mast length

Foiling related talk in here
Sailrepair
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mast length

Post by Sailrepair » Sat Mar 09, 2019 5:54 pm

Here is my own obsevations on foil mast length. This is for freeride/race style foils.

I started out on a pryde alu foil and then a AFS2 foil both with 85cm masts. Then I changed up to a AFS W95 (95cm mast), I still have that foil but also now have a AFS W105 which as its name suggests has a 105 mast. They have had virtually the same wings for all three mast lengths so my comments are aimed solely at mast length.

When I changed from 85 to 95 I initially got caught off balance a few times with resultant crashes. It seemed just like you would imagine the higher you are balancing on something the more sensitive it is. But after a few sessions I got used to it. it felt a bit higher when foiling at near full height but not shockingly so. At that stage gybes were scary on any foil. The longer mast did help navigate choppy water a bit better, helping keep the board clear of the tops of the chop without risking over foiling but again the difference isn't huge. When you think about it compared to the water surface 10cm is "neither here nor there". I think the 95 mast did fly a touch earlier, maybe due to deeper water being more dense.

So onwards and upwards to the 105 mast. Again compared to a 95cm mast the difference is not huge with the foil (same wings remember) feeling familiar. I can tell the difference gybeing in that a 105 foil is a lot of carbon pushing through the water. Initially I was gybing at the same height as I had always done in past and while not greatly different it felt a bit harder to keep flying round the gybe. Now I gybe a bit higher and now it feels like the 105 mast carries on flying as well as the shorter masts. It does feel high when at full mast on the 105. And it does help when navigating choppy water. Today I was foiling off the sea front at high tide where the waves were bouncing back off the sea wall + there was a second wave direction for good measure. The resulting slop is virtually unsailable on normal kit but with the 105 mast I was able to fly above the confusion and had a reasonable session.

So in summary of the performance - there are definite differences just as you would imagine but the differences are not great.

Other factors-

Yes the taller your mast the less likely you are to over foil if you aim to fly at half mast. BUT over foiling on a tall mast is more dramatic since you have further to fall. So the increased drop from over foiling virtually negates the advantage of over foiling less. Obviously if you were racing then you want to keep clear of the wave tops so the longer mast is a advantage.For those getting to grips with foiling or of a nervous disposition the advantages of a longer mast has to be questioned.

Depth - Obviously you need deeper water for a longer mast. That might make no difference to you or it could rule out longer masts. I sail off stony beaches and I definitely don't want my foil touching the bottom so with a 95 mast I wade out until the water is up to the chest zip on my wetsuit (I am 6'2") but the 105 I go out until my shoulders are beginning to be covered which = swimming. At home its no big deal as I only have to go out about 20 yards but if I go to the main sea front at low tide it feel like a long wade out even with the 95 mast.

Strength - a longer mast will put more strain on your board.

So there is my take on mast lengths.

Duncan Adam
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Re: mast length

Post by Duncan Adam » Sat Apr 06, 2019 1:50 pm

I'm still getting used to my ASF 85 with the standard wings, for freeride purposes.

I don't think I would look to get a longer mast but maybe the bigger front wing.

maker
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Re: mast length

Post by maker » Sat Apr 06, 2019 1:58 pm

Sailrepair - you have 85, 95, 105 masts and thanks for saying how performance changes. Whch is your 'go to' one?

Sailrepair
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Re: mast length

Post by Sailrepair » Sat Apr 06, 2019 9:10 pm

I have now also had a go on a 70cm mast (naish).

If it is deep enough I love my 105.

So to add to what I have already said-

A board with 70 cm mast attached is noticeably easier to carry/maneuver on the beach. By comparison with the taller foils it feels like you are doing a lot of chop skimming.

Duncan - the 800 wing for your foil makes a big difference. At first I thought it would be a case of "big sail = big wing" but I use the F800 all the time. The bigger wing sort of fills in the holes in the wind.

Richarli
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Re: mast length

Post by Richarli » Sun Apr 07, 2019 1:42 pm

Excuse the ignorance. Is 800 the width or the surface area?

Sailrepair
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Re: mast length

Post by Sailrepair » Sun Apr 07, 2019 2:56 pm

Sorry, I was saying to Duncan that replacing his 700 front wing with the 800 makes a big difference.

Richarli
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Re: mast length

Post by Richarli » Sun Apr 07, 2019 6:35 pm

Yes understand that but the question still stands. Is 800 versus 700 wing width or wing surface area?
Many thanks

Sailrepair
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Re: mast length

Post by Sailrepair » Sun Apr 07, 2019 9:20 pm

Oh. It is wingspan. The 700 is 779 cm2 and the 800 is 1120 cm2

maker
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Re: mast length

Post by maker » Mon Apr 08, 2019 8:36 am

I guess eventually as wind picks up you get so much lift you cannot counterbalance it so do you keep large foil and get a smaller sail?

Sailrepair
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Re: mast length

Post by Sailrepair » Mon Apr 08, 2019 10:33 am

The AFS foils don't have any adjustment so they fly neutral ie left to its own devices it will fly level. Obviously the board has to be set up to do the same. So my board flies level whether it is blowing 10 kts or 20 kts with the same wing. Flying in a straight line is no problem. ultimately the larger wing will start to argue with me when gybing but that is because I am overpowered rather than the actual wind strength.

If dithering between sail sizes you can choose the smaller sail if you have the bigger wing but You don't need to rig smaller just because you have the bigger wing.

If either through questionable board set up or you haven't quite got the muscle memory for level flight yet so you are having to make bigger height corrections then the bigger wing will require you to be more forceful in your corrections.

So if you have everything set for level flight you can use a 8.5 or a 5.0 in 8 or 25 kts with the only change required being to move the mast foot 4cm forward to balance for a smaller lighter rig.

Problems can arise if you have a board that is too eager to fly ie if the majority of your height correction are to keep it from over foiling then using a bigger wing will give you bigger problems.

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