Posts by Erik Loots

    Dominik, too big or small is relative to many (variables) like you mention. It is always the combination of variables which makes the behaviour. For example:

    • Ideal finsize for my 73cm board with 7.3: 35cm Sonntag GPS6 , 36cm Sonntag SL-Pro or 38cm Tribal slalom MK2. Between these 3 carbon fins designs there is 3cm difference. So there is not one best ideal lenght for a given board+sail. If I would include weedfins and G10 fins the ideal length difference is 10cm. Same with rake and thickness of profile (these are all totally different in this example);
    • In the past (long time ago) I did some fin testing. With exactly the same carbon fins (shape, rake, profile, etc.), only different carbon types and lay-up. The lay-up influences the power and behaviour, a stiffer fin had to be used shorter.
    • With less rake the fin delivers more power. Less rake and the fin can be used shorter. However too less/much rake and fin becomes unreliable (even dangerous),

    My best fin for 1 hour (ever in 2010) was a Sonntag SL-S 30cm (flexy fin), where I decreased the rake (1 or 2 degrees) to increase power a bit for crosswind speed, I was just below 80kg weight. Today I am a bit more than 10kg heavier and this SL-S fin works, but often bends too much (=less performance crosswind). I sold most my SL-S fins too lighter windsurfers. Today my best allround fin (highest speed crosswind) for 1 hour is probably the Sonntag SL-Pro, however my personal condition and surfspots are less ideal (I probably won't break my older personal record for this reason). My fastest 1hour last 5 years was sailed with a tribal Slalom MK2 34cm (under 63cm board), the tribal may be a bit slower crosswind (compared to Sonntag SL-Pro), however it is a fin with easy behaviour (less fatigue for me).

    Be warned, the Sonntag SL-Pro can be ordered in many different lay-ups (from speed orientated up to allround), my Sonntag Fins have the allround lay-up (biggest range and comfort) for my weight.

    We stopped selling a fin once it sailed bad for some years now. Over time we (me and my brother) learned most findesigns do have some advantages (in general), for example:

    • Sonntag SL-weed: a weedfin which is fast on all courses, my low+medium wind favorite. Thick weed is too much for this fin
    • Tribal weedspeed: very fast downwind and crosswind + in chop (due too more lenght) a nice feeling (a bit more shock absorbing). Thick weed is too much for this fin. Upwind is good, but not best.
    • Sonntag SL-pro: fastest crosswind and AVG speed (if I have a good day and can sail very powered up), can deliver high topspeed (mainly because you start with high crosswind speed). A good fin to overtake others. Works not with weed.
    • Sonntag GPS_6: fastest downwind if there is flat water or regular (not too big) chop. Works not with weed.
    • Tribal Slalom MKII: fin with shock absorber, in chop (due too more lenght) for me the best feeling. Fast design, especially downwind. Works not with weed.
    • Finish weed: 45degrees weed fin, if the weed is too dense (or water too shallow) for Sonntag SL-weed / tribal weedspeed with less than 45 degrees rake
    • Tribal powermax: allround (as long as no weed), not fastest however easy and safe feeling. Works in large windrange and is least sensitive for rider input/trim. A good fin to overtake others. Works not with weed.

    There is not one (easy) answer. It is difficult to find the optimal size if you use a freeride fin, because a good freeride fin has a lot of bottem end power and bends (looses power) once powered up. The freeride fin works simply in a large range without problems, that makes it hard to find the optimal size.

    It is much easier (and required) to find the optimal size if you use high performance fins, because these fins have peak performance over a smaller operating range (outside of the range it will feel not good at all):

    • A too small fin: Too much force for the fin (while boardspeed is low) means a drifting (high angle of attack) board. If angle of attack is to big the fin will not be optimal, upwind speed is limited when drifting. Extreme drifting (angle of attack) will make a spin-out;
    • A too big fin: Too much fin in the water means you will fly out of the water. It can be the board is railing out of control, or the complete board will lift out of the water. Or the board will be too loose and the fin ventilates (result spin-out), this can happen in lowwind too. Another symptom is that it is hard to keep your front foot in the footstrap. Or another symptom is when you can only windsurf a small distance (gear feels exhausting to use, sometimes you have too push hard on back-foot).

    If a freerider uses 1 fin to cover the operating range, than a freeracer needs at least 2 fins for the same range, race/slalom 3 fins, speed it is even worse.. The need to find a better/optimal fin is very much influenced by the type of gear. It is personal, I always liked to go fast on gear (fins, boards, sails, etc.) that could be used over a very large operating range. While to get the ultimate speed it will be more like formula 1 racing and have several pitstops to optimize, this was never my strong suit.

    Weed-Finnen habe ich nie verwendet. Auch nicht als der Wasserstand in den letzten Jahren auf ein absolutes Minimum gesunken war und ich mit den Carbonfinnen immer wieder Reparaturbedarf nach Grundberührungen hatte und die Regattafinnen dort gar nie fahren konnte, weil zu schade.

    Klar haben Weed-Finnen weniger Tiefgang und viel mehr Rake. Wie verhält es sich mit der Fläche und Profiltiefe?

    Profiles weed and normal fins are about the same. However because the weedfin cord-lenght is bigger, the weedfin is thicker. This applies to Tribal and Sonntag (I checked these fins profiles).

    Area is (much) bigger on weedfins, see for example Sonntag chart:

    A 36cm SL-weed is equal too 48cm SL-pro. I used last week this SL weed 36 cm for the first time and it is really good in lowwind (8.5 + 83cm from 12kts), good upwind and still capable to do over 30kts boardspeed.

    Weedfins are raked back.


    -Finpressure is more to the back, this means the sailpressure is (much more) in front of the fin. The sailpressure pushes the nose downwind, this limits upwind performance and angle.

    -In chop the tip of the fin delivers more lift, with weedfin this means in chop a weedfin upwind performance decreases more.

    -a weedfin has more surface, this means the fin has to be used smaller. How much depends on the finbrand (materials and shape)

    -because of the raked shape the weedfin needs a lot of material stiffness (strenght) too work. Using cheaper (soft) materials will have very strong effects on performance compared to normal fins. Thicker G10 (like tribal weedspeed) or good carbon weedfins make A BIG difference for everyone (especially to be noticed upwind). How the materials are use (quality and orientation of g10/carbon) has huge impact on performance.

    -due to shorter lenght more sensitive to spinouts, especially when fin is made from softer or lesser quality materials .

    -more difficult to remove the fin from the box. Especially weedfins that start (and/or end) in front or behind of the tuttlebox can damage the bottom of the board.

    -you have to be a bit more carefull because the fin is behind your board. When swimming/walking around the board it is mote likely you hit the fin with your leg.


    -weed doesn't stick on the fin

    -shorter means you can sail in more shallow spots

    -due to raked tip it means if you hit the ground the fin will slide a bit more over the ground. Less chance the impact of ground will result in immediate stop/catapult

    -on downwind course in upper end of windrange of your board the control (and boardspeed) will be better in regular (small) chop. The board will go easier downwind.

    -if there is floating trash in the water (wood/bag) a weedfin will often push the trash down and you will not crash. I often use a weedfin in new (unknown) spots for this reason

    -windrange is bigger with a weedfin (because fin is shorter it is easier to control in higher wind). You need less fin changes

    -good weedfins loose less value, they are needed more and more due to water quality in Europe. I had a very damaged Hurricane weed2 of a few years old and bidding was up to 70% of new price to my surprise in a few days.

    Some windsurfers keep using weedfins (even without of weed) due to the advantages. These windsurfers use good weedfins. Better spend a bit more in one good weedfin, because the difference between good versus cheap weedfin is much bigger compared to normal fins. I like the tribal weedspeed (best g10 fin so far), Sonntag Sl-weed is very good and hurricane weed3. These 3 fins work good allround. I have also tried many other weedfins that had disadvantages which made them less allround (too soft material, too much rake, weedfin damaged board when removed from finbox, very expensive, too short, easily damaged, poor finish). On very shallow spots or very thick weed you need a (less performance) delta fin (50 degrees rake), in the Netherland I did never need such a extreme (less performance) design yet.

    Without buying another more powerfull weedfin the best thing is to move mastfoot forward (which will decrease the pressure on your fin, result should be less spin outs). Another thing could be a bit more downhaul on the 7.7. At last the technique, if you have to pull a lot on your backhand than your rider input is important for spinouts, for a lot of windsurfers it is easier when harnasslines are moved a little bit to the back of the boom (this makes it less sensitive for rider feedback.

    However the best experience would be a more powerfull weedfin for your 7.7. I dont know the depth and type of weed. For extreme weed and low wind I have a Black project Kestrell 26cm, the kestrell is more powerfull compared to your fin. I see your JP has powerbox, and my Kestrell is tuttlebox, otherwise I could send this fin by mail. I am thinking of selling my Kestrell for over 1 year now, because weed is never that extreme at my homespots (after 1 sessions to try I never used this fin again). If the depth and weed allows: A Sonntag Sl-weed or hurricane weed 3 36cm should be very good (much better than your current fin or black project kestrel).

    My best early gilde sail ever was the Loft raceboardblade 8.5 LW. I never wanted to buy a mast longer than 490 cm, this 2020 raceboardblade lw was rigged on 490. I bought both 8.5 loftsails switchblade and raceboardblade LW. The raceboardblade feels (and is) lighter compared to even my smallest Loft Switchblade 5.8. It is totally different, raceboardblade LW is definitly better in lowwind and verry light. However from 14-16kts my switchblade has a much more stable feeling. On the beach or in very lowwind the switchblade 8.5 feels at least twice as heavy as the raceboardblade. I used the sails on a raceboard and in big slalom mode, with faster boardspeed (above 40km/h), the switchblade feels much better for me. Lower boardspeed (sub 35km/h) the raceboardblade lw felt much better for me.

    I did sell the raceboardblade eventually, because I always changed for another sail once the wind was above 14-16kts. Also my homespot is not raceboard friendly (loads of weed in water). The raceboardblade is more difficult too rig. I didnt like too change sails often, that is why I sold the raceboardblade. Today if the wind drops (sub 10-12kts) I just wait, enjoy nature while sitting on my big tribal radix board. Which is fine because there are enough days for me with switchblade 8.5 or smaller to enjoy windsurfing.

    I wouldnt recommend a raceboardblade on a freeride/freerace board. However I can confirm the sail construction and weight does make a huge difference in lowwind if you want to glide for fun without an big effort.

    I use my switchblade up to 8.5 with a RDM mast and I am 90 kg. This makes the sail a bit less direct or less "Scheunentor". I used a SDM in the beginning in the 8.5 Switchblade HD, this made the sail very direct. I think for riders up to 80kg the RDM is often better "allround" in the Switchblade. I cannot comment on Sailloft, I don't have experience with this sail, the sails look good. How the Sailloft sails compare too Switchblade/V8 is not possible from photo's or specs. I can confirm the V8 with SDM is a bit less direct than Switchblade with SDM. And the V8 feels lighter. A switchblade on RDM feels about as direct or a little bit less direct than V8 on SDM. The Switchblade HD version also feels a tiny bit less direct too me compared to the normal Switchblade. My switchblades are all normal version except the 8.5 which is a HD version. Using the lower clew eyelet my Switchblades will get much less direct, I only use this clew eyelet in survival mode (when the sail is too big). The new 2024 Switchblade have a different eyelet position, I have no experience with this setup.

    For me Switchblade+RDM is chosen for safety (my homespot is not that easy and safe with cargo boats and hip height chop/waves). I don't believe the Loft Switchblade is the holy grail, however its a very good compromise when looking to something durable, direct and with many trim options which work good.

    I wouldnt know because I have not used the Moto and Turbo

    Difference is in my opinion/experience:

    freeride (often 2cam) early glide:

    -sail has more closed top above boom

    -sail has less tension and feels/reacts softer

    -due too less tension the sail opens up (looses performance) earlier to keep control

    -due too more closed top in lowwind the sail has more power (in a small windrange). For very heavy windsurfers this often doesnt work (because the sail is softer it deforms too much when windsurfer is very heavy/strong). For example my strong brother had a 2 cam Neilpryde H2 8.2 which was way too soft for him. He has now newer Neilpryde v8, these are stiff enough for him.

    freerace (often 3 cam)

    -sail has more open top above boom

    -sail has more tension and feels/reacts stiffer or more direct

    -due too more tension the sail opens up (looses performance) later. To keep control the sail has a bit more open top design

    -due too more open top in lowwind the sail has less power. When pumping or once planning there is no difference anymore. For very heavy windsurfers this often work better (because the sail is stiffer it holds better shape when windsurfer is very heavy/strong

    There is no holy grail, for example the Severne Moto is a very good sail. However it cannot be better in all criteria compared to previous overdrive or turbo.

    Also the amount of cams is not really the most important for early gliding. I believe the sail shape and tension is most important.

    Naish has a powerbox. There are not many second hand powerbox performance fins for sale in th Netherlands. Select fins, Hurricane fins, Tribal fins, Sonntag fins (and probably other good brands) do offer powerbox performance fins for 10+ years. However 2nd hand they are rare with powerbox head.

    The patrik board has a tuttlebox, which means a lot of secondhand performance fins available.

    The older Naish is 264cm long. The differences are not very big if I look to the numbers. An older board can be (internal) weakened when its used a lot and used intensive. Naish has had quite good constructions in the past (dont know about this board though).

    If the cost of the board is no issue I would buy the Patrik in best construction option. This board will last The Gecko is very wide, in shallow water (longer fin is difficult) or with weedfin this is an disadvantage. If you want the best performance for lowest cost than I would choose the naish and use the difference in cost for a good extra fin. Because I believe the naish with a good fin beats the others with standard fin. The Naish is probably the best board to (learn too) gybe fast. However you need to estimate (when buying) if the used Naish board is not near end of life.

    In my experience: if a (for example) 37cm is ideal, than a 38-39cm would improve in low wind option and 35-36cm for high wind. Or my 130ltr board it's the same (42cm) +-2cm.

    However some fin models are simply not ideal by design too use in lowwind (or highwind). The +-2cm rule works with allround Fins for me. For example, GPS speed Fins are often not ideal for lowwind, even in extreme long sizes. A lot of finbrands describe if the fin is allround or if a fin is specific good in low wind or high wind. I like allround because its easier to predict performance and trim (instead changing different fin model). I consider the Sonntag Sl-pro, Tribal powermax, Sonntag sl-weed, Tribal weedspeed as allround Fins. I also have tribal slalom mk2 fins, this design is a bit less allround, it's very good downwind and in chop and very fast and comfortable in flat up to chaos chop. I keep the mk2 slalom because of the benefits. But for lightwind, high crosswind speed (or no big chop) I rather use allround Fins.

    Falls die Nose zu stark steigt, was heist das für den Trimm? Mehr oder weniger LooseLeech?

    Less downhaul=lower nose

    More downhaul=higher nose

    I trim use downhaul mainly for getting not too much/less backhand pressure. If the sail reacts uncontrollable in gusts (too much power required from my backhand) I increase downhaul. In extreme gusty wind I use a bit more downhaul compared to steady wind. For me today, the mastfoot and boom position are the main tools to trim the height of the nose of the board. The fin is also a tool for the nose trim of the board, only it is expensive and it takes more time to trim with a fin (you need to change for a different fin).

    In the past (for speedsurfing) downhaul was my main tool to trim the height of the nose of the board. This changed for me, probably because I use different gear and sail at different spots.

    A few things you should know:

    -Freeride boards will work (much) better than freerace/slalom with your neilpryde v6 sails. Your V6 power doesn't fit modern high performance boards.

    -longer (more lenght of board) will work better and easier than short boards with your sail. New style (short boards, wide tails) need to have more power (longer boom, more area and pressurepoint in back of sail) to be balanced.

    Looking to recent boards a JP Super ride 139 comes in mind (244cm long, 76cm wide and 139 liter) as a board which (I believe) will make your re entry fun and as smooth as possible with a modern board and your current older sails. If possible, rent/try this JP board some where. Or look on 2nd hand market for a freeride board with 240-255cm lenght, older starboard carve is also a nice option.

    I use (2020-2024) my sails with RDM. My 8.5 was the last sail on SDM, when I changed to RDM with this big sail it wasn't faster. My homespot has some cargo boat traffic, when breaking the mast in the channel with cargo boats it can become dangerous quite quickly. I could choose to windsurf in the area downwind of the channel with cargo boats (but missing the best parts of the homespot). However I chose using gear with very low breakage chance ==> AL360 carbon boom from Totti + RDM masts for all sails.

    The biggest difference is the moment of inertia which is lower with the RDM. Every mast (and sail) bends out of shape when a good gust or chop hits the gear, this deformation means the sail looses power/drive/efficiency. The mast will swing back after the deformation, the higher (SDM) moment of inertia will help to get it back faster. For example:

    • If it would swing back to the normal position with a SDM in 3 second (and 3 swings);
    • my feeling is with a RDM has a worse moment of inertia, it is 4~6 seconds (or 4~6 swings). Soo you loose over a bit longer time a bit performance

    Sometimes it is nice to have a RDM (because it is to messy and the SDM feels a bit to much to handle), sometimes it is nice to have the SDM (because the sail with RDM bounces to often out of shape and lacks performance).

    I believe when windsurfing in good conditions (steady wind, nice water) there is little to none difference between RDM and SDM if bendcurve and weight are equal. Only in challenging conditions it feels different. RDM is not consistent better of worse, it depends on the day and spot. Changing SDM to RDM has the same effect as choosing lower % carbon masts (which also lowers moment of inertia).

    So here is my tip ==> if changing to RDM masts, make sure your carbon % is equal or higher than your SDM. If sailing in flatwater and consistent wind, the carbon % is less important.

    My brother uses a Sonntag Fins Sl-X 58cm with great succes under his lightwind board. Before the Sonntag he used large Select and Drake Fins. The Drake was actually fast highwind (30kts), but did show hairline cracks at the base (it will break at one point). Select was good low wind, but also showed signs of faitigue after many years of use.

    I would choose the board(s) based on the sails and Fins which you use with them. Also considering the waterstate and conditions you planning to surf is helpfull. For example I know a lot of windsurfers that like a monoconcave bottomshape for lightwind up to mediumwind in flat- mild choppy conditions, Starboard and PD offer(ed) a monoconcave board.

    Chosing boards from different brands can be interesting, if you know what you want. Testdays are great to decide. Or consult local windsurfers (sponsored) with gear you would like.

    However for most I believe 'logical' combinations would be the safest bet for fun and performance (fanatic-duotone, Starboard-severne, point7-av, etc. ). Other combinations might work great or might work (far) below average performance, you will find out. For example, Who knows if a iSonic works great with the current Ga-sails?

    Another strategy is buying boards without a related sailbrand (futurefly, i99, etc.). Often these designs are a bit more neutral because teamriders use different boards. Same with sails without a related boardbrand (loft sails, s2 maui, er.), these are often more neatral designer.

    For example, I was starboard fan for a long time, however the latest iSonics (I believe Iachino his sailing style influence) are not what I like. The fat ass of these iSonics combined with thin nose and short lenght is special to ride, but not better or fun for me personally. I did like the iSonics during Albeau/Dunkerbeck days a lot. Luckily I bought one and starboard sell good. Then I looked for boards which looked more like the older iSonics and ended up with Tribal boards now.