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eSurfer
25th April 2010, 04:35 PM
I have a GO 155 board, and have the fins which followed with the board (Drake R13 Race NR 520 S-Flex + Shallow 410). I do not sail in shallow water, so the lengt of the fin would not it selves be a problem.

I am uncertain of when to use which fin, and whether I should buy additional fins.

The specification of the board on the Starboard web site, gives a fin range of 48-58 on the board. I tried to use a fin size calulator that I found on a web page, and put in the information of weight (83 kg) and sail size (6,5 and 8), but then got recomendation for 37 - 48, i.e. outside the range that Starboard has spesified. Thus, I do not think the calulator was much help.

Hope someone could provide some explanation of which fin to use, for example, should I use the Shallow fin with the smallest sail and when the wind is strong..

joe_windsurfer
25th April 2010, 07:07 PM
i am interested to hear the response from SB staff
this discrepancy is NOT unique to Starboard

a local windsurf shop told me the sail range of more than 3 meters was bogus
in terms of ideal sails with the board

this seems to be true in terms of the fin specifications
i still use a 6.0 and 10.0 on my 160, but my fin of 40 cm is outside board specs and somewhat longer than ideal for a 6-oh, butt it works for me

as i said - am interested to see SB staff comments on fin vs sail discrepancy

eSurfer
25th April 2010, 09:22 PM
Regarding specifications on the Starboard web page, I may add that I am a bit confused. The GO 155 has a spesified wind range of 5.0-10.5 m2, while Futura 155 (same shape and measures as GO - except weight) have a specified range of 7.0-10.5, while the specified fin range for both boards are 48 - 58.

Roger
25th April 2010, 10:52 PM
Guys,
The 41 cm fin that comes with the GO boards, Starts is a trainer fin.
It is short so that smaller sailors can easily beach start these board when their skill level
gets up to beach starting.
They are intended to be used with small trainer sails (generally 5.0-2.5 m2 lightweight sails that are easy to uphaul and sail for beginners).
With a <= 5.0 trainer sail the GO does not need any larger fin.
For regular sailors on sails larger than 5.0 m2, you can use the Shallow Water 41 if you have shallow water and with smaller 7.0-5.0 m2 sails. The 41 cm is not a performance
fin, but it works.
When you start sailing the GO in performance mode, then the width of the board almost
demands at least a 48 cm fin for sails under 7.5 m2.
When you get to 8.5 m2 the OEM 52 cm Drake works pretty well.
If you put a 9.5 or 10.5 m2 rig on the GO, you need more fin (i've used up to 62 cm vert. race fins on the GO board) so you can get planing early.
Back in the day, when the GO first arrived, there was a "full race" wood version that won
several national championships.
As far as a 3m spread on sails, Starboard has always had a huge spread on the "multi
mission" boards like the GO and has included the small trainer sails in that range.
What is the best fin size?
Depends entirely on the width of the board, the windspeed/sail size, sailor weight (to a lesser degree) and sea conditions.
The "fin calculators" never seem to include the tail width of the board, and that's (IMHO) perhaps the most critical factor.
The supplied 52 cm is pretty much right in the mid range and should be pretty good with
6.5-8.5 m2 rigs.
If you are fully powered on a 6.5 m2, then 4 cm smaller would usually be better.
If you are barely able to plane on an 8.5 m2 the 4 cm longer would help you get planing.
If you have a huge sail, and want to get the GO planing as early as possible, borrow a 65-70 cm Formula fin and you will get planing very early.
Not good for beyond maybe 12 knots, and slow top end, but you will be planing.
"Calculators" never employ enough of the important variables to give you more than a ball park idea, and they do not take into consideration the differences in fin designs and
the different sailing disciplines.
Hope this helps,
Roger

eSurfer
26th April 2010, 01:30 AM
Thank you for an informative answer

joe_windsurfer
27th April 2010, 05:22 AM
roger you da man ! :-)

however, you are just confirming that the numbers are mis-leading
ie the fins n sail #'s do NOT correspond

i would prefer to see somthing like ideal sails x-y and matching fins a-b with the possibility of training sails down to 5.0 with 40 cm fin :-)

still a GREAT board from all i see n read & definitely good 4 training!!!

thx for listening

Architect
2nd May 2010, 02:31 PM
I've also have a 155 GO which is giving me a load of trouble from getting on the plane.

I've got a 6.0 m2 Severne Synergy Rig and I feel like I can never really get going...

I've tried the longer fin - and it eases the problem somewhat, but the 6.0 m2 sail with oem 52cm fin with a 110kg (me) rider just isn't enough to pop out even at 18-20 knots...

Easy planing... I don't think so... even with lots of pumping nothing happens. I've even had a mate who weights 20kg less then I do and has 10 years of experience try - "Didn't even get close" - his words.

I'm looking to get a 7.5-8.0 sail with a 460 75% mast in the coming months should I make getting a bigger fin a consideration as well?

Roger
3rd May 2010, 12:06 AM
Hi Architect,
Well, if I had to guess what's not working here, I'd probably say that the sailor weight,
sail size, and board size are not a very good match.
At 110 Kg. (242.5 lbs; 17.3 stone) I would have suggested a GO 100 or GO 200.
At your weight, you need WIDTH to get you planing early.
What year is your GO 155?
I have a friend who is over 300 lbs. (yes, a mountian of a man @ 136 kg./21.4 stone).
He gets planing in around 12-14 knots on an early 2001-2003 Start thats 110 cm wide, with a 10.5 m2 rig. He will never sell that board as no one has ever made 110 cm wide boards except the early Starboard Starts.
He sails this combination with a 70 cm fin (or a really huge 53 cm weed fin) to about 20 knots.
Heavier sailors have the weight to keep a really big wide board on the water in conditions that would have a 180 lb. sailor airborne (not by choice) most of the time.
If you want to stay with a semi sinker (like your GO 155 at your 110 Kg.) you are correct,
you will need at least an 8.5 m2 rig (10.5m2 would be better).
At your weight, a 6.0 m2 rig is pretty much a "trainer sail".
Not what you wanted to hear I'm sure, and I can elaborate more if you can give me a better idea of your sailing conditions.....i.e. salt water or fresh.... min. windspeed you will consider going out in..... how much wave and chop you get a 15-18 knots.
To summarize, I think you have the wrong board for your weight, and are using a sail that is better suited to a guy your size for about 22-25 knots.
Hope this helps,
Roger

joe_windsurfer
3rd May 2010, 05:23 PM
am sure roger meant GO 180 and not GO 100 :-)
as usual - roger is spot on

at 100 kilos, and fairly new to shortboards, my first sail was an 8.5
the board is 160, so - close enough to your 155
wanted more TOW with planing and purchased a used 10.0 kit
with that kit + 53 cm race fin , I can plane earlier than the middle weights
my 6-oh is definitely for BIG winds - up to 50+ kph
after that i am off the water

u can plane on the GO 155 i am sure - more sail and more fin

at 10 kilos more than i - not sure about board size
for some of this you can look at james douglass' sail calculator
butt as roger says calculators don't always work with fins ...

just used the calculator
for me 160 liter with 8.5 = 175 with 9.5 for you !!
so, once again roger was right - u need big board and big sail !!!
i actually lost weight for windsurfing :-)

GOOD LUCK

Architect
5th May 2010, 09:35 AM
I've got a the 2010 GO.