth and as a result smoother water?

The reason we are stuck with these over here (Perth) is exactly as the name indicates due to heavy growth in river, seaweed at some of the beaches (Pinnaroo) and massive growth down at the crab kickers favourite spot, Hardies run.
We sort of, have become used too them now

Like i said in another thread "the gear don't make the sailor"

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mineral1 said...

sick_em_rex said...

Would I be right in thinking using a weedy lets you get that much closer to the shore due to it's shallower depth and as a result smoother water?

The reason we are stuck with these over here (Perth) is exactly as the name indicates due to heavy growth in river, seaweed at some of the beaches (Pinnaroo) and massive growth down at the crab kickers favourite spot, Hardies run.
We sort of, have become used too them now

I was thinking more in Martin Van Meurs case Mineral. I realise you guys are stuck using them as a result of where you're sailing. The place where Martin sailed is tidal and so I wasn't sure that that was having an impact on the gear being used. From pictures I've seen of the Ray it doesn't look like a weed kind of area but it does look shallow, hence why he managed to scrape his fin up so badly. In saying that though it could very well be all down to what Mathew said re design.

The Time machine fins are more upright and designed to give very high lift and very low drag at reasonably tight angles. Some of Mal Wrights performances at less than 120 degrees in very moderate winds have been quite sensational!! The fins are thicker foiled than the X series C3 and very much stiffer. They need to be very stiff because of their upright plan form. The X C3's that I have seen are quite thin in comparison and by all accounts perform best very broad to the wind where the load on the fin is less and the thin low drag section works best. It has been suggested that the high rake angle shape is not as disadvantaged by not being super stiff (harder to get from a thin foil) as a more upright fin is.
The drag bucket on the TM45 v7 fins is very deep so they also work very well at low loads broad off the wind.
The TM50 development fins are quite a bit thinner but still raked upright at about 12 degrees. The challenge with them has been to make them stiff enough. Some early test fins were not and it was immediately obvious. The latest ones are super stiff, feel superb and are aimed at ultimate 50+ knots conditions on a broad course.
The KA - Lockwood fins have a thicker foil and are quite stiff. They can take high loads and still go very fast well into the mid 40's and Chris has gone 48+ on a broad course. To me they don't feel quite as slippery as the TM45 fins on a tight course but are very stable and secure. The rake seems to make them very user friendly and give them a very wide usability range.
All of these fins are undoubtedly top notch speed fins with more performance potential than most of us can tap into most of the time. All have been proven capable of exceptional speeds. To go faster seems mostly to boil down to human factors and getting the ideal conditions.

Andrew, Chris' foils are a lower aspect ratio than Mal's. I have been running both planforms through Xfoil with the same section (mine, but I bet it's similar to Chris & Mal's as we are all heading in the same direction using the same tools... though I think Mal has been going for more asymmetry). With the higher aspect ratio Mal's work better at higher angles of attack (tight square courses) because of lower induced drag... Chris' work better at low angle ( broad courses) due the larger chord giving higher Reynold numbers. So I guess it's the old horses for courses thing.

Yeah....what he said

Ya gotta understand the physics/mechanics and try & apply it to the practical...

which is where all the variables (often un-quantifiable) want to enter the equation ....

it's a challenge