Gestalt forum posts in last 60 days

Southern side of di.






Northern side

gandalf99 said..
Bit of a silly topic perhaps, but curious if I am missing anything:

Assuming the sail has correct downhaul tension, are there are any changes/consequences to be expected when the entire rig is, say, 4cm higher than it would be if it were pulley-to-pulley at the bottom?

For a simplistic example, if the downhaul number is 374, you can rig a 370 with 4cm extension and pull all the way down to the bottom pulley. Or if you had 8cm extension, you can downhaul until you are 4cm from the pulley. The sail has the same tension/shape in either case. Your body is now 4cm lower at any given point on the sail, which should be mostly irrelevant unless you got silly with the number.

Is there anything else that will happen doing this vs. rigging with the minimal base extension? There are a few different reasons for doing this, one of them is that on some very tiny sails the boom cutout is too low. Raising the whole rig allows me to have the correct boom height. I've done it countless times with one particular sail and its seems no different to me.

I can’t see much of an issue doing this. A lot of people set +2 on their extensions so they can go +1 if it’s cranking. Or if your sail has odd numbers on downhaul length and your extension is even numbers you can’t go block to block. Important part of your post is that you are applying the correct downhaul.

If you are using a much longer extension to allow the extra 4cm then this is not ideal as the extra extension length changes the mast bend curve. You will notice most sail sizes are designed to work on shorter extensions. This is done on purpose by the sail designers.

Can’t see how outhaul would be different as everything is going up 4cm.

Needing to add 4cm does seem odd though. Are you using sails designed with lower clews and boom cutouts like the severne redback?.

Paducah said..

Chris 249 said..
If we do some research about the physics of planing hulls, then we see that they’ve been well and truly explained since before David Savitsky did his work. We then know that the physics of planing hulls show that a short, wide area of contact with the water is more efficient in terms of lift for drag, because drag drops by the square as width increases. We can see pretty easily that even if the board was only planing on the tiny patches at the back of each “sponson”, then in just about any chop the waves will be hitting the “tunnel” which will increase wetted surface friction.

If we do some research we also find out when guys like Jim Drake created the shift from skinny Capricorn-style narrow boards to the wide style boards that have dominated windsurfer design for the past few decades, it was because they had done the research and knew that for planing, a wide aspect ratio planing surface is generally far more efficient. So if we do our research on the idea, we can see very good reasons to say that it probably won’t work any better than when it was tried about 45 years ago,

Lindsay Lord (1930s 1940s)
books.google.com/books/about/Naval_architecture_of_planing_hulls.html?id=f_wZAAAAIAAJ

His research suggested to a 2.5 to 1 length/width ratio similar to what we would eventually see in formula windsurfing boards

which led to Bob Simmons (1950s)
www.surfline.com/surf-news/bob-simmons/89860

Lords book is a great read. There is also lots online from bob simmons research. If you are into this stuff this is ground zero. The shapers handbook is another excellent resource. Especially if your aim is to design boards based on functional choices as opposed to doing things cause they look good.

Ok so i found the updates. There are videos on the wissant facebook page. Interestingly i had no idea there was even a wissant page. But there you go.
do i really need to watch a bunch of Facebook videos to get an update? That aside, the video is posted after the day has occurred. That’s right you are watching wrap ups not event info. Am i going to stare at a screen for 8 hours waiting to find out nothing happened. Where is the running description on whether things are on hold or when is the event postponed to. As an aside i don’t have this issue watching wsl events. Their communication is excellent.

facebook has limitations. For starters posts disappear from the front page and this gets worse the more fluff posts that get made. There are so many simple, cheap ways they can address these things. But they don’t. it’s been a complaint for years now.

Anyways i’m done. I’m tapping out of wissant. Time go windsurfing.

I dunno, feels like it’s by design. Been the case for multiple seasons now. I don’t think they are trying to cater for the spectators but more for the competitors based on the publicity.

it takes time to shoot competitor vids and edit then post. Takes less time and cost make a post on facebook and pin it to the top. So not sure it’s s cost thing.

I have. Got a board delivered via e-go. They doubled the cost after delivery and i couldn’t get a refund and struggled to actually talk to someone. Eventually ego claimed the box was bigger and heavier than the original quote figures.

i haven’t used them since. It felt like a shake down.

sprayblaze said..
Only by the looks of it the new boom head does not seem any stronger or more ergonomic than the old and proven one. I don't want even to imagine what might happen in the rare event of a plastic crack.. The integrated bumper is gone- no board protection whatsoever. 20% lighter hollow point bolts, less swing weight.. oh, come on.. I am keeping my lockjaw.

The older head doesn't lock as tight as other brands fwiw. simmer for example is firmer on the mast..

Severne not quite as firm. Looks like the new head design is firmer . Time will tell.

I can't speak to your experience unfortunately.

Can confirm posca pens with clear coat acrylic are commonly used on boards for graphics. I use them to hand draw logos on my boards.. with any type of additional coatings though the surface needs prepping and you need the correct finish coat in multiple layers. I’ll try a pen on my boom and see how it lasts. I only have black and the boom is carbon so it may be hard to see.

have repaired a few surfboard and applied a thin layer of coloured resin to hide yellow foam etc only to have it peel off.. 320-400 grit is needed to get a good bond.

Out of all the sails on the market, the one brand that relies most on having the correct outhaul to rig the sail correctly is……?

ezzy…

Not about niggles, it’s about correcting poor advice so people who aren’t as experienced don’t get lead up the garden path.

just yesterday i commented on a mates wave sail that it looked way over down hauled for the wind. he replied he needed that much for rotation. After the session i asked to look at and tweak his sail.. i was left with the thought that somethings not right… on further discussion he's using an off brand 430 mast in a sail that requires a 460 and went on to say the numbers were out because he has to under downhaul the sail even though it look over downhauled…he went on to say that he needed less outhaul or the sail was too flat. Said, i’ve got a 460 maybe i try that next time…

Fwiw my mate has had rigging issues since he got the sails but is constantly using off brand masts and extensions which is creating outhaul issues, rotation issues etc. so Yesh, the numbers and gear do matter.

Jasonwave said..
On top of my ailing eyesight, the length numbers on my boom are becoming unreadable from scratching. Is there a lasting way to highlight the typical lengths I use ?


Mast extension seems to be going the same way too.

Can you buy a new tail piece for your boom…

or just replace it.

the duotone zero point is not at the pulleys like other extensions that are block to block so if you are down hauling with the pulleys as reference then…..

Mr Milk said..
Yes, but a 5mm adjustment to outhaul is only 25% of a boom length adjustment. The boom usually stays set at the same set of holes.
Raising or lowering the boom affects the vertical leverage element of the aerofoil. Outhaul varies the belly.

Yep it effects leverage and mast foot pressure, but raising or lowering the boom also effects belly below the boom. Lowering the boom increases tension at the clew and removes shape from below the boom. Opposite for increasing boom height. ie. if you want more outhaul then lowering the boom height does a similar thing. that has been my experience…

if you need a more experienced view. Specific point is 9.37 in but you may find this whole video informative.

Lots of threads about sails not working with masts both now and historically so I did an ai deep dive to confirm brand differences.

If a brand is not listed I couldn't find the data.
What stands out is that every brand uses a different bend curve. Some brands it varies depending on mast length. Some brands also change from year to year meaning some pros get new masts from year to year. What stands out is whilst there are the rare crossovers it doesn't take much before a mast goes from being ideal to not so ideal.. Designers wouldn't design to 0.5% unless it made a difference to them. Not to say as punters we need to be within 0.5% but looking at the numbers below more than 1% and we may not like the results. Additionally the data below does not take into account variations in stiffness, taper and outside diameter which are also different from brand to brand and within each brands range.

and the real issue which is hiding in plain site. all the data below is taken by measuring the mast and not what happens when you load up the mast with the correct downhaul tension. Even though 2 masts may have the same bend curve percentages they will perform differently due to luff curve, carbon content, reflex, taper etc etc. yes it's a minefield.

Hoping more brands make their numbers available however I get it's IP.

Powerex 64/76
Unifiber cc 62.5/76
Unifiber fh 64/79
Unifiber fl 62/77
Duotone 61-63/75-77 depending on length.. the sls varies from year to year to suit sails.
Goya 340 - 65/78, 370&400 - 64.5/79, 430 - 64/78, 460&490 - 64/77
Neil Pryde 400 to 490 - 61/77 not confirmed.
North (pre 2017) 63/75-76 3di era varies.
S2 Maui 63-65/74-76
Ezzy 62/77
No limitz original 64-64.5/77-77.5, Sumo (stiffer imcs) 370 - 64/78.5, 400&430 - 64.5/77, 460 - 64.5/76.5
Sailworks - same as nolimitz sumo.

both point 7 and severne use different points to measure their bend curve..