F4 Race and Slalom Foil Sets 2021. Long Review

I have recently sold off my 3rd foil set for the latest 2021 F4 Foil Racing and Slalom bundles. I started foiling with a SlingShot for easy sailing, advanced to AFS for speed, switched to Starboard for stability and now to F4, seeking a triple threat! I promised myself that I will keep the F4 wings for more than a year!


With COVID restrictions still widespread, shops finding it hard to get stock in and a general lack of gear around I thought I would share some of the details around my new F4 Foils after just a few sessions.

F4 have a long history of making fast formula fins back when demand was higher than supply. Since then they expanded into slalom fins and then helped explore the possibilities of foiling with a range of kite, windsurfing and wind wing foils. They also have a long track record of making fast foils, with riders such as Antoine, Tatty and another 8 or so team riders helping develop the product.

The design philosophy is a blend between my earlier AFS foils and last years ride on Starboard models. F4 claim to have the stiffest masts, born out of the difficult San Francisco Bay conditions where the cross chop can be trying. My limited experience bears this out and a few runs downwind through boat wash or chop have been noticeably smooth, the foil not bucking as much as I was expecting! The mast is about 10% heavier than my old Starboard GT which you do notice when holding it but can't feel underwater.




I have measured these against my old Starboard set before I sold it. but forgot a few measurements.



Can we Please agree on a standard fuselage mount design!
F4 foils bring the flexibility of modular fuselage design with the mast connection secured with 3 screws, similar to Phantom (3), Starboard (3+2), Moses (3), Select (2+2), Patrick (2), Bug (5), Boss (3).... and unlike AFS with their solid (yet short) fused fuselage, and LokeFoil with the compromise design with fixed short fuselage stub and 6 mounting screws and lapped joints for the corresponding foil stubs.

While I admire the innovative designs across all the brands, can't we agree on a standard for mast to fuselage mounting similar to Tuttle boxes? This would allow designers to focus on the best foil to fuselage design but give the consumer choice about masts and easier brand migration. Unfortunately, Foil to Fuselage options have gone way too far past standardisation I believe.

And this is where F4 have gone the furthest... with 5 screws on the front wings, boasting a wide mounting plate for the front wings to help prevent roll and any sideways movement of the foil when under load. An upgrade on last years 4 screw design, but a little excessive when your trying to fit that last screw at the beach while the wind is calling.

Feel on the water


I have only had a few flights and am glad to report I have no buyers remorse. I definitely need more time on the water to get the most out of the new gear, but the few flights I had have definitely been memorable, including a pod of dolphins last week off Kurnell (bucket list experience ticked!).

There are a few differences in foil design to mention with F4. My AFS was pleasingly slick through the water, making the scythe like 1000R wing surprisingly easy to pump onto the plane... and fly. Something I missed when I switched to Starboard, the 900 noticeably 'draggy' when trying to push it up onto the wing.

Thankfully with their thin chords the F4s feel like they just want to fly! Slicing through the water with less noticeable drag, the board feels more eager to fly, but only after trimming the mast angle. The first few rides with the 945 wing were a little difficult to fly without stomping on the rear edge of my board as the mast set at +3?. When I used a shim and set it to 2? the next day I could feel my pumping action was much more effective. I've read a few recommendations about this angle over the year but never paid it much attention. Thankfully with all the mast box shims it will now be easy to adjust this angle.

The slalom wings have a fairly familiar design, flat section inboard and dihedral towards the tips. The Race wings have a mix of small dihedral in the mid-section and anhedral or horizontal tips... very different to my old AFS 1000R winglets! I have no insight as to why, all I can imagine is that more of the surface area and lift is directed vertically, rather than the lift vectors pointing apart.

Finally at the back, the rear wings are tiny! They are actually a bit wider than Starboard, similar to AFS in this respect, with shorter and thinner chords. As well as the shims to adjust the rear wing angles, F4 provide a range of fuselage lengths designed to bring the front wing further back to help with control as the wind and your board speed increases.

In terms of ride feel, I've only tried each fuselage once or twice and not all the rear wings or shortest fuselage yet! I am still waiting for a chance to try the shims out as they will likely help trim the flight when I find the right setup for my flying style.

945 Race


The main race wing is wide and very high aspect as I've mentioned, with an interesting profile perhaps like an Albatross rather than a seagull or scythe. The only realistic option for upwind coarse racing is the 115+ fuselage which is about 16mm further forward than the SB. This is the setup for max performance but does require attention to keep in control even with the mast base mounted forward.

The F4 Front wing sits forward of Starboard, both on "115+".

In very light winds I found flight easier to achieve with a rearward mounted mast and sail. I'm yet to experiment with the shims. Compared to my old SB900, I found this setup easier to pump from plodding 3kts to about 6kts, but the takeoff speed might need to be a bit higher with the thin chord, or maybe the tail needs a shim for lighter conditions. Or maybe I just need to practice more,. time will tell.

The 945 on 115+ is likely the best (and only) race option for 9.0 and 10.0 conditions. I used the larger 230 rear wing but will try the 210 out soon.

On the 115 fuselage which is almost identical to the original starboard 'black', the upwind performance is a little lacking, but stability greater and I felt much less likely to be overpowered by the front wing. This option might be better suited for light wind slalom and cruising, when upwind at 45? isn't essential.

Note to self: Don't turn up to a regatta with new kit and find this out mid-race!!


850 Race

On the 100 fuselage the 850 race wing had a minor "porpoise" like feel on my first and only ride out. Switching to the longer 115 [+] should defiantly help when I get a chance. I'm still learning to get the most out of it, in terms of speeds up and downwind so can't really brag on this point yet.

For gybing the 850 definitely holds enough speed and lift through the gybe (I made a few flying gybes first time out!).

I used the 210 rear which felt fine but can't comment on comparisons yet.
I suspect the 850 Race wing on 115+ fuselage will be a good combination for strong wind course racing, say with an 8.0 or maxed out 9.0. This wing with 115 or 100 fuselage will also give plenty of lift for ultra-light wind slalom.

620 Slalom
In really light winds I struggled to keep the slalom 620 in the air, during my first and only light wind session (10m sail and 8-10kts!) with -3? rake. More speed is definitely required for this wing, and more wind/pumping! To be fair, I would have preferred a 945 wing for this day, but it hadn't arrived in the country yet.

Next time I went out was after the Tiberias PWA in a strong and gusty offshore W/SW gusting 8-25kts. Longer discussion of that session here.. www.seabreeze.com.au/forums/Windsurfing/Foiling/Foil-vs-Fin-the-PWA-Experience?page=1

The 620 slalom wing has some good performance, but maybe 15 knots of wind speed is more ideal than 25kts! I'll update you when I've had more time on these slalom wings.

560 Slalom



I've only ridden the smallest wing once, and was pleasantly surprised how well it flies once up to speed. At slow board speeds, if I applied too much back foot pressure to early the board changes pitch but I felt the wing stalling under water. Once up the flight felt comfortable especially in the lullls when I could sheet in and cruise past planning boards and foiling windwings with ease. Race conditions will take a bit more tuning!

In the bigger gusts my 7.7 sail felt WAY too big! Sometimes I had the sail sheeted in just enough to ensure the wind was passing over the right side of the sail... cruising at 20knots with way more potential. It was an experience packed day. I've always been pushing for bigger and more stable sails in stronger winds, and now I need to think about changing down 1m or more when on the foil for slalom.
In some more manageable gusts I could sheet in about 50% of available power and sit into the harness and it felt good, but on my first session not so good that I couldn't quite match my own fin speed, managing just 25 knots on the foil vs 30 knots on my fin. I'll need to try the 90 fuselage and maybe even the 115, both of which mount the front wing further back. Alternatively pushing the mast base or foot straps forward could also help.

Flying gybes on the small wing proved elusive... I kept loosing too much speed by mid-corner and hit the deck by the foot change most times. I need to put in more work on the small wings. The feel is quite different to 850 & 950 wings of course.

Nico makes it look easy but going past 25 knots on a foil takes more time on the water than I've had! I can't imagine what 35 knots feels like!


The shorter 100 fuselage and slalom wings I've been riding at first also has a much more rear foot oriented ride compared to the course race set. I'm yet to try the 90 fuselage.

Below shows 115+, 115, 100 and 90 fuselages.

Bag
The packaging is very familiar.... the square travel bag is exactly the same as the Starboad model, just a more stylish black instead of grey. It gets heavy with both full sets in, but they all fit with plenty of padding between parts. The 3 longer fuselages go in the special slots and the shorter 90 just fits in the top outside zipper pouch.

With 4 fuselage, 4 front wings and 3 rear stabiliser sizes to choose from, I'll be set for any race day from 6 to 36 knots, slalom or course. The only thing missing from the lineup is a tiny 420 front wing for speed (which should be available soon!).

Shims
There are a wide range of rear wing shims and foil mast base blocks to choose from!





Quality
Initial inspection of the carbon and aluminium parts was very pleasing. The photos show a lovely finish to the carbon parts which felt even better in the hands. I have noticed a small difference in shape of one tail wing between the left and right tips that is unlikely to affect performance. One of my masts had a tiny bit of excess gel coat at the joint with the fuselage that I have removed.
The 5 screw mounting for the front wings feels very solid and the wings sit snuggly in the cutouts, with the fit improving on the 2nd session. Each screw seems to have a lot of turns to bight into. Overall I'm happy very with the build quality.

Delivery
During COVID supply of everything has been disrupted. F4 have two or three distribution centres, and a new manufacturing centre in China. Supply is available and takes about 2-4 weeks. Justin at Windsurfing Religion handled my supply.

Summary
The Race set needs to be ridden on the 115+ to challenge for upwind angles. The 945 will definitely be my go-to wing for most sessions with either a 10.0 or 9.0. I'll probably only swap to the 850 for higher winds with an 8.0 sail.

For slalom race days I can imagine using a 9m sail with the 850 race wing for ultimate light wind slalom performance, especially if the gybe marks are in a wind shadow. The 620 wing should work well next with either a 9, 8 foil sail or 7.7 slalom sail rigged, then swapping to the smaller 560 wing and keeping the 7.7 rigged before swapping down a sail size as the wind builds. Just a few screws and your ready. Until the 420 finds a slot in my quiver, if the gusts and lulls are consistent then I'll keep the 7.7 sail rigged and swap to medium board and slalom fin. But if the lulls are patchy maybe swap down a sail size or two and stay on the small foil.

Fun times ahead!

Thanks for the review Berowne
Thorough and well written as always

On the slalom wings consider trying a 6m sail when the wind exceeds 18kts

Cheers
TK

Select to expand quote

Maddlad said..
Geez, how much money have you spent on foils mate :P

We need someone to supply the used market with high quality recent gear.

Select to expand quote

tonyk said..
Thanks for the review Berowne
Thorough and well written as always

On the slalom wings consider trying a 6m sail when the wind exceeds 18kts

Cheers
TK

6.3 on smaller wings felt surprisingly controlled, for a short 2 run session at least. I think Nico G was onto something :)

Wow, that sizing I use 70% of my foiling!
600 foil, 79 mast, 210 stab.....

Select to expand quote

LeeD said..
Brain fade.... 79 fuze, 65 mast...I'm losing it at age 72.

Now just trying to be helpful, try taking a choline/inositol 250 mg/250 mg supplement first thing in the morning, you may be surprised how it can help your short term memory and brain function in general. NOW, Twinlabs, and Country Life are all good brands.

Select to expand quote

LeeD said..
Yeah...living on 512 a month, US dollars

It is cheap, Vitacost has the NOW brand choline/inositol 100 capsules for $6, three month supply.

Been on 1150, 79 fuze, 310 stab past 4 days.
Switching back to 600/210 this coming week, if tide holds.

Kinda lucky.
At 72, I take no supplements, have not seen a doc/dent in 30 years, don't take any pills.
Maybe because I can eat anything I like and avoid foods I don't like....veggies, fruit.

A 210 stab requires much more boatspeed, gets to the point of unstable with a 79 fuze, and seems to need not only 1-2 meter bigger sail, but benefits from much heavier slalom race sails for stability at speed.
For me, this translates to 6.5 meter multi cam sail in 15 knots....or bigger.
With 1120 and 310 stab, same 15 knots, a 4.5 is more than adequate, but slow.

Select to expand quote

berowne said..
Forgot to mention that F4 and my local importer offered to replace the very minor deformed rear wing a while ago. Great product and service.

I would get the replacement rear wing, it can have a significant impact in light wind and up wind angles.

After reading Berowne's F4 blog from yesterday I will add my Saturday on the same 2021 F4 race foil setup
Headed out around 11.30-12noon with wind 8kts gusting to 10, we dredged till outside the seaway in open water
We did a 95km return trip down the coast over about 4 hours
BOM readings at seaway during the journey were a steady at 8-10 kts with gusts 13-14
Board - JPHF 150, Mast base at the back of the track
Sail NP V8 flight 8.0m
2021 F4, wing 950cm2, stab 230cm2 with 0.75shim, fuse 115plus,
foil mast rake 2.6,
Power to burn with the F4 100cm wing span / 950cm2 area
Happy Sailing
Cheers TK

New unboxing video from the guys that put the F4 in the box.

Select to expand quote

tonyk said..
F4 FREERACE option

Suitable for anyone wanting to upgrade to a performance foil without breaking the bank

www.f4foils.com/products/windsurf/freerace-windsurf/f4-windsurf-freerace-foil/

It comes with a 850cm2 wing, 210cm2 stab, 97.5cm fuse and 97cm high modulus mast

I often use this same wing and stab with my 100cm fuselage and the performance and stability is amazing

Recent contact with F4 designer Chris Radkowski confirmed that the 97.5cm fuse has the same mast position geometry as the 100cm slalom

Cheers TK

Tony, what do they retail for in AUS

I've had two sessions on the tiny 337 Front wing now for 130km total distance.
Just a note... there are quite a few 330 tail wings in use in the foiling community, so this front wing is absolutely TINY!

Below got a bit long, so to summarise:
#F4Foils 337 cm2 area , 560mm span with 190 tail wing. Shim helps at the start but remove them progressivly as you gain confidence.
My Runs were on FMX 91cm with a 5.0 slalom and 7.0 foil slalom sail
Wing is small and loose, flys at 16 knots and has nice manners when ridden with confidence at 30kts. Rides like a speed board, push against the back foot, rake sail back and DRIVE down wind.
Gybes need more finese than I have.

So now the details...

First session was in a southerly storm front, Occasionally over-powered with a 5.0! Gusty 15-30But I managed 30kts peak and 29.6kts for 2s. Youtube meme's accepted:

There was some small swell, and I was probably riding with the mast 1cm too far forward causing me to tap down too often. Also it didn't help I wasn't confident enough to really push with both feet locked in! Scary!.

#F4Foils 337 cm2 area , 560mm span - 100cm fuselage, ~2.7 degree mast angle and 190cm2 tail wing later with 1mm shim
#S2sails 5.0 4 cam slalom sail VENOM - originally rigged with high clew hole - firm leech foil style
#FMX 91cm Hyperion foil board
The feel of the new wing was LOOSE! It is so small, it is really easy to ride, much like a wave board. It flies surprisingly early, minimum board speed to fly was about 15kts (I was expecting 20).... and mid-gybe I think it was still flying at 11kts once, just before I stalled. But it does need POWER to fly. Plenty of lulls I was left waiting for the wind.


But I'm not after a good time, I'm after a fast time, so I headed off in search of some flat water. With the wind gusting over 30kts there wasn't a lot to be had. Everywhere I looked had swell over 15cm and in the middle, almost a metre! There were a few breaches and unintended arials while I got used to the new wing, and the power at speed. The ride is very much rear foot oriented at 20kts and front foot oriented as you accelerate.



After a break I tried the slalom clew setting since the wind was quite heavy and also added a small shim to the rear wing. This made the board flight a bit more controlled, but also tended to be a little too rear foot oriented and I needed to move the mast back as I kept tapping the waves on a speed run with trim just a little too tricky to balance above 25kts this first time out. This is actually the scariest part of foiling over 25kts... tapping the wave tops is like a handbreak, so balancing flight so you glide above the wave peaks, but don't foil out of the troughs.


Only managed 29.6kts (2sec) on first outing with the wing. More to come, this thing is fast! Oh and LOUD! The whistle above 25kts is inspirational... helps to push as the volume increases! Hopefully the video captures it. I'll need to sand the trailing edge at 45 degrees I hear.

www.ka72.com/Track/t/483557


Next session was a summer N/E seabreeze, but no more steady, gusting from 10 to 25 knots at times.
#F4Foils 337 cm2 area , 560mm span - 100cm fuselage, ~2.2 degree mast angle and 190cm2 tail wing starting with 1mm shim then 0.7mm then none at the end as my confidence increased.
#LoftSails 7.0 4 cam SkyBlade 2022 - originally rigged with high clew hole - firm leech foil style then slalom high wind clew later.
#FMX 91cm Hyperion foil boardAfter about 20 more runs I got a bit more confident and started leaving the back foot in the straps, sitting in the harness and really driving through the legs. Takeoff needed the board to be planing and a few of the lulls left me wanting more, but in the gusts, I could just hold most of the power my 7.0 could deliver.

Towards the end of the day, as the sun was setting and my 2x GPS were warning me of low batteries, I started actually ENJOYING foiling at 29knots! My stance switched to speed style, pushing the power through my back leg, leveraging against the board, using my front foot to control foil roll angle and therefore pitch, rather than trying to push the nose down... and loading up the long harness lines, with some dramatic hip movement. The sail was raked back and I was outrunning all fin and foil sailors alike... except our PWA style NSW champion, he still had a few knots on me! Just not upwind! I'd gained so much confidencde I had even removed the rear shim entirely with the mast forward 5mm to compensate.

After 6 months I can report that I am very pleased with the F4 performance.
I've cracked 30kts (and want to work on this to get faster now! The new 420cm2 wing looks like it has potential!).
I've won a slalom foil race using 8m sails in about 12kts and the 560cm2 700 wing.
I've just won a Formula Foil race (slalom) with a 10m sail in about 8kts using the 945cm2 1000mm wing.
I got 3rd in the state slalom Fin and Foil and 4th in Formula Foil course racing.

So I'm very happy with the performance and overall ridability and responsiveness of the F4 foils. It did take a while to get used to the different feel and tuning requirements after riding SB foils for a year or so. For example I think the pumping technique needs a higher board speed before flight is practical, but then the drag feels lower too.

What impressed me about the 1000 wing yesterday is that this foil has the extra light wind lift for early flight and minimum gybe speed of a big wing, but can outpace a SB900 wing on the reaches (admitedly 10m sail vs 9m in 2nd and 9.5m with millenium wing in 3rd).

A few minor negatives though...
There is a rough edge where my foil integrates with the fuselage head. The carbon is inserted well into the 3 screw head but the filler has cracked a little.
One of the helicoils is wearing down somewhat premeturely. Maybe I should have used a longer screw to spread the load better...
The foils are not rock-proof and showing a few scratches from bottoming out.
The rake angle shims don't seem to be the right shape for my foil boxes (Patrik and FMX). I hope to get some custom shims soon. I don't think I have the right rake angle for the 1000 wing and board combination (1.5deg to 0.5deg last time out).


See all the action of my light wind formula foil slalom race on youtube...