Search for a Location
  Clear Recents
Metro
South West
Central West
North West
  Surf Cameras
  Safety Bay Camera
Metro
North
Mid North
Illawarra
South Coast
Metro
West Coast
East Coast
Brisbane
Far North
Central Coast
Sunshine Coast
Gold Coast
Hobart
West Coast
North Coast
East Coast
Recent
Western Australia
New South Wales
Victoria
South Australia
Queensland
Northern Territory
Tasmania
  My Favourites
  Reverse Arrows
General
Gps & Speed Sailing
Wave Sailing
Foiling
Gear Reviews
Lost & Found
Windsurfing WA
Windsurfing NSW
Windsurfing QLD
Windsurfing Victoria
Windsurfing SA
Windsurfing Tasmania
General
Gear Reviews
Foiling
Newbies / Tips & Tricks
Lost & Found
Western Australia
New South Wales
Queensland
Victoria
South Australia
Tasmania
General
Foiling
Board Talk & Reviews
Wing Foiling
All
Windsurfing
Kitesurfing
Surfing
Longboarding
Stand Up Paddle
Wing Foiling
Sailing
  Active Topics
  Subscribed Topics
  Rules & Guidelines
Login
Lost My Details!
Join! (Its Free)
  Search for a Location
  Clear Recents
Metro
South West
Central West
North West
Surf Cameras
Safety Bay Camera
Metro
North
Mid North
Illawarra
South Coast
Metro
West Coast
East Coast
Brisbane
Far North
Central Coast
Sunshine Coast
Gold Coast
Hobart
West Coast
North Coast
East Coast
Recent
Western Australia
New South Wales
Victoria
South Australia
Queensland
Northern Territory
Tasmania
  My Favourites
  Reverse Arrows
All
Windsurfing
Kitesurfing
Surfing
Longboarding
Stand Up Paddle
Wing Foiling
Sailing
Active Topics
Subscribed Topics
Forum Rules
Login
Lost My Details!
Join! (Its Free)

Forums > Windsurfing General

Weed fin design

Reply
Created by graygeezer Wednesday, 25 Mar 2025
graygeezer
15 posts
Wednesday , 25 Mar 2025 11:06PM
Thumbs Up

Newbie here. Weed fin question. I understand the normal weed fin design moves the center of pressure back compared to a normal fin. If so, why not shape the fin in way that attempts to keep the center of pressure in the same spot as a normal fin? See diagram, not to scale, just to get the idea across.

Jetlag
NSW, 189 posts
Wednesday , 26 Mar 2025 4:31AM
Thumbs Up

Select to expand quote
graygeezer said..
Newbie here. Weed fin question. I understand the normal weed fin design moves the center of pressure back compared to a normal fin. If so, why not shape the fin in way that attempts to keep the center of pressure in the same spot as a normal fin? See diagram, not to scale, just to get the idea across.



Many do :-
Tectonic Speed Demon
UFO Weed Forward
Tribal Delta Sym
Unifiber Lessacher Anti-Weed
Black Project Kestrel
etc.

BSN101
WA, 2336 posts
Wednesday , 26 Mar 2025 5:31AM
Thumbs Up

You have drawn 3 different fins there too. Pointer weedspeed & delta. Range of use - no weed, some weed and thick weed in shallow flat water.

ptsf1111
WA, 296 posts
Wednesday , 26 Mar 2025 7:17AM
Thumbs Up

It's called offset and is exactly what many weed fins already have as per above.


decrepit
WA, 12465 posts
Wednesday , 26 Mar 2025 8:04AM
Thumbs Up

The problem is mechanical, you can't shift a fin of any size forward enough, because it's attachment would be too weak.

Your example is very close to how a lot of us make our fins, that fin is short enough for the thickest part of the fin to still be in the box.

But I don't do it like that my boxes are set 10mm further forward in the board, because I always use shortish weedies.

elmo
WA, 8780 posts
Wednesday , 26 Mar 2025 9:12AM
Thumbs Up

If you have mild weed you can use a more upright fin with less rake, the denser the weed (or a shallow start) is, the more rake.

Sailing predominantly with weedies, it's just a case of shifting your mast base back further.

Subsonic
WA, 3235 posts
Wednesday , 26 Mar 2025 9:49AM
Thumbs Up

Tribal weed speeds are a pretty good compromise, but best suited for lighter weed spots due to less rake.

fangman
WA, 1806 posts
Wednesday , 26 Mar 2025 3:57PM
Thumbs Up

A fillet helps a little spreading the load, but even with 3D printed fins, I can put the box way aft with no structural failures...yet.

decrepit
WA, 12465 posts
Wednesday , 26 Mar 2025 4:53PM
Thumbs Up

Is that a carbon rod I see, running from the tip to the middle of the box?



Subscribe
Reply

Forums > Windsurfing General


"Weed fin design" started by graygeezer