View Full Version : Instability while planing
20th March 2008, 03:36 PM
Hi Roger, Hi All,
Weather still a bit cold here on the South coast of England, but getting out a little. I have a rather non-specific question on technique, but hope that I might get a little help and/or suggestions.
I am only starting my second season and whilst I am regularly planing,conditions permitting, once on the plane I loose control very quickly. The board seems to start to " snake " a bit like a speed wobble on a motorbike. This becomes increasingly exaggerated and usually results in an early bath.
I am not yet getting into the straps or harness. I am sailing a Carve 145 with standard 52 cm fin and a range of sails from 5m to 7.8m. I weigh 170 lbs and am 5'6". (Not sure you need this info but thought I would provided it anyway!)
Any thoughts on how to cure this would be most appreciated.
20th March 2008, 03:51 PM
i'm not sure i fully understand the problem (could you elaborate on the speed wobble?) but perhaps part of the problem is that you don't lean back enough or move to the back and side of the board enough. As you are starting your second seaqson i'm wondering: how is your footstrap surfing? Secondly, what conditions do you fly in? Fully overpowered required a different attitude then underpowered or powered up .. Usually when you lose controle you end up going down wind i suppose, you can compensate this by litterly pushing with your feet on the side of the board or better yet by placing the footstraps more outboard and getting in them (the rear ones might be a hassle but once you get it, you're off and i've surfed overpowered out of the rear footstraps aswell with very few problems).
Also a way of controling the speed and the sail is by rather then leaning back in your harness, is to put yourself in a more sitting-like position (show off that bum!), it'll decrease your speed but you'll feel safer and it'll permitt you to move a bit more freely untill you get that hang of your board.
When i first read your thread i was thinking of overfinning: fin = too big, but seeing as you're usuing it with a 7.8 on a 145 L board i doubt it, however, it might be one of the factors why your board is more unstable with smaller sails (my recon 5.0 - 6.7), you migth want to consider like a 48-er or so ... Overfinning can be one reason of losing controle; i once was forced to overfinn and even though i very much enjoyed the speed i got, i was not the smoothest ride i had nor the safest or most confortable.
hope i said nothing wrong, and if so, Roger will correct me, i hope ...
anyway, hope it helps Roly,
20th March 2008, 11:13 PM
Thanks for your thoughts. I am generally talking about 20/25 mph with a little chop. I think your comments about getting further out may help as I have occasionally had that stable feeling of getting far enough back and outboard with pressure against the fin, sort of sideways. I think that I may not be getting into that position quickly enough, particularly as I usually get pulled over the front.
I am a little confused as to how soon I should be going for the front strap and gradually move back into the rear strap. And is this before or after hooking in? I am certain that I need further tuition on this to progress this year.
Thanks again for taking the time to post.
22nd March 2008, 01:45 AM
Roger probably could answer this better, but I'll give a couple tips.
You wrote: "I am not yet getting into the straps or harness." That's the main problem. You are probably standing close to the mast base and trying to control the power of the sail purely by sheeting in and out with your back hand. That's a recipe for exhaustion and getting bounced and catapulted. To sail with control in a lot of wind, especially with a wide board and long fin like you have, you need to be fully committed to the harness and footstraps with your body hiked way the heck out over the water, and the sail leaned to windward like this:
Or as a friend of mine once put it "keep the hammer down".
I have some advice about using the harness and footstraps in this blog post:
There's a couple things you could do to make it easier for yourself. 1) Make sure the footstraps are in the inboard and forward positions where they are easiest to reach. 2) Use a much smaller fin if it's more than 20 mph (about 42 cm) 3) When it's windy put your front foot in the strap right away, even before you are planing, to avoid getting catapulted. With the proper mast-base pressure and your back foot over the centerline of the board you can do this without rounding upwind. 4) When you're planing good with your front foot in the strap, the sail fully sheeted in and your body leaned out over the water, you can get in the back strap. Then, while still "keeping the hammer down", you can thrust your pelvis forward, hook into the harness, and then carefully push the sail away from you with both hands to transfer the power into the harness.
23rd March 2008, 10:50 AM
CC and James have given you some pretty good tips.
I think the real issue here is that somehow you are not moving back on the board,
you are not getting hooked in and in the straps (or at least not at a time that will cause your board to accelerate more) and since you are not placing your weight fully on your harness, you simply aren't getting the required Mast Foot Pressure (MFP) needed to drive your board steadily forward without any "wobbles".
You may think you are fully planing, and in control, but you really are pretty much at the mercy of your rig.
If you sheet in more, it wants to pitch you over the front of the board.....why?
Because you aren't back on the board and in the footstraps where the power in the rig will make you go faster, not go over the front.
I have not said this as much recently as I did a few years ago.
You have to "go through the gears" in the same fashion you would with a manual transmission in a car or motorbike.
First gear is where you get the rig powered up, but you do so carefully so it does not have the ability to throw you around. If you sheet in a little, the rig powers up a little. If that's too much, unsheet (sheet out) a bit and the power will be reduced.
OK, time for 2nd gear.
Now you need to begin to move back on your board slowly and progressively as the boards speed begins to build. You need to stay over the boards centerline so it does not round up or "wobble".
You need to move back at a rate that keeps the board accelerating. Do not try to "accelerate the process" but rather let the speed of the board set the rate at which you move back.
At this stage you are moving your feet back and slowly increasing the pressure on the rig.
OK time for 3rd gear....
Now you will be back far enough on the board, rear foot right over the centerline and behind the front footstraps (do not go too far back and cause the nose of the board to "pop up" andf kill your speed).
If you put all your weight on the rear foot, right over the centerline on the board, the board will continue to accelerate and there should be no wobbles.
Now slide your front foot into the front footstrap.
Once you are comfortable in this position, hook in to your harness.
OK, now it's time to go for 4th gear and get your back foot into the rear footstrap as you continue to rake your rig back and sheet it in progressively more.
The goal here is to continue to keep your board accelerating, and progressively get more and more "mast foot pressure" (MFP) to drive your board forward from the mast foot, not from your legs and down through your body.
In 4th gear your body starts to be "suspended" from your rig and you can begin to lean out and back to get better leverage on the rig.
Any required steering can be done with the legs both pushing/pulling, and "rolling" the rear of the board.
Roll the lee rail down a little and the board will heqad upwind "on the fin".
Roll the lee rail down a lot, and the board will head off pretty drastically like you where initiating a jibe.
Roll the upwind rail down a bit and the board will head upwind, but on the shape in the bottom vs the lift from the fin.
Could be your "speed wobble" is occurring as you roll the board slightly back and forth.
OK, once you get this far, it's time to go for 5th gear and really get the final acceleration.
You now are all the way back and outboard on your board, your rig is raked back until the foot angle is parallel with the top of your board or the surface of the water.
The rig is fully sheeted in. Your weight is suspended off the harness and you are keeping your weight as far from the boom as your arms will reach.
The board is totally being pushed along by MFP.
Do you have any video of you out sailing.
Send me a clip and I can provide much more "to the point" information on what you may be doing that you'd want to change.
My guess would be that you are in the "semi planing" mode (nearly all boards have a bit of a "speed wobble" when semi-planing) and you just need to "shift gears" a bit to get beyound this stage.
Hope this helps,
23rd March 2008, 11:35 PM
Dear James and Roger,
Thank you both for your replies. All very useful. I need to get out there and "feel " what you are suggesting to see the effects. I like the gear changing analogy. It is like a swing thought in golf and will help me remember what I should be doing and when. One of my problems has been when to go for the straps/harness and in which order. I shall adjust my straps into the forward/inboard position for a bit to give me a chance to get the feel perhaps in slightly less windy conditions, what do you think? I have not changed them since I bought the board and they are in the aft/outboard position at present.
I will certainly try to get some footage to post so that more specific comments can be made. I will try to get my wife to do this although she rarely spectates as she finds it rather frightening!
I always appreciate the help and will let you know how I get on.
24th March 2008, 04:49 AM
Hmmmmm.... "One of my problems has been when to go for the straps/harness and in which order. "
OK, this pretty much says it all about your dilemma here.
You seem to think you need to "go for" the footstraps and harness.
When you get everything sorted, it will no longer be something you need to "go for".
You will simply know that you have the speed and stability needed to shift to that next "gear".
Please encourage your wife to snap a photo or 2 (video clips would be even better).
I'm sure that (just like all of us) you've developed some bad habits and you will have no idea (even when you look at them later) what you might be doing that is causing you the issues here.
Hope this helps,
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