Online Gear Calculator

Windsurfing Gear

What sizes and quantity of gear do you actually need?

Use this web application to calculate the number of sail or kite sizes you need based on your weight and desired target wind range.

Click below for the perfect quiver calculator:

This is something I have been playing around with for ages, and I finally got a chance to finish it. The idea was to design a web application that helped the average weekend warrior windsurfer or kiteboarder figure out just what sizes and quantity of sails or kites they needed based on their weight.

I have to thank James Douglass (who has a great blog) for creating his Windsurfing Calculator spreadsheet and Kiteboarding Calculator spreadsheet, on which this web application is closely based. I have to say, James did all the hard work figuring out these formulas, all I have done is change the way the results are calculated and presented.


Use this tool to run scenarios around your weight and target windspeed to get an idea of the range of sails or kites that you might need for different conditions. This should help you make more informed decisions about your quiver. This is particularly useful for heavier or lighter sailors who may find that the standard vendor recommendations not quite right.


Sailor weight input

Use this input to enter your weight. This can be in either kilograms or pounds, depending on which side of the pond you are on.


Sailor experience level

Here windsurfers need to select an experience level. This can be either beginner, intermediate or expert. I would select beginner if you are really just starting out. Intermediate if you can up-haul, hook-in and plane. Finally, expert if you can reliably do a carve gybe and stay dry.

Windsurfing activity

Here windsurfers need to choose their intended activity: freeride, slalom, wave, formula, wave, weed & shallow water and kids. The chosen activity sets the sail range and recommended fin sizes.


Kite type

The kite type lets you choose between either a bow or trainer kite.


Target windspeed

The target windspeed is that windspeed sweet-spot you want to build your quiver around. This could be based on the average windspeed at your favorite launch site, or perhaps more usefully, the prevailing windspeed during your favourite sessions from past season. Some ideas might be, 12.5 knots for mostly light wind sessions, or 16 knots for a fully powered up session where the lulls and gusts may fall 3 knots either side. 18 knots might be good if you live somewhere where the wind gods smile down upon you ;)

Wind range

This is particularly important for kitesurfers, because it is challenging to kite in less than 10 knots, regardless of kite size and it is also considered very dangerious to kite in more than 30 knots even with the right kite size. Nevertheless, there is no point having a quiver that covers a range or wind speeds you never go out in, so use these inputs to set your desired range.

Gap between sails or kites

This sets the gap in knots between sails or kites. Generally windsurfers will want a gap of about 3 knots, whereas kitesurfers should choose 4 knots.



Windsurfing quiver

The results for windsurfers are pretty straightforward. There is a list of recommended sail sizes for your quiver down the left hand column. This is followed by weight adjusted fin lengths plus or minus a value to compensate for stronger or lighter winds. Finally the recommended wind speed appears in down the right hand column.


Kitesurfing quiver

The results for kitesurfers are also pretty straightforward. There is a list of recommended kite sizes for your quiver down the left hand column. This is followed recommended wind ranges from light to strong. Notice how the kite range in the default example overlaps quite nicely.


So how did my hodgepodge of mostly second hand and some new gear compare to my recommended perfect quiver?

My perfect quiver

115kg intermediate sailor with a target windspeed of 16.5 knots

Well for the most part not too badly. I have the following quiver.

  • Severne CodeRED 11 m2
  • Ezzy Freeride 8.5 m2
  • Gaastra Matrix 7.5 m2
  • Gaastra Pilot 6.5 m2
  • North Duke 5.9 m2
  • Loft 360 5.1 m2

So it turns out I do have too many sails, specifically the 6.5 m2 and 7.5 m2. I should really just have a single 7.0 m2 to fill this gap. This pretty much matches my experience on the water with these sails. I often find that they are just too close together. It would have been nice to know this before I bought them - even if I did get them on second hand on eBay.

Posted by Henry Thomas, 10 years ago on Sunday, May 1, 2011


James Douglass said...

Wow, that's really nice! I can't think of anything I would do differently. Well done. :)


Posted 10 years ago on Sunday, May 1, 2011

Jacek Polubiec said...

Great website. Here are some specs followed by a question: Sailor's weight 270lb Board 271cm by 85.5cm 171L (Starboard 2011 GO 171L) Fins 52cm (standard) or MFC 40cm Weed Sail 6.5m Gaastra

Question: What wind speed should be sufficient for this combination to plane?

Posted 8 years ago on Saturday, August 25, 2012

Henry Thomas said...

Hi Jacek,

With that board you will be able to plane - as you have plenty of volume. With your weight with a 6.5 sail you will need about 20 knots to get planing. So you may want to look into getting a bigger sail depending on what your prevailing wind conditions are like. See if you can find a wind rose chart for where you sail and work out what the wind speeds are likely to be on average. Then use the gear calculator here to figure out what you might need. If you are just learning, the 6.5 is going to be a hand full anyway, so yo may want to just practice getting into the straps etc, then go out on a stonger day. I learned to plane on my Starboard GO with a 5m sail in winds gusting to 26 knots. The great thing about a smaller sail is they are lighter and easier to handle when you are learning.

Posted 8 years ago on Saturday, August 25, 2012

jeff Irvin said...

Hello Henry Really appreciate the videos- thanks

Been at it for the past 9 months - returning to the sport after an unsuccessful try in my early 30's now in my 50's!

When should a beginner consider a suggested intermediate board?

I had my first successfull planning sessions thanks mainly to your videos on planning the lazy way and taking the advice to get into a harness.

Following your lead Im in a dakine seat harness.

My board is a fantic viper 220l 85cm wide. Im 6ft and weigh 90kg. Use mainly a north 6.5 sail and generally sail at lake Cootharaba. Thanks to a friend getting out of the sport I have 6m, 5m, 4m and 3.7m sails - too many!!

My main question - shoulsd i be looking at a next board now or wait!

I have access to old school boards - bombora 295 and F2 comet. I can uphaul on the comet but the bombora is a handfull. I haven't tried planing on eithe of these boards. I can beach start both of them.

Having enjoyed the experience of planning so much I want to spend money on the sport!!

Currently 2 secondhand boards take my interest- 1. A 2007 Starboard Go - 249 cm, 155 litres mainly because I like what you say about the board.

2.2000 Bic Techno 283 152 litres - good online reviews

The calculator suggests 147 litres as a first short board.

So what do you suggest? Stay with what Ive got or spend some money?

The other motivation to buy a second board is my 11yo daughter and 8yo son had a training day and want their own gear. This to me suggests the Go 155 may be the better choice.

cheers Jeff

Posted 8 years ago on Tuesday, October 9, 2012

Henry Thomas said...

Hi Jeff,

Welcome to the sport and great to hear that the videos helped. Planning to make some more this summer.

I would advise on getting the Starboard Go. True, the Bic techno is a great and very tough board, but the construction leaves a sharp lip around the outside edge which can cut your shin very easily. My mate Gavin has a Techno 147l, but ended up purchasing a new Go 171l after enjoying using my Go board so many times.

Regarding the Go - what can I say - its big, stable, planes early when you get your feet into the outboard straps, its great for learning and progressing and is still the board I use the most because it reliably handles the broadest range of conditions.

Its only limitation is when it gets too rough on the water, or when waves get too big. Still rough choppy conditions pretty much suck no mater what board you are riding, and you are not going to get any waves on lake Cootharaba anyway.

The only other board you may consider is a longboard like a Starboard WindSUP (10' or 12'). My only criticism of the Go is that it is a bit of a barge, so not very fun in sub-planing conditions. So here is the rub - if you can go windsurfing whenever the conditions are optimal - i.e. you have flexible work hours and an understanding wife, then a short wide board is a blast, however if you can only get out on set days like Saturday morning or Sunday afternoon, then a longboard may be better, because you can SUP, surf, light wind windsurf and plane - all with the same board. Obviously its a compromise all round board, but its still worthy of consideration.


Posted 8 years ago on Tuesday, October 9, 2012

jeff Irvin said...

Thanks Henry I've just picked up a second hand Go 155 off seabreeze Will post on my efforts with it

Cheers Jeff

Posted 8 years ago on Friday, October 12, 2012

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