Just wondering ,when they rate a board on its sail size ,are they rating it on its wind range or strength ,rather than what sail size it will carry ,?
eg..I have a 115 Patrik, best sail size is 7.0 to 8.0 .it will carry a no cam 8,5 no problem ,but it needs to be constant
i have had some good speeds on it with a 6,5 ,but a smaller change of fin was needed to keep it from lifting out of the water .
why the question ,i just brought a 2016 isonic 124 litre ,best sail size is 7,8 -9,5 .
does this mean a 7,0 won't be as comfortable ..

What are your thoughts .? on board guide lines .

Is it something to do with the lift n downforce a sail produces? You need a certain amount of lift to unstick the board n get it planing. But then you also need a certain amount of downforce to keep it on the water at speed? Im just guessing here.
Sailquik???

I'm thinking it could also be hull design ,,for max lift .on the isonic .124 .

i had a bigger and wider free ride board 130 titan 84 wide ,sail range 6,0 -8,5 But very narrow in the tail .

Sail size numbers for a board vary a lot between different manufacturers . Some will give you "ideal" numbers that assume you got plenty of boards and sails and will switch both board and sail when the wind changes. Your Patrik seems to be like that. Others give you the widest possible range - I think I've seen 3.0-9.0 (albeit on a beginner board). Most are somewhere in the middle, and would include an 8.5 in the range for a 115 l slalom board.
You can often go beyond the given range without much problems. You may need a smaller or larger fin, and it depends a bit on conditions and body weight. For example, the iso 124 may work well enough with a 7.0 on flat water for a light weight sailor who gets going on a 7.0 when a heavier guy would need an 8.5.

Makes sense that the sail size range posted is based on the boards Hull shape, intended range.

using a much smaller sail is feasible, but the board itself becomes too large, unmanageable. A smaller fin change will help and larger sails same thing with larger fin.

The recommendations are based on sailor weight average of 175lb / 79kg. Each company probably has its own parameters to make the sail range suggestions. Like that board volume will vary, more consistent of late.
a brand x sail will have a different range of use than brand y

to all above YMMV .

Just go out a day with the 6.5 and then switch to a smaller board and you will see how much easier and faster it is. The big board will be slower to accelerate and harder to keep under control, more so if its choppy.

forceten used a good word when he suggested the 'intended' sail range, because the manufacturer is just stating what the board designer thinks will suit this hull design in terms of sail sizes.

But the performance of a hull size and shape will also be affected by how heavy you are, by the water conditions of the day, and by what type of windsurfing you do.


And for example, a 100litre freestyle board will typically have a sail range of 4.5 to 5.8 for normal freestyle use, but could probably carry a 6m+ sail if you added a bigger fin, and might also be happy with a 4m rig if the water was flat.

A slalom board in the 100 litre size would probably come with a recommended sail range of 6m to 8.5, but for slalom you would also match those sail sizes with a long fin.

I have a Dyno 95 wave board which has a recommended sail range of 4.7m - 6.5m rigs, but I frequently use it with a 4.4m and have used it with a 4m rig when matched with a smaller centre fin. The biggest sail I have put on it is a 5.3, and I'd have to be desperate to want a to use a 6.5 on this board. If I wanted to use the board with a 6.5 I'd need to fit the long single fin option and I'd have to shift the footstraps to the outboard setting options to ride the board off that fin.


So these suggested sail size ranges are just a guide.

I'm 98 kgs .

fin recommendation s for this board are 38-46 ..,i have a 40 & 45

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Tardy said..
Just wondering ,when they rate a board on its sail size ,are they rating it on its wind range or strength ,rather than what sail size it will carry ,?
eg..I have a 115 Patrik, best sail size is 7.0 to 8.0 .it will carry a no cam 8,5 no problem ,but it needs to be constant
i have had some good speeds on it with a 6,5 ,but a smaller change of fin was needed to keep it from lifting out of the water .
why the question ,i just brought a 2016 isonic 124 litre ,best sail size is 7,8 -9,5 .
does this mean a 7,0 won't be as comfortable ..

What are your thoughts .? on board guide lines .

Have a mate with same board 2016 isonic 124
His go to sail is 8.6 full camber NP race
He says that combo is great
He's up and going in 15kts

I have an Isonic 124 from 2016.

8.6 is perfect with 44 Winheller
7.8 is OK wiht 44 Winheller (better then with 42 Drake DW)
9.6 is possible but not perfect (48 Deboichet)
7.1 I never tried
6.4 I tried because I had no other board that quite strong day (with 42 Drake DW), harsh ride but good for 55km/h, a smaler board will be way more comfortable.

I wanted to add something to this post. On my 115L Naish Starship, I use 3 sails and 3 fins for wind strength. My 27cm fin is the touchy one. It spins out super easy. Does that mean the fun is too small for the board. That's my go too fin when it's blowing in the low to mid 20s.

Correction: Does that mean the fin is too small?

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MagicRide said..
Correction: Does that mean the fin is too small?

Not necessarily.

A suitable fin size, depends on a couple of things...
a) the sail size - smaller sails produce less lift, so less lift needed from the fin
b) the boat-speed - the faster you go, the smaller the required fin for the same lift
c'ish) the board-width at the finbox - a wide board has more leverage over the fin, so a small fin is easier to spin-out.
d'ish) the conditions of water - chop size, water depth, etc
e'ish) your technique/skill - if you can lollypop/flickyspin, then you probably have leet skilz

Note that sail size also tends to define the size of board you would choose and thus depends on your weight + wind-speed. Lets ignore fin brand, as some fins are better than others. And lets ignore the fact that money doesn't grow on trees.

So... to simplify the choices, just focus on sail size and board size... that will define the size of the fin.

For a 115L board, the smallest sail is going to be a 6.0m sail - that is mostly independent of body-weight. At my body-weight (69kg) I might use that in conditions up to 20kn, vs a larger person (say 100kg) would use that up to 27kn. ( Personally I would only use that small a sail if it was gusty, because a consistent wind with a 6.0m is more fun with a smaller board. ) A 27cm is probably about right. The sail / fin choice largely independent of body-weight, in that you need enough fin-lift for those points above.

Obviously sail size, does depend on body-weight for a given wind-strength... but that is why the recommendation of "just focus on sail and board size", because people usually automatically take into account their own weight and water-state.

If it were to increase sail size to 6.5 or 7m, the fin size would increase proportionally (again, not really directly dependent on body-weight).


... what size sail are you using with this 27cm ?

In addition to what Mathew said you also haven't said what fin type. Not all 27cm fins are the same size: A 27cm upright slalom fin is going to be much smaller than a 27cm wide base wave fin, & there is plenty of variety in between...

The 27cm is a MFC wave fin. I'm 170 pounds and use this fin with my 5.2 Ezzy Legacy sail. Yes, the water is choppy in those conditions. The board is about 66 wide I believe. The sail range for that board is between 4.5-7.0. I sail on lakes and Columbia river gorge with that fin. I bump n jump and like to surf big chop. I have to be very conscientious on back foot pressure with that fin to help eliminate spin out

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MagicRide said..
The 27cm is a MFC wave fin. I'm 170 pounds and use this fin with my 5.2 Ezzy Legacy sail. Yes, the water is choppy in those conditions. The board is about 66 wide I believe. The sail range for that board is between 4.5-7.0. I sail on lakes and Columbia river gorge with that fin. I bump n jump and like to surf big chop. I have to be very conscientious on back foot pressure with that fin to help eliminate spin out

Hey Magic, Funny I use the same exact fin on my 100liter board but in the 24cm size. I am about your weight & 5.0 is the sweet spot for that fin. I reckon 4.7 to 5.2 even 5.7 should work pretty well with a 24cm, so a 5.2 is probably pretty solid with 27cm - perhaps even on the large side. Sometimes riding oversized fins can mask stance & or set-up issues. These might include harness line position & or mastfoot placement.

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gorgesailor said..

MagicRide said..
The 27cm is a MFC wave fin. I'm 170 pounds and use this fin with my 5.2 Ezzy Legacy sail. Yes, the water is choppy in those conditions. The board is about 66 wide I believe. The sail range for that board is between 4.5-7.0. I sail on lakes and Columbia river gorge with that fin. I bump n jump and like to surf big chop. I have to be very conscientious on back foot pressure with that fin to help eliminate spin out

Hey Magic, Funny I use the same exact fin on my 100liter board but in the 24cm size. I am about your weight & 5.0 is the sweet spot for that fin. I reckon 4.7 to 5.2 even 5.7 should work pretty well with a 24cm, so a 5.2 is probably pretty solid with 27cm - perhaps even on the large side. Sometimes riding oversized fins can mask stance & or set-up issues. These might include harness line position & or mastfoot placement.

Small world! To add to this, if I'm perfectly powered up on the 5.2, I'm using my 34cm stock MFC fin in the 19 -22 mph wind range. But, from 22-26 mph wind range, I rail up using the 34cm fin, so I pop the 27cm fin in and it sails great, but like I said, is sensitive to spin out. Especially when the board is sailing over big chop with such a little fin. So if I pop the 27cm fin on in the 19-22mph wind range, the board has trouble getting on plane until wind hits 21-22 mph. This is the stock 34cm I use too.

I also use this 34cm fin on my 6.0 sail and it sails great too. Then I throw on my 38cm MFC K one freeride fin when on my 6.8 sail. But back to the 34cm fin, it just seems to sail the best with either the 6.0 or 5.2 sail. The fin has lots of grip. But I find the 27cm fin losses grip very easy and of course spins out a lot. The 27cm seems if anything more on the smaller side to me. I don't consider that fin oversized at all with 5.2 sail on the 115L board. I wonder if a 30cm fin would be in the sweet spot when the 34cm fin becomes overpowered?

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MagicRide said..

gorgesailor said..

MagicRide said..
The 27cm is a MFC wave fin. I'm 170 pounds and use this fin with my 5.2 Ezzy Legacy sail. Yes, the water is choppy in those conditions. The board is about 66 wide I believe. The sail range for that board is between 4.5-7.0. I sail on lakes and Columbia river gorge with that fin. I bump n jump and like to surf big chop. I have to be very conscientious on back foot pressure with that fin to help eliminate spin out

Hey Magic, Funny I use the same exact fin on my 100liter board but in the 24cm size. I am about your weight & 5.0 is the sweet spot for that fin. I reckon 4.7 to 5.2 even 5.7 should work pretty well with a 24cm, so a 5.2 is probably pretty solid with 27cm - perhaps even on the large side. Sometimes riding oversized fins can mask stance & or set-up issues. These might include harness line position & or mastfoot placement.

Small world! To add to this, if I'm perfectly powered up on the 5.2, I'm using my 34cm stock MFC fin in the 19 -22 mph wind range. But, from 22-26 mph wind range, I rail up using the 34cm fin, so I pop the 27cm fin in and it sails great, but like I said, is sensitive to spin out. Especially when the board is sailing over big chop with such a little fin. So if I pop the 27cm fin on in the 19-22mph wind range, the board has trouble getting on plane until wind hits 21-22 mph. This is the stock 34cm I use too.

I also use this 34cm fin on my 6.0 sail and it sails great too. Then I throw on my 38cm MFC K one freeride fin when on my 6.8 sail. But back to the 34cm fin, it just seems to sail the best with either the 6.0 or 5.2 sail. The fin has lots of grip. But I find the 27cm fin losses grip very easy and of course spins out a lot. The 27cm seems if anything more on the smaller side to me. I don't consider that fin oversized at all with 5.2 sail on the 115L board. I wonder if a 30cm fin would be in the sweet spot when the 34cm fin becomes overpowered?

They are 2 very different types of fins. The Freewave has allot of area in the tip & is thicker & more powerful. The K-one has a soft thin tip. It is a pretty quick wave fin that has very good turning ability but with a relatively upright base still goes upwind well. 34cm Freewave on the 5.2 will cover a multitude of stance sins. However as you found out it will be more difficult to keep the board in the water especially with that poweful tip.Also, as you start to demand more maneuverability of your board it will limit you. With harness lines If they are not balanced with hands free then there is your answer. Try moving your mast base back a bit & your harness lines lightly biased toward back hand - I mean by this is if they are perfectly balanced with hands free then move a tiny bit back. You will load the back foot much less with this stance.

Most people tend to be fin-dependent in that they have started off with spinout problems and 'staying upwind problems' and they have dealt with both issues by using a long or wide fin - which has then become a comfort blanket. Using a long fin can in fact keep you in a 'stance rut'.

The top tip here is to use the smallest fin you have and learn to live with it, if only for a period where you adjust your stance. You will never 'tail walk' if the fin is smaller and you will turn the board better. If you spinout too easily then shift your harness lines back, so that there is even load on your hands even when you sheet in or when the gusts hit. If you feel more pull on your font hand, then that is directed to the board via your front foot, rather than overloading the back foot.
With a smaller fin, you can also use the back half of the mast track and not the front half, meaning you are in a more upright stance with less load on the back foot. And the added bonus is that you should find you go upwind better.

Fin size actually relates to sideways load on the board tail, and that, 1) is a function of sailing stance - as I have just described - or else, 2) it's down to sail size or, 3) body weight.
For sure, heavier sailors using bigger sails will need bigger fins, but don't use that as an excuse to de-tune your board.
A 75kilos sailor using a 5m rig should be on a 24cm fins, not a 27cms or 30cms one. I'm 74kilos and when I'm on a 5.3m rig I use a 22cms fin and it works just fine. (If the water is flat, I can go shorter.) For a 6m sail I might try a 28cms, but that should also work for a 7m rig. If you use a 32cms fin then I'd ask what size sails are you using that with?
Have you heard the expression: 'The tail wags the dog'? That's what happens when you use too long a fin for the rig size chosen.

Interesting stuff! I guess I never thought my fins were too big per sail choice. My goal has always been to plane as early as I can without sacrificing much performance. I do notice when putting the 34cm fin with the 6.8 sail, I don't plane as early as if I would have had the 38cm fin with the 6.8.

I have always been front foot dominate as for foot pressure, to prevent less cavitation or spin out issues. Mast track is in the center, boom is balanced pretty well it seems, as I adjust harness line positions per sail size. Always seems to be a little more forward pull on the boom with ezzy sails, possibly due to a deeper luff pocket, but I adapt to it by leaning my upper body aft more, while still keeping forward dominate foot pressure. On my naish sail, it has less forward pull, and is more balanced, so I lean less aft with still forward dominate foot pressure. Should I be changing anything or any bad habits I'm explaining here?

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MagicRide said..
Interesting stuff! I guess I never thought my fins were too big per sail choice. My goal has always been to plane as early as I can without sacrificing much performance. I do notice when putting the 34cm fin with the 6.8 sail, I don't plane as early as if I would have had the 38cm fin with the 6.8.

I have always been front foot dominate as for foot pressure, to prevent less cavitation or spin out issues. Mast track is in the center, boom is balanced pretty well it seems, as I adjust harness line positions per sail size. Always seems to be a little more forward pull on the boom with ezzy sails, possibly due to a deeper luff pocket, but I adapt to it by leaning my upper body aft more, while still keeping forward dominate foot pressure. On my naish sail, it has less forward pull, and is more balanced, so I lean less aft with still forward dominate foot pressure. Should I be changing anything or any bad habits I'm explaining here?

Can you easily sail hands free? When you sail hands free does the mast side or clew side pull on you? How far apart are your harness lines? Sometimes it can be hard to tell if your lines are balanced when your lines are further apart...

Select to expand quote

gorgesailor said..

MagicRide said..
Interesting stuff! I guess I never thought my fins were too big per sail choice. My goal has always been to plane as early as I can without sacrificing much performance. I do notice when putting the 34cm fin with the 6.8 sail, I don't plane as early as if I would have had the 38cm fin with the 6.8.

I have always been front foot dominate as for foot pressure, to prevent less cavitation or spin out issues. Mast track is in the center, boom is balanced pretty well it seems, as I adjust harness line positions per sail size. Always seems to be a little more forward pull on the boom with ezzy sails, possibly due to a deeper luff pocket, but I adapt to it by leaning my upper body aft more, while still keeping forward dominate foot pressure. On my naish sail, it has less forward pull, and is more balanced, so I lean less aft with still forward dominate foot pressure. Should I be changing anything or any bad habits I'm explaining here?

Can you easily sail hands free? When you sail hands free does the mast side or clew side pull on you? How far apart are your harness lines? Sometimes it can be hard to tell if your lines are balanced when your lines are further apart...

I can sail hands free for about 3 seconds, when schlogging and up too about 4 seconds when planing. Harness lines are about 4 inches apart.

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MagicRide said..

gorgesailor said..

MagicRide said..
Interesting stuff! I guess I never thought my fins were too big per sail choice. My goal has always been to plane as early as I can without sacrificing much performance. I do notice when putting the 34cm fin with the 6.8 sail, I don't plane as early as if I would have had the 38cm fin with the 6.8.

I have always been front foot dominate as for foot pressure, to prevent less cavitation or spin out issues. Mast track is in the center, boom is balanced pretty well it seems, as I adjust harness line positions per sail size. Always seems to be a little more forward pull on the boom with ezzy sails, possibly due to a deeper luff pocket, but I adapt to it by leaning my upper body aft more, while still keeping forward dominate foot pressure. On my naish sail, it has less forward pull, and is more balanced, so I lean less aft with still forward dominate foot pressure. Should I be changing anything or any bad habits I'm explaining here?

Can you easily sail hands free? When you sail hands free does the mast side or clew side pull on you? How far apart are your harness lines? Sometimes it can be hard to tell if your lines are balanced when your lines are further apart...

I can sail hands free for about 3 seconds, when schlogging and up too about 4 seconds when planing. Harness lines are about 4 inches apart.

You need these:

chinooksailing.com/products/quick-lines-mono-harness-lines-available-in-18-20-22-24-26-28-30-lengths

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MagicRide said..

gorgesailor said..

MagicRide said..
Interesting stuff! I guess I never thought my fins were too big per sail choice. My goal has always been to plane as early as I can without sacrificing much performance. I do notice when putting the 34cm fin with the 6.8 sail, I don't plane as early as if I would have had the 38cm fin with the 6.8.

I have always been front foot dominate as for foot pressure, to prevent less cavitation or spin out issues. Mast track is in the center, boom is balanced pretty well it seems, as I adjust harness line positions per sail size. Always seems to be a little more forward pull on the boom with ezzy sails, possibly due to a deeper luff pocket, but I adapt to it by leaning my upper body aft more, while still keeping forward dominate foot pressure. On my naish sail, it has less forward pull, and is more balanced, so I lean less aft with still forward dominate foot pressure. Should I be changing anything or any bad habits I'm explaining here?

Can you easily sail hands free? When you sail hands free does the mast side or clew side pull on you? How far apart are your harness lines? Sometimes it can be hard to tell if your lines are balanced when your lines are further apart...

I can sail hands free for about 3 seconds, when schlogging and up too about 4 seconds when planing. Harness lines are about 4 inches apart.

You can test it on the beach. With the Monolines that Faff posted it is easy to tell if they are balanced just stand your rig up in the wind & hold it by the harness line instead of the boom - you don't even need to hook in. If anything the pressure will move toward the clew a bit when powered/overpowered hence the suggestion to move them back a bit from the normal COE.

Thanks for the advice!

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gorgesailor said..

MagicRide said..

gorgesailor said..

MagicRide said..
Interesting stuff! I guess I never thought my fins were too big per sail choice. My goal has always been to plane as early as I can without sacrificing much performance. I do notice when putting the 34cm fin with the 6.8 sail, I don't plane as early as if I would have had the 38cm fin with the 6.8.

I have always been front foot dominate as for foot pressure, to prevent less cavitation or spin out issues. Mast track is in the center, boom is balanced pretty well it seems, as I adjust harness line positions per sail size. Always seems to be a little more forward pull on the boom with ezzy sails, possibly due to a deeper luff pocket, but I adapt to it by leaning my upper body aft more, while still keeping forward dominate foot pressure. On my naish sail, it has less forward pull, and is more balanced, so I lean less aft with still forward dominate foot pressure. Should I be changing anything or any bad habits I'm explaining here?

Can you easily sail hands free? When you sail hands free does the mast side or clew side pull on you? How far apart are your harness lines? Sometimes it can be hard to tell if your lines are balanced when your lines are further apart...

I can sail hands free for about 3 seconds, when schlogging and up too about 4 seconds when planing. Harness lines are about 4 inches apart.

You can test it on the beach. With the Monolines that Faff posted it is easy to tell if they are balanced just stand your rig up in the wind & hold it by the harness line instead of the boom - you don't even need to hook in. If anything the pressure will move toward the clew a bit when powered/overpowered hence the suggestion to move them back a bit from the normal COE.

I have NP monos. They are very easy to adjust on the water on a skinny boom.