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Smaller board - difference in sail power

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Created by mthompson156 1 month ago, 21 Apr 2019
mthompson156
6 posts
21 Apr 2019 11:05AM
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Any thoughts on how much smaller a sail will feel when you drop down in board size? What I mean is:

Currently sailing 3.0 on an 86 liter wave board (thruster). Works very well. But we've had several days now where it is simply too much, and 2.4 would be the right size. Not many sails in that size, though.

Let's say I sailed the same 3.0 in those conditions on a 72 liter board (quad, perhaps). Would the drag/slower speed make that 3.0 feel like a 2.4 on the bigger board? Or is the difference not that large?

Sparky
WA, 904 posts
21 Apr 2019 1:33PM
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With more drag the 3.0 will feel bigger, like a 3.5.

ZeeGerman
104 posts
21 Apr 2019 2:23PM
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Once you've got the thing going, you'll be surprised how much control you gain with the smaller board. The sail won't feel smaller , but still you'll be able to sail higher wind speeds. Sails below 3 m don't really work, so smaller board is your only choice. What weight are you?

Foghorn
WA, 129 posts
21 Apr 2019 3:45PM
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Smaller board will have less drag but less flighty underfoot therefore more control in those conditions.

Stuthepirate
SA, 3475 posts
21 Apr 2019 5:36PM
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Where the hell are you sailing?
Too much on a 3.0?

decrepit
WA, 9111 posts
21 Apr 2019 4:17PM
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faster you go, the less sail pressure, fully powered a smaller board will be faster with less drag, so more manageable.

But yes, before you get planing there will be more drag and the sail will feel bigger.

Sounds like you are fairly light to be on a 3.0, an 86l will probably be too big for you in those conditions. I'd be matching a 3.0 with a 50l board.
As long as it isn't to gusty, becuse the smaller board is harder to get going, you need a bit more time to get planning, and it's harder on the shoulders.
But if that isn't a problem, I'm sure you'd enjoy it more.

mthompson156
6 posts
21 Apr 2019 10:43PM
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thanks for the responses, that all makes sense. I am 72kg, and sail in San Francisco.

forceten
655 posts
21 Apr 2019 11:37PM
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mthompson156 said..
Any thoughts on how much smaller a sail will feel when you drop down in board size? What I mean is:

Currently sailing 3.0 on an 86 liter wave board (thruster). Works very well. But we've had several days now where it is simply too much, and 2.4 would be the right size. Not many sails in that size, though.

Let's say I sailed the same 3.0 in those conditions on a 72 liter board (quad, perhaps). Would the drag/slower speed make that 3.0 feel like a 2.4 on the bigger board? Or is the difference not that large?


Question of interest, but it's math and that and windsurfing aren't bedfellows

using 86liters only, (not smaller fins nor quad consideration with more drag) and a decrease to 74 liters, ( which assured would be a wave board also, sharper rails etc) the decrease is 16% from 86 to 74 liters.
using the 16% on the 3m sail decrease it would feel like a 2.5m sail.

i suggest going smaller fins as a potential remedy. I might stay with same center but smaller sides. K4.

this being subjective, in feel .FWIW I had a small sail , kids Superfreak, 3.2 rigged on a 310mast, im a lightweight compared to most pie eaters, these was unreal twitchy. A well developed adult 3.7 on a 340 works much better.

i would be endlessly happy to have your problem. I use the 3.7m only rare. I find a 80 liter is small enough, used a 69liter for awhile, back to 80.

Mark _australia
WA, 19099 posts
22 Apr 2019 10:01AM
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Dropping a board size is very often the remedy, realllyyy overpowered is a combo of board, fin and sail size.
It might be ideal to drop down all 3, but when you can't then dropping 1 or 2 is always going to feel better.

gorgesailor
158 posts
23 Apr 2019 1:56AM
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mthompson156 said..
thanks for the responses, that all makes sense. I am 72kg, and sail in San Francisco.


I am from the SF Bay area & now live in the Gorge. The fact you are asking this question while sailing a 3.0 on an 86liter board at 72kg shows you probably have some technique issues to work out. If you are Sailing in the SF Bay/Delta area, you will never really need a sail smaller than 3.0 at your weight. You are maybe a little on the light side of average. For you to need a sail smaller than 3.0 the wind would have to be gusting to 50knots. a 3.0 should be great for you in 30-40 which is still on the higher side of what you are getting in the bay - even in spring. Any 86liter board is pretty huge for anything more than lightly powered 4.2 conditions IMO. You should definitely have a 70-75liter board for anything from well powered 4.5 down. What kind of sail & board are you on now & where are you mainly sailing?

boardsurfr
WA, 769 posts
23 Apr 2019 3:00AM
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Some years back, I read or heard the advice that going down a board size is practically the same as going down a sail size; the same for going up a size. I find that to generally be true. Since I'm lazy, I often switch boards rather than sails when the wind drops or increases.

In your case, you should definitely go for the smaller board. A +15 liter board like your current 86 is great for lighter wind or if you sail where the wind tends to die suddenly, but that's not what the SF area is known for. In 25+ mph wind and SF/Delta chop, a board that matches your weight will be much easier to control. The net effect will be similar to a using a smaller sail, only better, since sail and board size will be matched, instead of trying to compensate for a too-big board with a too-small sail.

gorgesailor
158 posts
23 Apr 2019 3:55AM
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boardsurfr said..
Some years back, I read or heard the advice that going down a board size is practically the same as going down a sail size; the same for going up a size. I find that to generally be true. Since I'm lazy, I often switch boards rather than sails when the wind drops or increases.

In your case, you should definitely go for the smaller board. A +15 liter board like your current 86 is great for lighter wind or if you sail where the wind tends to die suddenly, but that's not what the SF area is known for. In 25+ mph wind and SF/Delta chop, a board that matches your weight will be much easier to control. The net effect will be similar to a using a smaller sail, only better, since sail and board size will be matched, instead of trying to compensate for a too-big board with a too-small sail.


This is true & especially significant in really windy conditions - it is easier/better to sail a 100liter board with a powered 4.7 than a 85 liter board with a powered 3.0 IMO...

John340
QLD, 1929 posts
23 Apr 2019 1:43PM
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The last time I was less than 80kgs was over 35 years ago. Then I sailed a 70 litre board with 4.2, 4.9 and 5.4 sails. I was never overpowered on the 4.2.

Get the 70 litre board, you'll be fine. If not, just use some more downhall.

Basher
57 posts
26 Apr 2019 7:41AM
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Sorry to be late to this thread. There's a basic lack of analysis here.
Firstly, you have to distinguish between being over-powered and being over-boarded. The former is about the rig and the latter is about the board size with your body weight on it.
Secondly, the above two are both about being out of control, and the third reason when you often feel out of control is when you don't know what you are doing - for example when you are still learning.

Overboarded is when the board is too big in width and volume for your weight, and it tends to be too bouncy for the wave or chop conditions - so it jumps when you don't want it to. And it may also tail ride, with too much lift from the fin. So one solution is then to reduce fin size, and it's easier to change fin than to buy a smaller board.
For sure, another solution is to reduce the board volume or tail width.
So on topic, you might try a smaller, narrower board, for better control but that tboard may also be a bit stop-start if you go too small.

Over-powered is when the rig is not functioning well and that's often because it's badly rigged. If the sail size is simply too big for the wind strength (and best ask first what size sails are other people on?) then changing down a size should help.
But you should be able to feel if your rig is not working well. When overpowered a sail can feel back-handed, with the pull of the sail no longer forwards.

Manuel7
260 posts
26 Apr 2019 10:35PM
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I'm still looking to understand this but I'd say that more than size, it's planing release that plays a factor with sail feel.
A slow to release board will make the sail feel heavier. The opposite is true, a fast to release board will make a sail feel lighter.

For the same board model, the bigger board will float and release earlier.
The smaller board will have better control at the top end.

mthompson156
6 posts
27 Apr 2019 3:28AM
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Basher said..
Sorry to be late to this thread. There's a basic lack of analysis here.
Firstly, you have to distinguish between being over-powered and being over-boarded. The former is about the rig and the latter is about the board size with your body weight on it.
Secondly, the above two are both about being out of control, and the third reason when you often feel out of control is when you don't know what you are doing - for example when you are still learning.

Overboarded is when the board is too big in width and volume for your weight, and it tends to be too bouncy for the wave or chop conditions - so it jumps when you don't want it to. And it may also tail ride, with too much lift from the fin. So one solution is then to reduce fin size, and it's easier to change fin than to buy a smaller board.
For sure, another solution is to reduce the board volume or tail width.
So on topic, you might try a smaller, narrower board, for better control but that tboard may also be a bit stop-start if you go too small.

Over-powered is when the rig is not functioning well and that's often because it's badly rigged. If the sail size is simply too big for the wind strength (and best ask first what size sails are other people on?) then changing down a size should help.
But you should be able to feel if your rig is not working well. When overpowered a sail can feel back-handed, with the pull of the sail no longer forwards.




To clarify: it was blowing 40-60mph and I was heavily overpowered at times. Too much sail. I have sailed 3.0 on that board many times and been very comfortable. This was obviously a much windier situation, and I reckon it's the 3rd time this has happened in recent years. Next time I'd like to be better prepared.

Not really interested in spending a huge pile of money to address the issue since we are probably talking 1-2 days/year max, and usually it's still manageable if a little too powered up (this was the first time I felt dangerously overpowered). I can acquire a smaller board pretty cheaply, though, so that would be worth it if it would solve the problem. Probably just need to borrow a smaller board and try it next time this happens.

Gestalt
QLD, 12061 posts
27 Apr 2019 6:54AM
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a smaller board will make a difference. you could even go down to 65lt in that wind.

50 knots is getting extreme and it becomes very difficult to gybe in swell. tbh a smaller sail helps too. severne make sails that go down to 2m

Manuel7
260 posts
27 Apr 2019 2:53PM
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Smaller fins make a big difference. I would try that first. I sailed 3.7 in 35-55 knots. I occasionally got flattened out and kept traveling upwind but on 77L I was ok. Completed a few jibes and jumps. My skill level was quite limited then (still is :D !). You can also move mast track forward to keep the nose down.

bhc
VIC, 107 posts
27 Apr 2019 8:19PM
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From Jaeger Stone's Red Bull Storm Chase interview in Windsurf magazine:

"I weigh 73 kg and I used my 72-litre Starboard UltraKode on the first day. On the second day, I used my prototype 76-litre Starboard UltraKode which was designed for bigger waves and cross-off winds. In both boards, I used my Stone Surf thruster fin setup with an 18cm rear fin and 11cm side fins. On the first day, I sailed on my Severne 3.3 and 3.6 S-1 Pro and the second day I used my 3.0 custom Severne S-1."

Obviously he's a top pro but still is subject to same laws of physics :). Considering he didn't go smaller than 3.0 sail - Traversa @62kg didn't go below 3.0 either, even when it was gusting to 131km/h, the answer is probably a smaller board... with proper fins.

forceten
655 posts
27 Apr 2019 9:13PM
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bhc said..
From Jaeger Stone's Red Bull Storm Chase interview in Windsurf magazine:

"I weigh 73 kg and I used my 72-litre Starboard UltraKode on the first day. On the second day, I used my prototype 76-litre Starboard UltraKode which was designed for bigger waves and cross-off winds. In both boards, I used my Stone Surf thruster fin setup with an 18cm rear fin and 11cm side fins. On the first day, I sailed on my Severne 3.3 and 3.6 S-1 Pro and the second day I used my 3.0 custom Severne S-1."

Obviously he's a top pro but still is subject to same laws of physics :). Considering he didn't go smaller than 3.0 sail - Traversa @62kg didn't go below 3.0 either, even when it was gusting to 131km/h, the answer is probably a smaller board... with proper fins.


I hesitate to use these 2 as examples , they are over the top on sailing expertise. Which you do state quite well.
you don't mention what size board TT was on, he is usually on a very small one in the 60s for sure.
Smaller fins will aide in control, 18 on Jaegers is large to me, but then

Basher
57 posts
28 Apr 2019 6:22AM
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I'm still not relating to some of the advice given here. We often get very strong wind army home spot and indeed we just a westerly gale blow through here today (in the UK). The biggest sail I saw this afternoon was a 4m.

I think there are three control issues in strong winds:
One is being an experienced windsurfer for those conditions.

The second is to have not just a small sail but one which has a good mast to go with it, and that's a 340 length mast if need be. In strong wind the variations between gusts and lulls are often greater than for more normal wind strengths, and so you really need a rig that works well. It's not just about getting down to a small sail area. Many sailors would rather hang on to a 4m rig they know depowers well, rather than to switch to a 3m or a 3.5 on the wrong mast. Anyone sailing at the PWA event in Pozo each year soon gets to know this.

Board size is another issue when it comes to control in wild weather, but you also have to have enough float under your feet to deal with the longshore currents and white water, plus the wind lulls. The width and tail width of the board also have some say in board control. This issue was perhaps not properly understood until recently. We used to all change down to sinker boards for wild weather but we now know that you can stick on quite a floaty board if it's a multifin, because they don't tend to 'tail walk' like the single fins boards of old used to. That said, you can still overfin a multi fin board and that will show up when the wind is strong. The lighter you are the less fin area you need.
But my main point is that we don't see people using tiny boards nowadays - and indeed boards of 70 litres or less just don't sell.
When you are overboarded then try and look for narrower kit, but not necessarily with less volume. When overfinned, then reduce the length and area of your fins. If your sail feels too big, is that because it's not working on the mast you have?

forceten
655 posts
28 Apr 2019 7:36AM
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Basher said..
I'm still not relating to some of the advice given here. We often get very strong wind army home spot and indeed we just a westerly gale blow through here today (in the UK). The biggest sail I saw this afternoon was a 4m.

I think there are three control issues in strong winds:
One is being an experienced windsurfer for those conditions.

The second is to have not just a small sail but one which has a good mast to go with it, and that's a 340 length mast if need be. In strong wind the variations between gusts and lulls are often greater than for more normal wind strengths, and so you really need a rig that works well. It's not just about getting down to a small sail area. Many sailors would rather hang on to a 4m rig they know depowers well, rather than to switch to a 3m or a 3.5 on the wrong mast. Anyone sailing at the PWA event in Pozo each year soon gets to know this.

Board size is another issue when it comes to control in wild weather, but you also have to have enough float under your feet to deal with the longshore currents and white water, plus the wind lulls. The width and tail width of the board also have some say in board control. This issue was perhaps not properly understood until recently. We used to all change down to sinker boards for wild weather but we now know that you can stick on quite a floaty board if it's a multifin, because they don't tend to 'tail walk' like the single fins boards of old used to. That said, you can still overfin a multi fin board and that will show up when the wind is strong. The lighter you are the less fin area you need.
But my main point is that we don't see people using tiny boards nowadays - and indeed boards of 70 litres or less just don't sell.
When you are overboarded then try and look for narrower kit, but not necessarily with less volume. When overfinned, then reduce the length and area of your fins. If your sail feels too big, is that because it's not working on the mast you have?


A little less la dee dah and maybe actually answer the OP question. Yes clever to suss out a 340 mast works on small sails. So, sailor experience, sail and correct mast, multi fins not too large. No tiny board , umm Because indeed they don't sell , how does that make sense. Any lastly don't get a modern board , but get a narrow board , which is more likely from another era.

Still not relating , funny

bhc
VIC, 107 posts
28 Apr 2019 10:15AM
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forceten said..

bhc said..

you don't mention what size board TT was on, he is usually on a very small one in the 60s for sure.



TT: "I am 62 kg, the board I used was 66L with fins 15/9 set up as a thruster. My sails were GA 3.0m to 3.6m, mostly overpowered!"

forceten
655 posts
28 Apr 2019 9:01PM
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bhc said..

forceten said..


bhc said..


you don't mention what size board TT was on, he is usually on a very small one in the 60s for sure.




TT: "I am 62 kg, the board I used was 66L with fins 15/9 set up as a thruster. My sails were GA 3.0m to 3.6m, mostly overpowered!"


Appreciate that. TT is in a small group, that is both extremely talented and light weight.

Mark _australia
WA, 19099 posts
28 Apr 2019 9:14PM
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Basher- You're not getting it

He basically said I have a 3,. I can't go smaller on the sail, will a smaller board help with the overall feeling of control?

Answer- yes it will

Your essay was correct, but did not address the question..... which was essentially - inability to address one variable. He can't address sail size, conditions and his experience are fixed.


So yes "There's a basic lack of analysis here." as you said. Indeed there is. You wrote volumes about all kinds of stuff but forgot the basic question he asked - I'm already on the smallest sail I can get, will a smaller board feel better? "YES" is the answer.




Analysis of the question which was "Any thoughts on how much smaller a sail will feel when you drop down in board size"
Not "hi can anyone tell me all about high wind theory...?"




Basher
57 posts
29 Apr 2019 4:35AM
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I take your point, but the answers to all these windsurfing questions lie in understanding the bigger picture.
We often think we have one specific problem, when several other things are usually connected.

And, here, it's right to understand the nature of the control issues. If you only have one rig, then how can that rig be made to work better? For sure, that wasn't asked.
And if you can only change down with the board 'size', the question is then what board - and then what board volume, what board width? And, never mind about the board, did you think about fin issues first?
So the answer is: Possibly, but not necessarily.

The other replies were helpful and varied, but often based on a linear view, or on personal response. There's also a discussion about 'drag' which is another whole area of theory, but, if you're talking about drag and board size well you might also talk about rocker and rail shape. And so on.
The great thing about forums, is when everybody pools knowledge and their individual point of view.
You'll have to excuse my approach to things - which is very 'Gestalt'.

I'll shut up now.

forceten
655 posts
29 Apr 2019 4:56AM
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Promise .

bhc
VIC, 107 posts
29 Apr 2019 10:47AM
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I enjoy and find Basher's posts informative. I don't think anybody should be discouraged from putting an effort in an honest post to share their knowledge, experience and point of view. In addition to the simple answer to the OP's question, I've learned a fair bit extra.

forceten
655 posts
29 Apr 2019 9:59PM
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bhc said..
I enjoy and find Basher's posts informative. I don't think anybody should be discouraged from putting an effort in an honest post to share their knowledge, experience and point of view. In addition to the simple answer to the OP's question, I've learned a fair bit extra.


OTOH . Having read SirBasher for over 10 years on the Boards forum, I found that he is very single minded, is quick to point out what your opinion should be, on multi fins, people who build at home, which he calls shed builders with distain. how can a home builder reach the level of mighty Starboard ? He promotes or did Starboard . He never liked Witchcraft and never saw the magic.

Threads go astray from the OP. Sh1T happens.
OTOH I'm pleased you have gained knowledge.
Posting on a forum , within reasonable limits invites a opposing opinion. As you have made your known.
i add very welcome at that



gorgesailor
158 posts
30 Apr 2019 1:30AM
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Problem is the OP has not given more specifics, yet bottom line is a smaller board will help.

Likely rigging & technique tips would too but he hasn't elaborated on the sail/mast or even the exact board let alone any rigging or stance issues so there we are.

forceten
655 posts
30 Apr 2019 3:40AM
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gorgesailor said..
Problem is the OP has not given more specifics, yet bottom line is a smaller board will help.

Likely rigging & technique tips would too but he hasn't elaborated on the sail/mast or even the exact board let alone any rigging or stance issues so there we are.


Yes, he's only stated the sail size and 86literbboard is a thruster.
I felt when I read it and do still that his question is general in nature, perhaps specifically, because he doesn't want to address when someone asks , what color are his harness lines.

So yes your and my bottom line is a smaller board will help.
Problem, I don't see any . At times things aren't more than what they are.



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"Smaller board - difference in sail power" started by mthompson156