Gaastra Matrix 6.5
Available in seven sizes in 0.5m increments from 5.5--8.5m the Matrix is
a six batten sail that is billed to suit a wide range of uses, from
beginners learning to windsurf through intermediate to advanced freeride
cruising. It was the only sail on test to be provided with an RD (or
skinny) mast.
The Gaastra was somewhat smaller than its rivals (even those quoted as
6.4m) when we laid all the sails on top of each other to compare sizes,
but this was not evident in its power or speed.
Rigging: The 6.5 Matrix sets on a 460 mast with 6cm of extension.
We found it straightforward to rig on its own 460 RDM Gaastra 75% mast
which has a very stiff top bend curve and low to average overall
stiffness. As you would expect with a stiff-top mast the sail has only
moderate twist on the leech. However, there is plenty of rotation
particularly in the 2nd batten (from the bottom) and we found it set
well with a bit left in batten 1 and 3 as well.
Although there is little pre-set shape cut into the sail (noticeable in
the bottom batten only) it still sets with a fair amount of fullness
really quite high up in the sail. The most noticeable feature of its set
is the large amount of very soft spring in the body of the sail if you
press on the sail a foot or two behind the boom inhaul.
It's not a particularly 'set critical' sail, performing well in a
variety of set ups, but working best without any significant positive
outhaul.
On the water: Very comfortable and very flexible. It is easy to sheet
correctly and every gust transfers into power as the foil moulds itself
to the wind. The amount of flex and spring is very clear and partly
responsible for excellent acceleration and top speed. It also makes the
sail extremely forgiving in heavy chop, although some found it almost
too soft and elastic and thus lacking a bit in directness.
It allows very easy manoeuvring of the board and goes neutral well
through manoeuvres for easy handling.
Overall: Generally (though not unreservedly) popular with the guesters,
but a definite hit with the testers, who found it both faster and more
comfortable for blasting and manoeuvring than most of the opposition.
Above all, despite its small size, it had a real competitive edge over
its rivals without sacrificing comfort in any way. We would very
strongly recommend this sail for any recreational freeride sailing, drag
racing and recreational slalom.
Mast changes: Undoubtedly some of the extra spring and consequent
advantages in speed and acceleration were down to the RD mast. Rigged
with a standard diameter (SD) mast of similar stiff-top bend curve (Maui
Sails SRS 75) but increased stiffness (27.5 instead of 24.4), the sail
felt stiffer with a clearly more direct feel and slightly better top
end, but it lost a bit of response, early planing and speed. This could
be down to the extra stiffness or the extra mast diameter, or both.
Overall we preferred its own mast for most conditions and uses but the
stiffer SD mast was good in well powered up conditions.

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As you would expect with a stiff-top mast the sail has only
moderate twist on the leech.

I heard that as of 2007 Gaastra went to more constant curve masts. Could you please give us the curve specs for the recomended mast(s) for this sail?

The information that nobody is talking about can be found here as well: www.peterman.dk/windsurf-mast-article-gb01.htm

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***) The new sail designer for Gaastra (Dan Kasseler) came from Naish Sails, where he designed sails around some (probably) traditional Constant Curve masts. At Gaastra he inherited the top stiff masts from Barry Spanier and Phil McGain, and he has built the first Gaastra race sails (the Vapors) around these masts. From the start Kasseler said that he'll continue to design sails around those original Gaastra (former "Ignition") masts - but from 2007 Gaastra without any announcement changed their race masts to Constant Curve and presumably changed their sails accordingly. At Naish Sails he also had a great success building sails around such more traditional masts - for instance the sail that helped Finian Maynard making his World speed record in the autum of 2004.

Standards are wonderful things, it would be fantastic if every company used the same specs of mast so you could mix and match easily. Prior to learning the above information I would never have bought a gaastra due to it not using a standard curve, but now I'd be happy to buy one (post 2007)... way to go Dan

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Gybesports said...

Gaastra Matrix 6.5
The Gaastra was somewhat smaller than its rivals (even those quoted as
6.4m) when we laid all the sails on top of each other to compare sizes,
but this was not evident in its power or speed.

So which brand if any are giving correct sizes?

Sounds like justifying the error in size with power & speed.

If I buy a sail and they say it's a 6.5M I expect it to be that size, there is no excuse for inaccuracy with todays computer programs.

Wow sticky topic boys.
1) There is no mention of the actual variation in size of the sail. I will get back to you on that because I would like to ask Dan directly how the sails are measured and it is most like that because of recuts during devlopment and the need to have the sails work perfectly rather than be the exact size to the square mm then once a final standard sample is agreed on then that is sent to the factory to be made exactly. If the sails was racing the rules only say that the sail cannot be above a certain size not that it has to be exactly a certain size
2) Masts if you have a copy of board mag from last month a good comparison of measurements for flex top vs stiff top masts was discussed for RDm masts which are relevent to the test above. I don't have the copy in front of me but traditionally the masts now refered to as Stiff top by boards mag are what we have been known in the past as constant curve. But Boards mag have redefined the bend curve ratios so now we have a range from stiffest top Like Maui Sails to flexiest top like NP and North. In between we have a lot of masts as far as we are concerned
Gaastra , Fiberspar and Powerex are closest to the Gaastra Luff curve in that particular order.
3) When a new designer comes on board there is a very short window of testing and development from concept to delivery time so it was never going to be possible to change the masts in one hit but gradually as the mast construction evolved more because of the need to reduce weight and increase durabiltiy the bend curves have changed slightly over time as more reinforcement was put in certain areas.
4) Barrier Spanier goes on a lot in his blogs about tollerances in Sail making and how hard it is to get the exact Sail he made in the loft to come out in production because the stacks move around etc. Not all sails are laser cut on a vaccuum table one at a time.

I'll post again when I can look up the articles relevent to the bend curves.