My attempt to make my 14' Jav more stable.

[DavidJohn]

http://ncpaddlesurfer.blogspot.com/2009/11/real-race-fin.html

Get a custom made fin direct from these guys DJ. They will make any size, any base. Price is fair. Shipped postal from Maui. You are not limited by what is shown on his web site. He'll make anything.

http://www.mauiultrafins.com/MUF7_english/SUP___Surf_Fins.html

Thanks for the links.. Nice fine.. I just might end up oing that.

DJ

[SUPpaddler]

Here's a 12" hatchet that puts a lot of area deep down there.

http://www.ebay.com/itm/DORSAL-SURFBOARD-FINS-LONGBOARD-HATCHET-12-INCH-BLUE-SUP-SURF-FIN-SKEG-/250993272338?pt=LH_DefaultDomain_0&hash=item3a705d6612

[DavidJohn]

Thanks.. That looks good.

Even that Naish dagger fin I'm using has pretty small tip area compared to that and that's where you need it.. It also looks like you can drag it in shallow water without catching.

DJ

[balance_fit]

Here's a 12" hatchet that puts a lot of area deep down there.

http://www.ebay.com/itm/DORSAL-SURFBOARD-FINS-LONGBOARD-HATCHET-12-INCH-BLUE-SUP-SURF-FIN-SKEG-/250993272338?pt=LH_DefaultDomain_0&hash=item3a705d6612

Not meaning to burst any bubbles, some things about this fin worry me.
Even though the general outline looks fine, it's made out of polycarbonate. Which means it's going to be very flexible and whatever theorical benefit in stability could be gained by it's 12 inches of depth and area at the tip, will be lost by it's flexibility.
Besides, i doubt that a polycarbonate fin can be shaped with an appropiate foil (NACA or similar) and be thin enough at it's thickest point to avoid causing tons of drag to forward motion.
From the product description, this confirms my suspicions: A rigid base combined with a tapered flexible tip results in a progressive flex pattern, for quick rail transitions and forgiving performance even in the sketchiest situations.
Just my two cents...

[DavidJohn]

I'm thinking some flex in a big fin might be good and will take some load off the box and also helps keep water flow on the fin.. also at our slow speeds we need thick foils.. Much thicker than the thickness of the fin box slot.. It's easier to mold a plastic fin with the correct foil than it would be to make one out of layed up glass sheets.. Also thick foils don't nessesarry mean slow.. One of my best windsurfing fins was a plastic molded fin that was long and had a fair bit of flex.

Here's another interesting fin from the 80's.. The Strata fin.. I'd like to see something like this only a little bigger.. It didn't work very well windsurfing (what it was made for) but I think the design would work well for sup.

DJ

[1paddle2paddle]

I purchased that Dorsal fin (though it might be the 10" version) for the old Naish Glide, but then sold the board without extensively testing it with that fin.

I will try the fin in the ACE to see how it affects performance.

[DavidJohn]

My fin mod #2.

DJ

[balance_fit]

I purchased that Dorsal fin (though it might be the 10" version) for the old Naish Glide, but then sold the board without extensively testing it with that fin.

I will try the fin in the ACE to see how it affects performance.

Please keep us posted on the results of your test !

[balance_fit]

DJ

Now the modification of the stock fin looks pretty sleek, please let us know how it works in the water. I got a similar fin, a G10 from my old windsurfing days, that's getting the eye....

[1paddle2paddle]

DJ, nice job on that fin.  The extension now looks pretty professional.

On to the thread hijack...I wasn't really excited about how the Allison fin worked with the ACE yesterday.  I paddled in the channel at Ala Moana Beachpark, basically a flatwater course a little over a half mile one way, then same back.  The wind was hitting from 10 to 11 o'clock paddling "up"wind, then 4 to 5 o'clock "down"wind, with very little fetch, varying from 10 to about 20 knots in gusts.  So basically you have wind forces but not any swell.  These seem to be difficult conditions for the ACE, as I would have to make large adjustments to my stroke to keep the board from getting pushed off course by the wind.  Whereas the ACE is a beautiful thing to behold going downwind, it seems to suffer in sidewind conditions.

The big Allison fin seemed to make the board a bit more stable, but it also made it less likely to respond to my attempts to keep it going straight on the course.

Perhaps it was just a bad day.  I'm going to do more testing.

[balance_fit]

I paddled in the channel at Ala Moana Beachpark, basically a flatwater course a little over a half mile one way, then same back.  The wind was hitting from 10 to 11 o'clock paddling "up"wind, then 4 to 5 o'clock "down"wind, with very little fetch, varying from 10 to about 20 knots in gusts.  So basically you have wind forces but not any swell.  These seem to be difficult conditions for the ACE, as I would have to make large adjustments to my stroke to keep the board from getting pushed off course by the wind.  Whereas the ACE is a beautiful thing to behold going downwind, it seems to suffer in sidewind conditions.

The big Allison fin seemed to make the board a bit more stable, but it also made it less likely to respond to my attempts to keep it going straight on the course.

Perhaps it was just a bad day.  I'm going to do more testing.

hmmm....i paddle very much in similar conditions, flat water with lots of side winds, maybe my strategy can help:
I'm standing on the ACE in between the drain holes for general conditions and if faced with side winds i'll slide the windward foot a bit ahead and the leeward foot a bit aft of this position. My center is still aligned in between the drainholes but the rear foot (leeward) is applying pressure to that side rail while the front (windward) foot is light or even close to the inner side of the footwell. The board is riding on it's leeward rail and steering upwind.
The problem with the fin you're using is that it's an excellent tracking fin, you'll be able to paddle for days on one side without change overs. But, when the need to steer into the wind arises, this fin design, once the bow is blown over downwind, it's a pain, it doesn't work.
The Curtis EJ fin is very similar and behaves like that. If i don't sink the leeward rail, i'm gonna get blown downwind.
When windy, i use a deeper design, with a similar area overall, and long base to keep the tracking, but using it's depth to help me steer into the wind. Kind of a hybrid fin, like the Gladiator Hybrid or the Curtis 777 (in my picture above).
Test some more, keep us posted !

[1paddle2paddle]

Wow my experience nearly exactly.  The only thing that helped keep the board going in the correct direction was to roll the board onto its downwind rail, which allowed me to prevent it from simply heading straight downwind.

More testing needed.

[DavidJohn]

I tested my new fin today.. and plucked out a few of those nasty bad starfish.

The fin worked great.

DJ

[covesurfer]

I ended up purchasing the Jav 14 that I had demo'd a couple weeks back and am loving it. I'm using a O'Fish'l fin that is pretty good sized but is also raked. I've gotten addicted to paddling the Jav vs. my other boards because it is just so much more efficient and fun to paddle.

I'm gradually pushing up the conditions I'll try it in - stuff that is mild on my Glide 14 can be a real challenge on the Jav. I walked off 3X on last night's paddle in one foot disorganized chop but I wasn't being as focused on staying on as I could have been. I was actually trying to see how sloppy I could get before the board and waves would school me.

I'm getting used to the tipsiness and see the attraction of a more stable fin but I'd be concerned about how the board would turn and go downwind. In other words, it seems like the tradeoff of greater stability via a larger fin would be that the board would lose its 'looseness' that is nice to have when catching bumps and changing directions. Seems everything is always a tradeoff. For fast flat water and mild chop, that long fin you designed - which looks awesome by the way - looks perfect. Curious how it will be in rougher downwind conditions.

[1paddle2paddle]

DJ, how tall is that fin now?