SUP specific fins

[Larry Allison]

Larry, Is that a hole on the surface of that blue fin?  How does the flow over the fin not get messed up by that?

Water does not notice the Hole on the Blue Bat Race Keel. Water only Notices the hole on this Jeremy Fin when in turn mode which is a much bigger hole my friend.
Mahalo,Larry

I am flabergasted by that, not what I would expect, but very interesting. So could I drill holes through my fins with no effect, other than reducing weight?

I find the weight comments always interesting and funny at best. When you step back and think about it, using a 10' board 4" thick and 30" wide do you think a couple of ozs is going to make a difference in the water.

A guy once told me that the weight of a positive fin displaces the weight of the rider. I looked at the guy and said are you kidding me. The rider is forward of center and your fin is at the tail of a board 6' to more behind you with the tail riding up depending on rocker. How does a fin weighing around 1 pound which is one of my fiberglass fins verses the positive weight of 3/4 of a pound effect you. Fiberglass fins have positive feel and a positive floating fin has negative feel which is hard to control when you have surface movement. In a RACE world, when water swell moves up behind you the board will roll tail first then middle to nose. With a  positive floating fin at the point of swell hitting you will drive the nose into the chop causing you to get thrown off the opposite side. If you had this happen then look back and see what you have on your board. Either under finned with a small fin or a molded floater fin.

What companies really don't want you to know that the costs of a lightweight fin, is really a overpriced molded fin with all the cool stuff inside doing nothing but creating a fashion look with poor performance in a standup world but good bottom line for the person selling them. Even hand made fiberglass fins from overseas isn't that cheap for big companies to push on you, so they sell you the easiest to make with greatest profit needing no skill and quality control along with telling you to get better at your paddling. This is funny coming from most companies that a year ago were selling you one color surfboard fins until their stock ran out.

So putting holes in certain areas of the fin will not effect the performance especailly in the bottom 3rd section which is over half the time out of the water on some boards due to rocker. Not to forget the more holes for weight, you will loose lateral resistance at load times which then creates fish tail effect and lost of forward projection when needed to fight the conditions in use at that given time.

Hope that helps answer some of your thoughts my friend and be aware of buying to much KOOLAID. And for you boat guys just curious do you know of any keels on boats that have positive weight? I believe they even have lead added for weight!


Mahalo,Larry

[Larry Allison]

^
Yes. For shorter boards, standard size fins seem to work better.  Looser is better, IMO.

What I meant was surfboard fins seem to be fine....rather than SUP specific...unless I have read that wrong. I've got 10 inch fins on my longboard and a 10 inch fin on my 12 ft SUP.....not a SUP specific fin.

Yes fine to the point that Mother Nature or your limits exceed the use of a surfboard type fin. If your are having fun then enjoy the ride (-:

[J-Bird]

Larry, Great info...I agree with you on the weight issue of fins not being a major factor...and I am not going to go and drill holes in my fin to reduce weight, just curious to how the fluid dynamics might work over the holes.  It seems like you are pushing the envelope on fin design, really cool stuff.

[J.Riggs]

We had a lot of paddlers come to Maui for some of the recent races and I was able to get a lot of them to demo the Aercor fin. The feedback was fantastic. The first thing people noticed was how much easier it was to paddle out of Maliko into the side wind. The hole in the fin allows the current and swells to pass through and you can keep the board going where you want it to go. The next big advantage is the ability to put your board in the correct position to stay on a glide or make a connection with just one quick directional stroke. The fin also made a difference inside the harbor where we have strong side wind but not the big swells. Usually the nose of the board gets forced to the right by the wind hitting the left side of the nose and the board pivoting on the fin. Having a hole in the center of the fin helps to correct that problem. Many of the paddlers using this fin did very well in the Naish race and the Molokai to Oahu race. If anyone wants to demo a fin here on Maui send me a message and I'll meet you down at the beach.