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General Category => Foil SUP => Topic started by: SUPdad on February 23, 2020, 10:39:54 PM

Title: Mast position and balance
Post by: SUPdad on February 23, 2020, 10:39:54 PM
Question...why is it so much harder to stand and paddle on my board when I move the mast further forward?  I've been experimenting with mast position last few times out.  Kalama 6' x 28" custom board (bought used so not custom to me), about 115-120 liters, Armstrong 1600 foil and I weigh about 185 lbs. 

My usual spot to mount the foil happens to be right in the middle of the tracks.  I can move it 1/4" forward of the middle and it's still okay.  But once I move it just a little more, maybe 1/2" forward of the middle, the board goes from being easy to stand, balance, and paddle, to being very difficult.  I have a theory or two about why this happens but wondering what you all think.

Title: Re: Mast position and balance
Post by: peterp on February 23, 2020, 11:33:58 PM
The mast position shouldn't affect standing and balance significantly, but if it goes too far forward it starts working like a pivot point and your will have excessive yaw.
Title: Re: Mast position and balance
Post by: Wetstuff on February 24, 2020, 05:59:41 AM
Curious, Dad...  What's your theory?

Jim
Title: Re: Mast position and balance
Post by: Dwight (DW) on February 24, 2020, 07:10:22 AM
That means the tracks are placed exactly right. Ride it in the middle of the tracks.

When developing boards, I keep working the foil forward in the track to find that point where the board loses itís mind. Tracking goes to crap, balance becomes unruly. Not just paddling, but flying is unruly.

Once the point of unbalance is found, I bump the mast back just enough to get out of that weird state, and everything becomes easy again. Typically just a 1/2Ē back from the awful position.

There is so much going on. The board has a natural balance point on the volume distribution, where you have to stand to be able to paddle it. This assumes you are using the minimum size board possible. Not some oversized model where nothing is critical. Then the foil has to placed to work with where you are forced to stand on it. Foil too far forward and it feels like balancing on a pogo stick. Mast too far back and you canít pump it into the air from where you are standing on it. Same with flying. It needs to be under you in the right place when you go airborne.

There is a lot to it. Trust your shaper. Use the middle of the tracks. Donít awesome you know more than him, unless you really do. 
Title: Re: Mast position and balance
Post by: SUPdad on February 24, 2020, 08:51:26 AM
Thanks, glad to hear Iím not going crazy! :o  I have to say, though, that it amazes me that a 1/2Ē makes that much difference.

I guess I should explain why I was moving the mast forward. I saw a post or video somewhere about balancing your foil/board setup where you hang it upside down and find the balance point on the wing chord. When it balances about 25-30% (or wherever the ideal balance point is along the MAC), then the procedure is complete. This should be easy to do on a prone board but not so on a standup. 

I have been trying to learn to pump the foil with not much success. I am completely aware that itís most likely my lack of conditioning and ability that is the problem. ;D However, I started wondering why you donít see very many on a SUP that can. Those that do are on very short boards so more likely to be CG balanced. So anyway, I do believe a setup with a CG that is not ideal, is going to be much harder to pump.

What I learned yesterday after suffering for an hour and a half was that it seems to foil better with the mast way forward. Given it was a small day so no issues with being able to keep the foil down and I did have to move my foot position. Foil seemed more responsive/neutral, maybe a little easier to pump.  In any case, no bad side effects once on a wave.

So my question is now how do you design a board that is easy to stand on and paddle with the mast more forward?  Even if you have to always be moving, with a little more stability, it would be fine for me. With the mast 1/2Ē forward, slow forward speed doesnít help much. Even paddling fast was still quite wobbly for me.  Maybe a skeg behind the mast?  For my board, maybe a little thicker in the nose would add some buoyancy without much swing weight increase?  Maybe itís not just the mast but also the entire foil that needs to be considered. One of my theories is that if the foil is more forward of some point (maybe the combined mass of board and rider?) then itís effects from wind/current have more leverage to knock you off the board. Hard to explain what Iím thinking. ;D

Title: Re: Mast position and balance
Post by: SanoSlatchSup on February 24, 2020, 08:54:53 AM
Agree with much/most of what DW states, but I've also found that individuals' weight to board size ration has a lot to do with it as well...the paddling part that is.

Over the past 5-6 months, I've gone from 207lbs to 185lbs, and notice that I have a much larger area of board that I'm able to stand and paddle from than when I was previously carrying the extra 22lbs on the board.

Previously I had to stand much further forward on the board in order to balance/paddle it than I need to now (mast placement made little difference, but I already knew where my mast worked, and where it didn't on the board. My assumption is that I needed the extra volume of foam in the nose to be in the water to float me, comparatively to what I need now, and can therefore stand rearward more, with more nose out of the water not aiding in floatation.

That's a great setup you have there, and we're paddling the same size boards (mine's a King's) at the same weight, so when you move your mast/foil forward, you may just have to move your standing/paddling position a little forward as well of maintain your balance...just as you would if you were moving the center pivot point on you neighborhood teeter-totter forward or backwards.

Just my couple of theories/guesses.  :)
Title: Re: Mast position and balance
Post by: SUPdad on February 24, 2020, 09:05:57 AM
Yes, I found I was standing a little more forward when paddling around. However, sometimes it felt more stable to stand further back and get the nose out of the water...this required more forward movement though. With my setup, standing more forward, the nose is just above the surface of the water and the board (or maybe itís the foil) kind of plows and itís very easy to pearl when paddling for a wave. I fell so many times yesterday and not your typical foil fall, i.e. the wobble and slow lean and then fall but rather quick out of the blue, where did that come from, falls.  ;D

I think this CG thing is huge, much bigger than we think. I heard about this a while ago and only now have I given it much though.  Perhaps it also explains why you see different sized foils recommended for prone vs SUP.
Title: Re: Mast position and balance
Post by: SanoSlatchSup on February 24, 2020, 09:35:27 AM
I have been trying to learn to pump the foil with not much success. I am completely aware that itís most likely my lack of conditioning and ability that is the problem. ;D However, I started wondering why you donít see very many on a SUP that can. Those that do are on very short boards so more likely to be CG balanced. So anyway, I do believe a setup with a CG that is not ideal, is going to be much harder to pump.

What I learned yesterday after suffering for an hour and a half was that it seems to foil better with the mast way forward. Given it was a small day so no issues with being able to keep the foil down and I did have to move my foot position. Foil seemed more responsive/neutral, maybe a little easier to pump.  In any case, no bad side effects once on a wave.
Ah, the age old try for the Brass Ring of foiling...being able to pump out and connect another wave.  :)

Yeah, "been there, done that" myself, and all I can say is that your wing/board choice is super critical wrt that. I went from the Iwa, and M200 attempts with both the Maliko and Kai tails with little to no success (the Iwa/Kai got me the closest)...to the GL180 and 18N setup, and I'm just figuring out the turn into wave #2 away connecting, and that's with only a couple of sessions under my belt on the new set up.

The foilers pumping out at our locale are either young guys on prone mini potato chip sized boards, or "older" guys (50's+) on smaller boards with high aspect wings...or world class athletes like Chuck Patterson, Thomas "Maximus", or Zane when he was here a year or so ago.

Quote
So my question is now how do you design a board that is easy to stand on and paddle with the mast more forward?  Even if you have to always be moving, with a little more stability, it would be fine for me. With the mast 1/2Ē forward, slow forward speed doesnít help much. Even paddling fast was still quite wobbly for me.  Maybe a skeg behind the mast?
You mean like this?
(https://i.imgur.com/bchPFFR.jpg?1)
Yeah, thought it was the best thing since sliced bread the first couple of times out with it, but then after I forgot to put it on one time, and didn't realize it for a couple sessions until I went to show someone else how cool it was...did I realize the it made no difference one way of the other...besides maybe being a mental thing, that since I had it on it must be easier to paddle straight. Dunno, other than I didn't/don't need it.

Quote
For my board, maybe a little thicker in the nose would add some buoyancy without much swing weight increase?  Maybe itís not just the mast but also the entire foil that needs to be considered. One of my theories is that if the foil is more forward of some point (maybe the combined mass of board and rider?) then itís effects from wind/current have more leverage to knock you off the board. Hard to explain what Iím thinking. ;D
The other thing that seems to help me paddle straighter, is that I have concaves that run the entire length of my board that I feel help channel the water under my board compared to my first board design that was completely flat on the bottom (like the Kalama boards)....
(https://i.imgur.com/Zej7H9i.jpg?1) (https://i.imgur.com/sE2fKkm.jpg?1)
...as well as gets air under them faster which helps with initial lift as it breaks the water tension quicker (in theory anyway :) ).
Title: Re: Mast position and balance
Post by: SUPdad on February 24, 2020, 10:46:49 AM
Itís not the paddling straight thatís a problem for me at the moment. I can deal with the yaw, although it can be annoying. Itís the stability thing that is tough to deal with. Iím not sure if this is something you get used to or not.

Iíd imagine the angled foil makes the CG thing worse?  Iím not really familiar with your setup but thinking if the tracks and mast are more forward, this would tend to make the CG move forward?  I almost think if the mast were angled back it would be better overall?  CG could be optimized more easily. Since the skeg didnít help you, maybe itís the foil itself and not so much the mast that affects stability?

I really wish I could understand why stability goes down when the foil is moved forward.
Title: Re: Mast position and balance
Post by: Dwight (DW) on February 24, 2020, 11:30:32 AM
SupDad Iím your weight. I never paddled back out with my 5í11 and 1600 sq cm setup.

When I went to a 5í8 and 2000 sq cm foil, all of sudden could do it and I thought oh shit! Itís gear, not my old age.



Title: Re: Mast position and balance
Post by: PonoBill on February 24, 2020, 11:31:33 AM
I don't understand the CG theory at all. The center of gravity of the board with the surfer on it can be radically different from a static measurement of the board and foil--the rider weighs perhaps five to ten times more than the board and foil
Title: Re: Mast position and balance
Post by: SUPdad on February 24, 2020, 11:52:30 AM
The CG theory is not the combined CG of equipment and rider. Rather, itís centering the mass of the board/foil over the CG of the wing itself. The wing wants to pivot in pitch around its CG point. If the long overhang if a typical SUP board is forcing to pitch the wing down, the riderís weight must counter this. All fine when foiling in a steady state. But if you wish to change the pitch on the wing (nose up), more weight shift is needed compared to a short prone board setup. If you could mount the mass of a longer, heavier SUP board so it was centered over the wingís CG, it would be more responsive, and easier to pump. Of course, where the mass is centered exactly is dependent on the wing (and being able to figure out/guess where itís CG point is) and also mast length. Iím no engineer and struggle to explain this stuff but I believe thereís good reason to consider this.
Title: Re: Mast position and balance
Post by: SUPdad on February 24, 2020, 11:58:41 AM
SupDad Iím your weight. I never paddled back out with my 5í11 and 1600 sq cm setup.

When I went to a 5í8 and 2000 sq cm foil, all of sudden could do it and I thought oh shit! Itís gear, not my old age.

I believe as the board size gets under 6í it starts to become easier to get it CG balanced. Iím ready for a shorter board but still need about 120 liters of volume. I was considering a Kalama production board as thereís one size thatís perfect for me. However, not Iím not so sure. And I still want to know why itís so damned hard to balance on my board when the mast is too far forward.  ;D
Title: Re: Mast position and balance
Post by: jondrums on February 24, 2020, 11:11:48 PM
I'm no expert on pumping.  That said, I'm thinking that the CG of the board has an ideal location with respect to the foil center of effort and pitching moment center. That's because at the critical part of the pump where the board is unweighted, it needs to pitch up slightly and gain height through lift.  If the CG is in the wrong place, I guess the rider has to weight the board a bit to compensate which would make it harder to gain the height needed.

Title: Re: Mast position and balance
Post by: SUPdad on February 24, 2020, 11:27:28 PM
Thatís my thinking exactly...thanks for explaining it more clearly. So now how to design a board that is more balanced and not so nose heavy?  I know most of the prone guys who pump themselves all over the place are younger and in much better condition than I am but still they must have a big advantage with the lower weight board and also being more balanced. Someone needs to figure this out! ;D
Title: Re: Mast position and balance
Post by: SUPdad on February 24, 2020, 11:30:19 PM
SupDad Iím your weight. I never paddled back out with my 5í11 and 1600 sq cm setup.

When I went to a 5í8 and 2000 sq cm foil, all of sudden could do it and I thought oh shit! Itís gear, not my old age.

Did you happen to compare the relative position of the bigger wing vs the smaller?  Would really like to see the difference in balance point between both setups.
Title: Re: Mast position and balance
Post by: surfcowboy on February 25, 2020, 07:21:18 AM
Iím interested in this idea. But there are clearly exceptions.

This Maui guy at 1:30 in this video ruins our discussion.

https://youtu.be/gBvQe02LoFk

But a lot of the Kalama boards look like theyíd balance like youíre saying.

I also think thereís more to volume distribution than the non shapers on here see. Iím about to start making some exceedingly dumb SUP foil boards and will report back on them as I iterate. SUP seems to require the volume to shift rearward from my casual investigations (both Kalama and BluePlanet do this, not sure about DW but out of respect for trade secrets I wonít even ask.). But then that dude pumps by like a champ on what looks like a stock SUP and blows all my ideas away. lol

But thanks for this topic. Itís how we all learn and as usual, there is gold hidden in these threads.
Title: Re: Mast position and balance
Post by: SanoSlatchSup on February 25, 2020, 09:33:50 AM
Iím interested in this idea. But there are clearly exceptions.

This Maui guy at 1:30 in this video ruins our discussion.

https://youtu.be/gBvQe02LoFk
The guy at 1:30 wasn't pumping back out, he was pumping w/ the swell energy to stay ahead of it which is much easier to do on any size board. It's pumping back out against the swell that's the real challenge that so many on the larger SUP boards struggle with.
Title: Re: Mast position and balance
Post by: SUPdad on February 25, 2020, 11:54:26 PM
Very small day but I went out and had the mast where it was last time. Seemed easier to balance and paddle around this time. Maybe itís something you get used to after a while?  Anyway, seems like steps in the right direction. Next time out, the mast will go all the way forward.
Title: Re: Mast position and balance
Post by: surfcowboy on February 26, 2020, 01:05:19 PM
SanO, good catch. Yes, he had ďhelpĒ in that pump.

By the way, how casual does he look? Love his style.
Title: Re: Mast position and balance
Post by: SUPdad on February 28, 2020, 10:48:31 AM
So Iíve been moving the mast forward and trying to draw some conclusions. One thing that Iíve noticed is that balance when standing/paddling has become easier. I guess you get used to it after a few tries. Iím also thinking that pumping, or at least my attempts, are working better.

Yesterday, I moved the mast all the way forward in the tracks. Balance was okay, pumping feel was okay. Conditions sucked so not too sure about how it feels riding a decent wave. Itís been very small, weak and windy here lately. Board feels weird when paddling for a wave, like it wants to pearl. Not sure if my foot position is different (thinking that I need to stand more forward) or if the board just isnít designed to have the foil that far forward.

Unsure, really, where on the chord the setup should balance at. Just guessing but I think itís close to ideal but still maybe a little nose heavy.
Title: Re: Mast position and balance
Post by: jondrums on February 28, 2020, 11:10:09 AM
it would make sense if your foil is all the way forward, then you'd have to stand further forward on the board - this would tend to make the board want to pearl before you're up to speed.
Title: Re: Mast position and balance
Post by: SUPdad on February 28, 2020, 03:18:42 PM
Very true but if feels more like the foil is pushing the nose down into the water. Of course, this is just my perception and is probably incorrect. ;D
Title: Re: Mast position and balance
Post by: PonoBill on February 29, 2020, 02:30:46 PM
That's Fares at 1:30, and he can indeed pump that clumsy-looking board back out. It helps that he's very light and experienced. That board isn't quite as big as it looks, he's short.
Title: Re: Mast position and balance
Post by: surfcowboy on February 29, 2020, 03:28:01 PM
He is my spirit animal.