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26th August 2011 11:38 PM
Ken The basics we all want to know:

Board length, width, volume

Sail size, mast length, boom length

It seems so simple, but variations or misrepresentations do occur. Finally, Starboard got away from the "virtual volumes" on their boards and got real.

As with boards, different sails that have the same basic measurements do and should vary considerably in performance. We use them in different ways so design/performance specifics will vary based on what the designer was trying to achieve.
26th August 2011 03:28 AM
Farlo Hi Carlos, the upper part counts as sail area but difference in boom length, or in the overall profile of the sail, have a lot more impact, I think. And yes it is certainly possible to measure sail area properly, however it may not change our life or make sail choice easier. I guess the Overdrive and the Overdrive light wind have completely different behaviours for the same surface.
26th August 2011 01:35 AM
Unregistered You can change when rig depowers with mast choice and even amount of power available with adjustments but no matter what you do you can not alter the sails area. Rightly or wrongly it is the paramater we choose our sail`s by for that reason alone it should be measured accurately and by same process accross manufacturers.

Its not complicated.

Just measure the sail area by same method properly
26th August 2011 01:31 AM
carlosgp5 Yeah Farlo,I might sound dumb, but the first poster didnŽt make sense to me... lenghts of luff, and boom donŽt give sail area.
If I understood your post, you say that with the sail rigged and fully downhauled, the upper part, where the leach is open, would not count as sail area?
I find this subject very interesting...
For example, now severne has de Overdrive 11, and the Overdrive 11 light wind. If you get both unrigged and put on the floor one on top of other, you realize the differences in boom lenght and top width, however, both should have same area.
IŽll give it a try sometime, IŽll photograph and measure it on a Cad software, as someone gave the idea on previous post.
Cheers
25th August 2011 11:58 PM
Farlo Hi Carlos, this is true but the top of modern sails is mostly designed to release excess pressure. It's pretty obvious on some models where the whole upper part will dangle down sadly when rigged. IMHO comparing surfaces whether or not accurate gives only a very rough indication, notwithstanding other factors (design, mast, downhaul, etc).
25th August 2011 08:17 PM
carlosgp5 The sail is not a triangle, the width of top (from the leech to the tip) will completely affect the sail area.
I think so, anyways...
Cheers
25th August 2011 05:45 PM
Unregistered Think some posters are plain thick !!!

Original poster didnt say his sail measured big ; he did not criticise his( or any other sail for that matter). He pointed out ,quite rightly, that there are discreprencies in measuring AREA of sails acrross manufacturers...(and sometimes within ).This is a fact....full stop...Why the advice about masts ???? Whats that got to do with AREA. I have a Gaastra 7.5 GTX; in size terms it equates to an 8.0 in other manufacturers (or other years perhaps) Its something we learn to deal with by using sails but there should be more uniformity in measurements.

Poster no.19 ; are you poster 10 ?? If not try and be original...


There should be more objectivity in our sport...Fact.
22nd August 2011 10:55 PM
UnregisteredFloyd Nice one Ken..
Perhaps we could put Farlo`s shoes in it too !!!

Good winds

They still aren`t letting me on !!!

Always though Tush were constant curve (and Gun ??) NP are flex top ??? Learn something everyday...
22nd August 2011 09:49 PM
Ken I am delving into an area where I have no expertise, but it seems like you could take photo of an unrigged sail from above, laying flat in a specific sized space (say a 6 meter square box or smaller for smaller sails) outlined with a line.

With the photo and some computer software, it seems like one could come up with a program that would instantly give you the "sail occupied" space inside the box, thus providing the exact size of the sail.

This way, everyone making sails and using the same software would be able to measure sail size consistently and accurately. A universal process, isn't that refreshing.
21st August 2011 03:51 PM
Farlo Windsurf is not less objective than garment for instance. My shoe size varies from 41 to 44 according to brand/models and so on with pants, shirts, jackets. May be an inherent unaccuracy in textile manufacturing or changes happening between design and production, plus each brand may have his own method of measuring. Anyway you can't compare different sail models by their "exact" surface, whatever it is. And for similar cuts, boom length seems a better raw indication of power. IMHO the top is designed for low drag so a few more cm do not matter that much. This been said it is true that board volume could and should be accurate, although it is just one amongst many factors. Over the years I've been trying dozens of 100ish boards. Some were real pontoons and others semi-sinkers (for a stable bodyweight of course).
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