That will be very interesting to know what is maximum speed achieved among our team members depending on the board size.
For example if we divide our results into similar categories
=> 150 L
130 to 150 L
120-130 L
100-120L
80-100
60-80
50-60
>50 L
?
For myself as a beginner speed sailor I found very hard to push my 118L slalom board much above 30 knots.
I will possibly can have few knots more in right condition but in order to have significantly better result I need to use much smaller board.
So that will be interesting to know how much people been able to pull off their boards in relation to size (another option could be attempt to categorize by width or fin size).
So for illustration my result is
JP 118L (8.0, 68 cm, 37,5 fin) -30.5 ktn
slightly more on smaller board before I joined GPSTC.
First of all don't be too hard on yourself, 30.5 on a big board with a big sail is respectable.
Ok, I will kick off. I am 5'11" and 90kg
Category 100-120L: Falcon Slalom 113: 69cm wide, 36cm Meanline Fin, 7.1m KA Race, Course: tight, slightly downwind = 34.68kn 2sec
Category 80-100: Falcon Slalom 99: 63cm wide, 34cm FO Weedy, HSM 7.3m. Course: Choppy downwind = 37.13kn 2sec
Category 60-80L: Falcon Slalom 79: 56cm wide, 25cm Caspar, 5.5m HSM GPS, Course: down wind = 39.22kn 2 sec
I ran the Falcon 113 with the 7.1m at Harrington a month ago on flattish water again, and was having a blast on the big board/smaller sail/fin combo hitting 34.5kn 2sec across/slightly off the breeze, on a very tight course. Then I decided to keep the sail and step down to the Falcon 79 with 30cm Meanline fin just for the exercise to see what the outcome would be, and picked up an extra 2.2kn 2sec on the first run. Board size / and board width obviously makes a big difference Macro, so long as you have enough consistent wind to keep the set up fully powered, and keep the smaller board moving efficiently. There have been times that I have changed up a board size, and kept the same speed and had a whole lot more fun on the 113.
.
Category 130-150
2sec = 30.66
2013 Rocket 145
GPS 6.6
Category 120-130
2sec = 35.57
2008 Futura 122
GPS 6.6
Interesting topic! I am 5'10" and 105kg
The bear-away is the most important thing Macro, deeper you go the faster you go (as long as you are powered up)!
And I am still working on it!
Category 130-150L: 1998 Bic Vivace 149L Raceboard 8.6m Loft race blade 34.09 knots
Category 120-130L: 2005 Starboard 126L S-Type 6.3m Loft Switchblade 36.26 knots
Category 100-120L:2013 Carbon Art 117L SL67 7.3m Loft Switchblade 36.43 knots
Category 80-100L: 2010 Carbon Art 100L 60W Freeride 6.3m Loft Switchblade 38.94knots.
Select to expand quoteMattDowse said..
Interesting topic! I am 5'10" and 105kg
Category 130-150L: 1998 Bic Vivace 149L Raceboard 8.6m Loft race blade 34.09 knots
Category 120-130L: 2005 Starboard 126L S-Type 6.3m Loft Switchblade 36.26 knots
Category 100-120L:2013 Carbon Art 117L SL67 7.3m Loft Switchblade 36.43 knots
Category 80-100L: 2010 Carbon Art 100L 60W Freeride 6.3m Loft Switchblade 38.94knots.
Wow that's impressive. I'd d love to come and trade notes with you on a windy day. I'm exactly 6 foot and 100 Kg (ex-rugby). Pretty much never get 25 knots but manage around 30 in 20 knots on 117 iSonic and recently 33 on 107 on a 20 Knots plus day. I'm really working hard on technique but often find lighter riders focusing on different things. I definitely prefer bigger sail smaller board as my combo but have nothing a a guide. Biggest problem where i sail is running out of water (i.e. shallow and or boat)
I'm 5' 10" and 74kg and I'm a lot slower than you guys above. AJEaster 37 knots plus on a Falcon 99L with a 7.3 and a 34cm fin - Respect! I got splattered with a 5.8m and 32cm fin on the 99 two weeks ago at 32.5 knots and felt the board was just too big and light..
120 - 130L: Fanatic Ray 125L with 36cm and NP H2 6.7m 2 sec' 31.2 knots
80 - 100L: Falcon 99L with 32cm and NP H2 6.7m 2 sec' 33.01 knots
60 - 80L: Exocet 50 with 28cm and KA 5.8m 2 sec' 35.09
Would love some tips on how to improve speed as a lighter rider, other than carrying weights 
Great stuff Eel. We had Byron up from down your way and showed us "a new level". In genersli used to think, big sail all the time and big fin and it was a little counter productive (gybes were a nightmare), I realized that once it got to 25 knots i was on the same gear as everyone else (5.5 etc) , on slalom gear I rig a bit bigger for the broadwater as its gusty but the the fin in particular seemed to make a big difference. Im just learning this GPS stuff so its all give'n take but boy I've enjoyed the challenge of it. I cant wait to get the 107 somewhere where I can have a run of a kilometer or so and get her up to speed rather than a 500m meter "run of terror" surrounded by jetskiis and kites (maybe that's my wish for 2014) 
. All I can say is that every little thing make's a difference boom height (sausage gave a great explanation of this the other day to us), out-haul, mast track position etc..., try it all out one at a time cause it adds to the enjoyment (for me anyway and I'm a complete novice) Guess its just the learning curve again, ...cant wait to learn more
Interesting reading - good idea for topic. I think board width should really be the basis for size categorisation rather than volume:
1. Once planing, board width rather than volume is the key determinant for how much board/water contact there is and therefore how much water-induced friction is holding you back.
2. Starboard (as one example I know) abandon volume as their size measurement once they get down into the speed boards. These are denominated by W49, W44 etc (being width measurements) rather than 113l, 82l etc (being volume measurements).
3. For my own example, I have two identical volume boards of 105l (giver or take 1l). A 76 ish cm wide Starboard Hypersonic and a 65ish wide Fanatic Falcon. The Falcon is easily another 3-4 knots quicker in any situation than the Hypersonic, and I believe this is mainly due to width (although the radically double-concaved bottom on the Hypersonic could arguably also be an influence).
However, for the purposes of an entertaining and informative discussion, and while-ever board volumes generally correlate well to board widths, I can live with a volume-based categorisation!
Eckas.
Select to expand quoteeckas said..
Interesting reading - good idea for topic. I think board width should really be the basis for size categorisation rather than volume:
1. Once planing, board width rather than volume is the key determinant for how much board/water contact there is and therefore how much water-induced friction is holding you back.
2. Starboard (as one example I know) abandon volume as their size measurement once they get down into the speed boards. These are denominated by W49, W44 etc (being width measurements) rather than 113l, 82l etc (being volume measurements).
3. For my own example, I have two identical volume boards of 105l (giver or take 1l). A 76 ish cm wide Starboard Hypersonic and a 65ish wide Fanatic Falcon. The Falcon is easily another 3-4 knots quicker in any situation than the Hypersonic, and I believe this is mainly due to width (although the radically double-concaved bottom on the Hypersonic could arguably also be an influence).
However, for the purposes of an entertaining and informative discussion, and while-ever board volumes generally correlate well to board widths, I can live with a volume-based categorisation!
Eckas.
Agree , to some extent. Above 30 knots we are all in interested in not so much volume but width or wet area that matter.
But there so far is strict correlation between board size and volume so for simplification we could stick clearly to volume ( but still provide addition information about width and FIN SIZE).
If in my scientific anticipation any conclusion could be drawn for future board description could be some sort of:
wet are x fin area x at the speed in knots.
For example: at 30 knots - wet area is 300 cm2, fin area 150 cm2 for standard 80 kg sailor. ( example formula)
As examples above demonstrate there is emerging pattern of smaller boards achieving higher top speeds.
My personal at this moment admiration comes to those that could achieve remarkable results on relatively big gear
In 2012 we did a small competition between a couple of friends who could reach the highest speed and fastest 5x 10 sec average using a 67+ cm. wide board and a 7.5+ sail. At the start of the year the fastest guys where on 36 kn top speed and 34 kn average.
At the end of the year I was the fastest on my JP Slalom VII 68 with C3 Sting II 40 and NP Evo IV 7.8
Max speed 39,1 kn and 37,11 kn 5x 10 avg. The 2 fastest runs where above 38 kn so a 38 kn avg must be possible. The other guys had 36+ averages and 38+ max speed.
We're all 6'1+ and around 100 kg. The spot we use is Strand Horst. In late summer it's dead flat to small chop. I must say we pushed our gear far beyond regular use that year. We sailed the big gear in 20 to 25 kn base wind with gusts over 30 kn. Timing is key, sail upwind as much as possible looking for gusts. Just before a gust start sailing half wind. The moment the gust hits bear of to about 110 slowely increasing the angle to 140+ the further you get into a gust.
www.gps-speedsurfing.com/default.aspx?mnu=forum&forum=2&val=41291
Check no. 1, 2 and 4
As for Formula gear..
www.gps-speedsurfing.com/default.aspx?mnu=user&val=141254&uid=930
Select to expand quoteeckas said..
I'd love to hear some stories about how fast formula gear has been pushed!
gpsteamchallenge.com.au/sailor_session/show?date=2013-11-05&team=99
Did a 39.98 2 second on a my Prototype 70 wide slalom at Sandy Point last November. Cheated a bit as I only had a 28cm Slalom fin in it and a 5.5 kaRace sail. Would have been 25 knots of wind I reckon, could have gone faster with more wind. Guys were running 42,s on their speed gear at the same time so the big board was only a little slower.
I saw Spotti do a 42 peak on his Mistral 137, 82 wide, think he had a 6.2 Koncept may have been a 6.6, had a speed fin in it. Amazing!!! I did a 44+ 2 second in the same gust on a 54 wide speed board.
Peter I think you are on the money re: FIN SIZE - whilst wetted area (and therefore drag) has an effect, the determining factor comes down to fin size i.e. the smaller the fin you can get away with irrespective of board width the better your chances are to increase speed as drag from the fin is the major limiting factor. Of course it takes some talent to use a small fin in a big board but if all you're after is max speeds and don't need early planing or pointing ability then go smaller than normal. Slowboat uses fairly small fins in wide boards but as anyone knows he's a freak.
Select to expand quoteMacroscien said..
>>>>>
Agree , to some extent. Above 30 knots we are all in interested in not so much volume but width or wet area that matter.
But there so far is strict correlation between board size and volume so for simplification we could stick clearly to volume >>>>
when you get to small speed boards there can be a lot of difference between manufacturers for volume/width, eg. slowy's boards seem to have more volume than others for similar width.
And I can't tell you exactly what the volume of my boards are, but I can tell you how wide they are.
CA SL55 91 litre slalom board - 41.7knots Sandy Point Easterly Bank 2011, KA23 Symmy
CA SP40 60 litre speed board I think?? - 46.5 knots 2013, Sandy Point A, KA20 Assy
Formula HWR and 10.7 vmg 76
Agree it is the fins size which is the main limiting factor
30.62 2 sec
Select to expand quotedecrepit said..Macroscien said..
>>>>>
Agree , to some extent. Above 30 knots we are all in interested in not so much volume but width or wet area that matter.
But there so far is strict correlation between board size and volume so for simplification we could stick clearly to volume >>>>
when you get to small speed boards there can be a lot of difference between manufacturers for volume/width, eg. slowy's boards seem to have more volume than others for similar width.
And I can't tell you exactly what the volume of my boards are, but I can tell you how wide they are.
You are right, I should be more general in " board size". It could be volume, width, just some description that allow us to compare and imagine board size.
But again width alone isn't enough as some boards could be relatively narrow but extremaly long at same time ( I think race boards looks like that).
Select to expand quoteDarrylG said..
Formula HWR and 10.7 vmg 76
Agree it is the fins size which is the main limiting factor
30.62 2 sec
I did one day experiment. So called "scurfing" , I think. On the windless day we attached rope to speed boat and start towing our-self on different windsurfing boards behind with quite reasonable speeds.
Used boards vary from Fanatic 130 L , Naish 110, Naish Supercross 84L. , then down to small kite board even ( i guess 5L ??)
Fin used from 42 cm , 32 down to 23cm to few cm on this kite board.
I was very surprised to find out that once board is planing the pulling force required to sustain planing is very little indeed.
I could easy hang on the line with one hand or two fingers when going full speed.
That will give me some idea what is actual resistance of specific board and fin when planing at speed on flat water.
Just couple kilo of force I guess.
Basically the smaller board and fin the less resistance it was.
But before board starts planing the force required to get board moving was just opposite (with most extreme kiting board - breaking the towing line on one occasion at the start)
Falcon slalom (131 litres) 37.04 knts 38cm talon
AB + 54 Slalom (78 litres) 43.42 knts 25cm speed weed
AB + Speed 46 (63 litres) 45.95 knts 23cm ka assy
Select to expand quoteMattDowse said..
Interesting topic! I am 5'10" and 105kg
The bear-away is the most important thing Macro, deeper you go the faster you go (as long as you are powered up)!
And I am still working on it!
Category 130-150L: 1998 Bic Vivace 149L Raceboard 8.6m Loft race blade 34.09 knots
Category 120-130L: 2005 Starboard 126L S-Type 6.3m Loft Switchblade 36.26 knots
Category 100-120L:2013 Carbon Art 117L SL67 7.3m Loft Switchblade 36.43 knots
Category 80-100L: 2010 Carbon Art 100L 60W Freeride 6.3m Loft Switchblade 38.94knots.
Fins I used are
Category 130-150L: 1998 Bic Vivace 149L Raceboard 8.6m Loft race blade 34.09 knots (JP36 weedy)
Category 120-130L: 2005 Starboard 126L S-Type 6.3m Loft Switchblade 36.26 knots (JP31 weedy)
Category 100-120L:2013 Carbon Art 117L SL67 7.3m Loft Switchblade 36.43 knots (Maui delta 23cm)
Category 80-100L: 2010 Carbon Art 100L 60W Freeride 6.3m Loft Switchblade 38.94knots. (Maui delta 20cm)
Select to expand quotetilldark said..MattDowse said..
Interesting topic! I am 5'10" and 105kg
Category 130-150L: 1998 Bic Vivace 149L Raceboard 8.6m Loft race blade 34.09 knots
Category 120-130L: 2005 Starboard 126L S-Type 6.3m Loft Switchblade 36.26 knots
Category 100-120L:2013 Carbon Art 117L SL67 7.3m Loft Switchblade 36.43 knots
Category 80-100L: 2010 Carbon Art 100L 60W Freeride 6.3m Loft Switchblade 38.94knots.
Wow that's impressive. I'd d love to come and trade notes with you on a windy day. I'm exactly 6 foot and 100 Kg (ex-rugby). Pretty much never get 25 knots but manage around 30 in 20 knots on 117 iSonic and recently 33 on 107 on a 20 Knots plus day. I'm really working hard on technique but often find lighter riders focusing on different things. I definitely prefer bigger sail smaller board as my combo but have nothing a a guide. Biggest problem where i sail is running out of water (i.e. shallow and or boat)
Anytime! Send me a PM if you are near the Central Coast NSW.
So far we don't have any results for boards above 150 L
( beside maybe Formula- but I don't know what volume Formula is .
1 Production Board (max 1005mm width),
3 Sails (with maximum size of 12.5m??),
2 Fins (with maximum length of 70 cm).
How it compare max speed Formula vs RSX vs big raceboard ??
Starboard GO ?? or similar beginner monster ?? can go above 30 knots ??
or ultralight sinker below 50 L ...
I think the most important ingredient in all this is wind strength verses water condition. Macro I've windsurfed at Shearwater in a SE with runout tide a few times and there is no way that water condition is worthwhile for any speed what so ever. It's rough as can be and the traffic makes it worse again. Take that same wind to somewhere smooth and you will have a whole other windsurfing experience. I saw your trip to Wellington Point and looked over your tracks with interest but you might want to come more often and follow some of the other members around to see what works for the GPSTC.
I'm enjoying the above posts to read how damn fast some of you have gone (seriously WOW) but water condition for the wind strength will be the limiting factor for VMAX pending board size (width).
As for myself I'm 78kg 180cm tall and in open water (Waterloo Bay side of Wellington Point) 10-12knot breeze up to 15knot gust = 121L JP Slalom VI 76cm wide, 43cm Select Fin, 7.8m Neilpryde EVO5, Course: square to the wind = 27.25kn 2sec
I'm new to GPS so this is my first ever session with the above listed gear. I'm sure given the opportunity for some flat water and constant wind strength that you can have some good times posted Macro. I'm just not sure that the broadwater is the most conducive to pulling great numbers.
Cheers
Marty
DarrylG - 30+knot peak with a 76cm fin and formula board 
Peter (Macro), here's one of Slowboats latest sessions - 38cm fin (his own design too) and an 82cm wide board gpsteamchallenge.com.au/sailor_session/show?date=2014-01-14&team=10
From a previous thread tooSelect to expand quoteslowboat said..
Having used the 137 a lot, here are a few points of difference to be aware of:
1) You can use small sails on it and it remains competitive (and heaps of fun). I've had some great days sailing it with a 7.0m, reaching speeds >37kts in open water. Its really fast like this. Lining up with WA's fastest on their smaller gear there was no disadvantage in the gusts. On GPS those days I was still a few knots faster. So it still works like a smaller board when you need it to. Which means you spend less time waiting on the beach for a wind change, or swapping boards all the time. It stays fun and competitive over a bigger range.
2) It holds big sails too. 9.5m seems OK. (Matty uses his from 6.6m up to 10.5m and reckons it works great).
3) Early planing- it planes super early for its width.
4) Gybing- it stays on the plane really well- out of gybes its unreal. And you can snap it around for some crazy tight gybes.
5) Trim stability. It handles a lot of chop, wind, and power before it gets out of control. It feels very neutral to ride, which means you dont get fatigued easily. Coming off a "lively" unstable board it might feel comparatively "dull", but if you actually check how fast you are going you'll find that its at least as fast. You can really push it with total confidence. The most fun setup is when a gust comes through and you can use the "nitro button" instead of sheeting out/backing off.
6) fin size- takes a pretty big range of fins. Ive used from 35cm up to 47cm depending on sail size and conditions. With 8.6m I run a 46 unless its lit, 7.8m I use 42-44, and 7.0m smokes with 40-42. In speed sailing mode you can go a lot smaller.
Overall its my most used board, and I'll say its the most versatile in the range.
Accepting that it is different to other boards, it does take a little while for some people to get used to.
You might take my comments with a grain of salt due to my involvement, but the guys over here who have seen the grin on my face 
when I'm sailing it will hopefully vouch for my honesty in making these statements. I'm enjoying my sailing more than ever.
this fin is 18cm and probably as big as you would need to go for the board width
the board is 60lt volume and 350w at the front straps , with a single concave through to the front of the fin with a slight v to the tail
Select to expand quotesausage said..
DarrylG - 30+knot peak with a 76cm fin and formula board
Peter (Macro), here's one of Slowboats latest sessions - 38cm fin (his own design too) and an 82cm wide board gpsteamchallenge.com.au/sailor_session/show?date=2014-01-14&team=10
Last 5 sessions on my 82cm board, 7.8m and various 38cm fins... water too shallow and weedy in places to use longer fins.
Lots of fun in very gusty moderate sea breezes at Melville.
