Newbie questions.....Obviously weed fins are necessary for use in weedy areas, but what are the main differences in handling between using a swept back weed fin and a straight fin?
If there is not much difference, why not just use weed fins all the time in all situations?
Generally lower performance, centre of effort is moved too far back. You don't need that much rake unless you are going supersonic or maybe 50 knots. My opinion is that the difference is noticeable but no where near as bad as catching weed.
I run both and feel that the non weedies get upwind/ point higher especially in marginal winds.You don't have a choice if you sail in weed..
Loss of top end speed, nasty knife edge sticking out the back of the board just waiting to cut a foot or leg open if you're a clutz like me.
If you're just starting and you don't wanna spend the $$$ though, a weedy lets you sail where ever you want to sail.
Select to expand quotealbentley said..
Generally lower performance, centre of effort is moved too far back. You don't need that much rake unless you are going supersonic or maybe 50 knots. My opinion is that the difference is noticeable but no where near as bad as catching weed.
Agreed.
Select to expand quoteSubsonic said..
Loss of top end speed, nasty knife edge sticking out the back of the board just waiting to cut a foot or leg open if you're a clutz like me.
If you're just starting and you don't wanna spend the $$$ though, a weedy lets you sail where ever you want to sail.
it depends on what you call a weed fin, is 38deg a weed fin 
and it also depends if your going through weed or over, or there's a few floaters
you still cant go through weed beds with a wide board and a deep weed fin even if it 45+deg rake, even though they call them a weed fin
e,g yesterday there was a 30+knt southerly at sanctuary point, I was sailing with a n/p 5/0 n/prsr jp50 speed and a 18cm 47deg weed speed , I was too powered up and to much lift off the fin to sail into the heavy chop so had to keep pressure on the fin until i hit the weed bed at around 33knts then off the wind to get my max speed of 36+ , so in that case your sailing over the weed and not through it with no pressure on the fin
so the answer to your is yes you can use a weed fin as your regular fin but the wider the board the flatter the ride = bigger fin = more drag
It's not simple, there's weedies and weedies, some are crap and have given weedies a worse reputation than they deserve.
The main thing to look for in acquiring a weedy is how flexi it is. The stiffer the better, if you can put it across your knee and bend it more than a few mms don't even think about it.
A lot of weedies are just upright slalom fins reboxed at a greater angle.
Upright fins are OK with a bit of flex, some people prefer them that way, it can give a certain amount of vertical lift, but as the fin is raked back the vertical lift decreases rapidly, becoming almost negative and increasing drag significantly.
Also raking the fin back decreases the thickness to chord ratio, making it spin out sooner at high angles of attack.
I use 40deg weedies most of the time, (designed as weedies) they will collect weed at slow speed, but once planning they will shed moderate weed without even feeling it.
Most of the time if it's light weed you can get away with 30deg fins.
Yes the centre of effort is moved back unless you go for a delta type design, (these are suited for very shallow flat water, I'm not convinced about their use in deep choppy water).
The induced drag is higher due to an easier flow down the fin, but this only evident at high angles of attack, if you're going fast downwind it's not much of an issue.
I think there are riders that rely on the before mentioned vertical lift of pointers to help trim the board, and help lift it over the chop, when that doesn't exist the tail tends to sink a bit and you feel the effects of chop more. So there are definitely sailors who hate using weedies.
But I find any lift behind me, just pushes the nose down increasing the waterline and slowing me down, so I prefer using stiff raked back fins with no vertical lift.
Select to expand quotekeef said..
e,g yesterday there was a 30+knt southerly at sanctuary point, I was sailing with a n/p 5/0 n/prsr jp50 speed and a 18cm 47deg weed speed , I was too powered up and to much lift off the fin to sail into the heavy chop so had to keep pressure on the fin until i hit the weed bed at around 33knts then off the wind to get my max speed of 36+ , so in that case your sailing over the weed and not through it with no pressure on the fin
my idea of a weedy is using one to be able to GET planing!! Like for me having to use a big FSW (105L) in 15kn with a 6m. One ribbon of weed will stop u from planing.
Being slowed down by 3 knots would be a dream!!!!!
Then again I choose to do waves so more fool me..... 
Are weedies that start the leading edge in front of the box better as they keep the centre of effort closer to a normal fin?
Eg. http://www.chocofins.info/where-to-buy/shop/weedstar/
Select to expand quoteYuppy said..
i have got a weed fin if anyone wants it.
no charge. you pay for postage
Yuppy ... sent you a message!
Anyone use JP weed wave fins on their small freeride or FSW boards?http://jp-australia.com/2013/products/fins/weed/
How do they compare with the straighter outline freerace or slalom weed fins with regards to fin drive, handling and manouverability? (considering that all of the JP weed wave, freeride and slalom fins have pretty much the same leading edge rake angle)
Weed fins with narrow boards and narrow tails seem to be nearly as fast as pointers. But use a large weedy say 32cm and above on a wide board say 68cm wide and the difference with using a pointer is huge. Sailing a weed fin to me feels like the board wants to go sideways instead of forward.
central coast, nsw, we sail with only weedys, the jp fins dont get much credit but there good, big mike has been around 38kts on the jp 31, the jp 36 grips well with larger sails, i use the jp 26 wave weed alot, grips well up to 7m, and is fast, we are starting to also use the delta fins as well, there going well, we have older fins as well, finworks works well, those german fins go well, deschlessager???, the carbon fins are ok, in my opinion the smaller ones are ok, but the jps work well, i know people do go bigger than jp 36, but in my experience anything bigger just drags too much, initially weed fins feel like crap, but stick with them, if you have to, and they work well, i think in the early days i found them a little more prone to sliding, and turning hard into a gype used to be hard, but its all good now, you just get used to it, from a hobby point of view, a weedy will do everything, i know dudes at illawarra have done around mid forties on them, as decript said, if your light and lift isnt a problem, weedys can help keep it all down, we use weedys on everything from 130l slalom boards down to our 50l speed boards, sails 9m to 4.5m, if your gunna sail thick shallow weed banks, 30 degrees wont be enough rake, 30 degrees is ok for light surface weed, in my experience anything bigger than a jp36, is a waste of time, especially in thick shallow weed banks, but im 73kg, big guys, more back foot pressure, they seem to get good speeds out of the jp36, over 36kts with 8m plus sails on 130, 120l slalom boards, most sailors of all ability dont like weedys initially, but after a while most are happy to sail exclusively with just weedys regardless of if its needed or not,,, good luck all
I use a weedie on my boards if I the fin is too big. On my 125 Rocket I'd use the standard 44cm until it got to 15kts then change to the 38cm weedie and gain more control.
Select to expand quotered said...Yuppy said..
i have got a weed fin if anyone wants it.
no charge. you pay for postage
Yuppy ... sent you a message!
Sold to red .... For nothing. Good deal
Bump.
I'm a converted weedy after last weekend!
With onshores over the past few years I decided to buy a weedy about a year ago, but only used it on the weekend for the first time after a few days of SE'ers. I've been putting it off thinking that it would reduce performance & speed and only to be used if the weed was really bad (which it was)...I found the opposite! As soon as I plugged it in, my next run was blinding with good control, easier turns and after getting over the initial shock of slipping straight over weed - I didn't need to spend my energy dodging every bit of floating weed and didn't drop off the plane once. I did have to replace it with a wave fin after realising (the hard way) that it's not great when trying to turn on a wave.
I actually found the weedy much better than the freeride fins (multiple brands) I've been using over the years and contemplating offloading my freerides and replacing them with weed fins - will this be a bad decision? I still run slalom & wave fins at appropriate times, but can't work out when I would use a freeride fin now?
The fin was a 36cm Unifibre on a 116 Tabou 3S (if it makes any difference?)
weed fin for earlier planing ?
www.iwindsurf.com/forums/viewtopic.php?t=27256&highlight=weed+fins
Thanks Joe - some good informed/experienced points on that thread. I attribute the early planing to the size of the fin mainly - it states on the Unifibre web page that "Important: choose this fin 6-8 cm shorter than you???d normally use." The fact that I was using a 36cm with a 6.1m sail means that I was definitely over-finned, which was helpful in keeping upwind. Also the fact that I was starting from the shore with sloppy on-shore waves surrounded by weed - the freeride fin didn't stand much of a chance.
I guess the question is - with slalom fins in my quiver for speed, wave fins for waves & turns - is it worth keeping both freeride fins and weed fins for general stuff, or simply ditch the freeride fins? What is the purpose of having fins that aren't performance-based (freeride), when a good weedy will/should do the same job, but with the additional benefit of making sailing on weed enjoyable?
Select to expand quotejoe windsurf said..
weed fin for earlier planing ?
www.iwindsurf.com/forums/viewtopic.php?t=27256&highlight=weed+fins
I've got a 38cm Makani Hahalua weedie and have been really happy with it.
