Foils – sailrepair.co.uk

Posted on July 2, 2024 by John Blackwell — Leave a comment

Patrik Aeon Foil

Real world windfoil choices.

Below are my thoughts on windfoil choices for the real world conditions most of us sail in. This is written about the Patrik Aeon foil but a lot of it will be applicable to other foils.

Why am I doing this? There is already a lot of information online about ideal foil set up but I find most of what is written is aimed at racing. I don’t race but I do like going as quick as possible especially in light winds. I also want maximum control in gusty strong winds. I do most of my foiling in a sea loch on the west coast of Scotland. The water is surrounded on three sides by mountains so it can be gusty to say the least. We also get squally winds coming off the Atlantic so 10 to 25 kt wind range is not unusual. While these conditions can be demanding they do mean you can test things very quickly as the chances of being both under and over powered in a ten minute period are quite high.

My drive at home can get a bit busy if the wind is up and down

Light winds 6- 10 kts

95s mast + V1 TI fuselage – I use this mast because it is the thinnest and therefore the most efficient and light winds are all about efficiency. Whatever rear wing (stab) I use it is set in the rearmost position for maximum stability. I always use the +1’ shim as I find that works fine on both sizes of stab and on both my fuselages.

On a general note – I always use the 190 stab with the 750 and 900 front wings and the 160 stab with 650 and smaller front wings.

The board will always be a Patrik Foil Comp 85, sail a Patrik S2 8.4 or 7.8 meter.

Choice of front wing for light winds? A lot is written about what the PWA sailors are using but I am not racing. If I look at the water and I can see some gusts of maybe 7 kts but between the gusts the wind looks more like 5 kts then maybe I will go with the 900 wing with the aim to get flying in one gust and then manage to fly to the next gust and gybe in that to try to keep flying. The larger wings help to keep sustained flight. If the gusts are 8+ kts then maybe I will go with the 650 front wing which will give me more speed and I can still get through the light patches of wind but I will need to find another windier patch to fly round in a gybe.

To try to quantify things, I would say I need to get the board moving at about 5kts to take off with the 900 wing and about the same with the 750 wing. The difference being the larger wing can take off in a shorter distance which is useful if the gust is only 15 meters wide and you have to take off in that space. The 650 wing needs the board to be wound up to about 8kts board speed. That is possible in say 8 kts of wind but you need to consider the size of the windy patches and how smooth the water is. These are the sort of things I find no one is talking about and are quite important. Maybe you have read that some great racer can get his board flying in 6 kts with an 8.4 sail so you take yourself off to your local lake to do the same. But the wind is onshore and the small chop is bouncing back off a wall creating a nasty short chop, you will then find it very hard to get the board up to take off speed. You can get a similar situation on the open sea where you can only get flying in one direction because the other direction you are trying to take off directly into the waves and you just can’t build the speed up. Whereas in the other direction you can get the board on the downslope of a wave and use it for a bit of a push.

Whether you are using a 9.0 or 7.5 meter sail for your light wind foiling the thing is having enough wind to pump against. If you give your rig a quick pump you will quickly know if there is any power there for you to use to build up to take off speed.

Medium winds 10 -18 kt

95s mast – for maximum efficiency

100 XL mast – if the sea state is getting higher and I think “longer the better”.

Fuselage V1 so that I can get maximum lift from the front wing. But sometimes V2. The V2 fuselage puts the front wing about 2cm further back. The end result is similar to if you moved all your footstraps 2 holes forward. In effect it tames things down a bit. I use the V2 fuse if the wind is offshore when I need as much range out of the foil as possible.

Board will be a Patrik Foil Comp 85 or 78 or even a Patrik foil move 105. Sail – Patrik S2 7.8, 7.2, 6.6 or maybe a big wave sail if I am traveling somewhere with limited kit.

This is when things start to get a bit more diverse. In light winds efficiency is the goal which mirrors what any racer would be trying to achieve. But in 15 kts of wind there can be a divergence of interests.

If the water is flat and I feel like it I may choose to keep to the efficiency principles of a largish sail and a small front wing on the V1 fuselage so that I can go as fast as I can (I am not a fast foiler, but what I mean is “fast for me”)

So I would be on the 95s mast, v1 fuse, 650 or 450 front wing and 160 stab. Sail wise would be 7.2 or 7.8.

BUT there are days with flat water when I don’t want to be going fast! Why? Because we can get days in the summer when there are big rafts of seaweed floating about or days in the winter after storms when there are lots of things in the water. Times like that require more or a cruisey attitude and I might use the 750 front wing and a slightly smaller sail.

On more open water 15 kts of wind can make the water anything but flat. And maybe trying to race across 1m high chop requires a bravery I left behind some years ago. In such conditions I would go for the longer 100 mast and perhaps the V2 fuselage and then choose between the 650 and 750 front wing.

Strong winds 18 – 30 kts

Both masts are still applicable but I would err towards the longer 100 mast.

Fuselage – V2

Board – Patrik Foil comp 78 or Patrik Foil move

Sails – patrik GTS foil 5.8 or Patrik ride foil 5.4 or wave sail down to very small.

Front wings 750, 650 or 450

I can hear you think “750 is a light wind wing” but above a certain wind strength I often find myself going back towards larger wings. Yes, there is the race philosophy of more wind = smaller wings and there is some logic to that but I will explain why it often doesn’t work for me. Again I need to emphasize I’m not racing, just looking to enjoy myself on the water. While some people are lucky and sail in places that can have steady strong winds, unfortunately I am not so lucky and a windy day may see the wind varying between 15 and 40 kts.

Small wings and sails – small wings need a fast water flow over them to enable them to fly. That in turns requires a constant drive from the rig. In effect it doesn’t matter if the drive comes from a 8.5 meter sail in 10kts of wind or a 3.5 meter sail in 30 kts the pressure is similar. That is why the PWA sailors can use very small front wings in only moderate winds and it is often easier to provide steady drive into the foil with a big rig in a moderate wind. Compare that to when you are out flying happily in 20 kts of wind and a rain squall suddenly puts the wind up to 30+ kts. The usual solution is to ease off and sheet out a bit but small front wings don’t really like that and you can find your session becomes very stop/start.

Linked to what I have said above is the type of sail you use. Foil race sails with all their cams and forced draft/shape in the sail provide a very constant power source. They are great and a definite bonus towards level flight in gusty conditions and are able to fly through holes in the wind better than anything else. But what happens when you become overpowered? You can’t help but sheet out a bit and the sail will then provide “half power”, you can’t completely switch the power off. You have to hide the sail when entering gybes but you can certainly still have a good session. If the wind picks up further then it becomes very uncomfortable. A rotational foil sail may lack the grunt for the earliest of take off but can be a pleasant sail even in lighter winds. In strong winds when you have to sheet right out suddenly you have no power at all. If you are quick you can keep flying by using short pulses of power but generally you will find it hard to maintain flight on a small front wing. It comes down to personal choice and what sails you are using but don’t always follow the mantra of the windier it is the smaller the front wing you must use.

On my foil move 105 I only use front wings from 650 upwards and will use a smaller sail. I also move the rear wing forward to give quicker height control which is useful when the waves are getting bigger.

Summary

There are many ways you can look at the relationship between front wing size, sail size and wind strength. Here are some of my thoughts on the matter.

In light winds I can get flying in 10m on the 750 or 900 wing, with the 650 I might be puming for over 50m to wind up to take off speed so bare that in mind if you are sailing on a small lake where the gusts are the size of a tennis court. Small wings and early flight lend themselves more towards places where the patches of stronger wind are the size of a football pitch.

In moderate winds – if you have enough wind to easily waterstart you should have enough wind to keep a small foil wing going. I don’t think it matters if your power source is 4 or 8m as long as it is powerful enough to waterstart.

In strong winds remember you can be a hero and chase 30+ kts but you can also go on a bigger wing and smaller sail and gybe away until your heart’s content.

I am 95kg, 59 years old with a mental age of 18. .

Posted on October 20, 2022April 26, 2023 by John Blackwell — 8 Comments

AFS 2022 Windfoils

AFS 2022 Windfoils

I have been on AFS foils for many years starting with the AFS2 which then became the Wind range, W85, W95 and W105. They all had the cigar shaped fuselage which from memory was 88cm long. The “W” range was then updated with longer 94.5cm rectangular fuselages and a moulded in collar at the tuttle head. And now we have another development in the new 105cm fuselage. Here I will give my thoughts on the progression. This is not a finished article as I am still testing combinations and set ups and I will update this blog in due course.

I should state that I don’t race so my findings relate to comparisons with previous AFS foils and the occasions when foiling with other sailors. One of the things I have always liked about AFS foils has been their “plug & play” nature. There was never any need to shim things, you could choose what wing size you needed, put your foil together and go sailing. Those days are now passed and you now need to do some trimming.

There are now basically two stabilizer (rear) wings and they have been designed to work on the 94.5cm fuse. So if you are using a W95 with the 94.5cm fuse you can just bolt on the stab without any shimming and go sailing. But when you put them on the 105 fuse they require a bit of negative shimming. The foils come with a couple of AFS shims which are just like flakes of carbonfiber. I have ended up putting both under the rear screw of the stab. I am not sure what angle difference that relates to in degrees. But I have since bought a shim kit from https://www.ap3dcustom.com/products/ and I tried to translate the two AFS shims to the AP3 shim which I think is about -0.5’ and I have now moved onto the -0.4’ shim with the 200 stab. Sorry if this all sounds a bit complex compared to the “fit and forget” AFS foils from the past so let me continue in more of a review style.

I got a W95 with a dismountable fuse and a W100 (new 100 mast height) with the new fixed 105 fuse. I have had them a while and used them a lot. To go with the new T bars I have 900, 700 and 560 front wings and 240 and 200 stabs. I also have a cut down V3 stab.

When I got the new foils it was windy and I used the W100 with the 700 wing and 240 stab (unshimmed) and I was amazed at the amount of lift provided. It felt like it had a similar range to my old R810 wing on the 94.5cm fuse. I am heavy at 95kg and in the past with the 700 wing I had to come out of gybes fast to remain flying and I needed more wind to get flying. But with the extra leverage of the 105 fuse the 700 wing flew much earlier and had more glide. Not quite as early as the R810 but close. Also when you run out of power the R810 tended to just glide down to a stop where as with the smaller 700 wing it tends to be a bit more of an abrupt drop (and the 560 even more so). Anyway those first few sessions felt great but with hindsight probably the 240 stab was doing too much work and I think I would have run into control issues as the speed increased.

Finally a day came when I could try the 900 wing with the 240 fuse. I was really looking forward to seeing how early it would fly. It was a patchy 3 to 8 kts so I had to wait for the gusts to get flying and then see how long I could stay in the air for. I would not like to put a number on what wind speed I could get flying in but it was the lightest I had flown in. So after what felt like a successful session I headed in and a slightly stronger guse came but probably only 10 kts. The foil accelerated and accelerated and the height came up and up regardless of my efforts to pin it down until the inevitable crash happened. I have never had that happen in such light winds before. That experience prompted a chat with Kevin Ellway the AFS foil designer and he advised sticking with the 200 stab on the 105 fuse. So I tried the 900/200 wings and it worked well but at times it felt like I was getting “weed strikes” – strange “slooshing” and “glugging” sounds and sensations. A further conversation with Kevin and he said I needed to add a negative shim to the stab to reduce its angle. I have done that and have had no further issues when using the 900, 700 and 560 front wings.

The new longer fuse certainly increases the lift from the foil. It lets you use a smaller (faster) wing in the same conditions. So by comparison the 700 wing on the 105 fuse is very similar to the 900 wing on the 94.5 fuse and likewise the 560 wing on the 105 fuse is similar to the 700 wing on the 94.5 fuse. When I say similar I mean in broad terms of wind/flight range. The fizzle out when the wind drops is a bit different in that the smaller wings slow down then just drop whereas the larger wing will keep going a bit more.

The same stiffness of previous foils remains. The new 105 fuse has a small tail stabilizer on it. You do need to be aware of it if you are in the habit of resting your feet on the fuse when waiting to waterstart as it is quite sharp and could easily cut you foot.

The dismountable fuselage option on the W95 seems robust. I have been told that the fixed fuse version is going to be the standard and that the dismountable version can be pre ordered. I wanted the dismountable version for air travel. I believe that AFS is now the only fully carbon windfoil on the market which for someone like me who likes to keep his foil bolted together all the time is an important feature.

Here is a video of the W95 with the 900 wing in 9 to 13 kts – https://youtu.be/6uWdSjy1lmU

UPDATE

I have used the foils a lot now and a few things have come to light.

The W100 with the 200 rear wing does benefit from adding a negative shim on the stabilizer. I have found that a -0.5′ shim tends to give the foil more stability across a wide range of use. Without it the lift ramps up a bit too quickly as you go faster.

Posted on March 19, 2021October 7, 2022 by John Blackwell — 2 Comments

Severne Turbo for windfoiling

Severne Turbo Sails for foiling

Introduction – The Turbo GT is Severne’s 2 cam freerace range and is a popular sail for powering fast freeride boards. It lacks the down force to pin down a dedicated slalom board but more than makes up for this by it’s easy nature. The Turbos sit between the no cam ncx which despite not having any camber inducers actually feels more slalom like than the turbo and the NCX can provide the necessary mast foot pressure to make sure a slalom board behaves itself. On the other side of the Turbo is the Overdrive which is a dedicated blasting sail. It has a wider sleeve, more battens and more cams than the turbo but most importantly it has a much more open leech. To compare the sails the size up in the Overdrive has a similar wind range to that of the Turbo for example a 7.8 Overdrive you can use in the same wind as a 7.0 Turbo.

I can’t really start with “first impressions” like I normally do with other bits of kit since I have been using Turbos for a number of years now. So I will simply describe the sails. The Turbos are a bit different compared with most other twin cam sails in that both cams are below the boom. Other sails such as the NP V8 and simmer all have a cam above and below the boom. The result is that the Turbos are probably one of the easiest rotating sails on the market, What is more is that the rotation remains constant across a wide range of downhaul settings this allows you to rig the sails with less downhaul allowing for a tighter leech but maintaining good rotation. This is one of the key factors that makes the Turbos such nice sails to foil with. Up until 2021 the sails from 6.5 downwards had only one cam and 5 battens but the new sails maintain the 6 batten 2 cam layout across all sizes. Other notable points about the sails is that the sails can be rigged on rdm or sdm masts. The 7.0 upwards are supplied with SDM cams and the small sails are supplied with rdm cams. Either type of cam can be purchased as an optional extra and they are easy to change. The cams sit on spacers so fine tuning is straight forward. The sails come with additional spacers although I have to say over the ten or so sails I have used I have not once felt the need to alter the settings of the cams despite using the sails on Maverx masts. Talking of masts the 7.0 is about the biggest sail you can rig on a 430 and likewise the 8.6 actually works better on a 460 than the 490 that is recommended. At this stage I should say that the luff dimensions are often stated. I often find myself rigging the sails with 2 to 4cm less extension than it says on the sails. I tend to look at the mast sleeve as I downhaul the sail. I downhaul until the batten above the boom is just starting to flatten at the mast sleeve. The booms are also relatively compact. While it might be tempting to reduce the outhaul to gain more power I think it is best to keep some outhaul on the sail to maintain a slightly more efficient profile.

On the water – Before you get the sails on the water you may well notice that these sails are light for their size. In use the sails respond well to pumping. There is no need to try to do big pumps, smaller higher frequency pumps tend to work better. The head of the sail should have some spring in it and you want to use that to build momentum in the sail. The result is that you should be able to get flying in a bit less wind than you would with a looser leeched sail. In flight the Turbo will provide a steady power source, feeling light in the hands. When flying through holes in the wind the sail holds its shape and maintains drive. This is where camber inducers have an edge over rotational sails by maintaining drive as the wind pressure drops. In over powered situations the sails can spill power quite easily by sheeting out just a few degrees. When gybing the sails rotate easily and normally do not require any additional pumps of the sail to get the battens to rotate and as such the turbos help maintain flight as you exit the gybe.

Conclusion – It is as if the Turbos really were designed for real world foiling. They might not fly quite as early as some of the dedicated freeride foil sails but what you get in return is a sail that will cover a wider wind range. The sails are best suited to freeride/freerace style foils boards and will suit foils with low to high aspect wings.

6.5 turbo in action – https://youtu.be/6uWdSjy1lmU

Posted on February 19, 2021February 20, 2021 by John Blackwell — Leave a comment

AFS 2021 Windfoils

AFS Wind Foils

I have been using AFS wind foils for some years now so I thought I would give you my impressions of the latest 2021 versions.

I used to use a W105 foil with the R1000 wings and that has been replaced like for like. The R1000 wing has been renamed R810 as the wings are now named by their surface area rather than their wingspan. The new wings will fit on older fuselages but the 2020 wings will not not on the wider 2021 fuselages (apart from on the w85 which is unchanged). The new flange at the top of the mast is now built in and much stronger. The graphics are built in which again is an improvement.

So would I notice any difference with the new foils claiming to be stiffer? Yes, there is a difference but you won’t start flying and say “wow this feels a lot stiffer” what I found is that with the older foils there must have been some increased flex that gave you a sense of height ie you were aware when flying at near full height but at first on the new foils I often found myself flying at full mast height without realising it. The flight feels the same whether you are 10cm or 100 cm above the water. The new fuselages are a few cm longer and if you thought the old foils gave a very level flight the new ones do even more so.

I don’t race so I can’t comment on comparative upwind ability etc but will say I can point as high as I wish.

I had the old W95 which was used mainly in stronger winds on narrower boards with a f800 wing. This has been replaced by the new W95 with either the R810 or R660 wings. The F800 (now renamed the F1080) is not available for the W95 or W105 so I was at a bit of a loss with what to replace it with. I was slightly nervous that the R610 would be tiny and would be a very on/off type foil making life hard work in the gusty winds I often go out in but it is working well. I use the R810 with sails down to 5.3 and winds up to maybe a 25 kt gust. And then the R610 for the 5.3 and below and if the wind is over 20 kts. Even with its small surface area the R610 keeps going through lulls and round gybes etc (i am 95kg).

The new foils come with shims. They have a shim for the front wing in case you find your board flies very nose up or down and then a second shim for the rear wing for you to increase or decrease lift. I am pleased to say I have not used the shims and the foils retain that “plug and play” nature of the older AFS foils, no need to go messing about with settings.

I have used the R810 race wings for a couple of years now, despite their name they are very easy to use. They feel slippy and efficient through the water. To get flying they accelerate easily and don’t need much in the way of pumping downwards. You are best to concentrate on building speed through pumping the sail. When it is windy there is no need to pump at all and you can use the nearest bit of chop as a take off ramp. When the wind drops very light you can keep flying by pumping the sail, small high frequency pumps working the best. The only down side I can think of for using the race wings for learning is that they are very fine tipped so you don’t want to run it aground or kick it. The wings are very tough but with such a good product it deserves to be looked after.

I should point out that while the wings have a “race” label you don’t have to sail them from a outboard stance, the wings are very well mannered and can be sailed in a relaxed upright style with your back foot on top of the front foil bolt, in fact that is how I use them most of the time.

So in conclusion I am very happy with the new foils. I thought I would have to move my footstrap positions to maintain balance but the new foils have worked fine with the straps in the same positions I used for the earlier AFS foils.