I finally got around to riding the Feather fins you sent me. The waves were only waist to chest high and nothing to get excited about speed wise. But, your fins were very quick and responsive. With the super short root cord length and all that rake I placed your side fins forward in my boxes. I normally ride my fin templates all the way back. But, my normal side fins usually have abit more fin infront of the root than your fins do. They seem to have a smaller plane form and tied with the short root cord length they were very low drag when paddling and almost felt squirrelly side to side when I would test them in a paddle. They were low drag while taking off and I got good projection out of my first bottom turn. Since it was small with a short shoulder I immediately snapped into a round house and I think I got behind it a little because the board wanted to finish it off as I was catching backup and there just wasn’t enough wave to get back on top.
My second third and fourth waves were a blast. Little lined up point waves that I just pumped down the line wacking the lip on every third turn and cutting back twice. This is usually my make or brake move on how I feel about a fin. When you are down speed coming out of a cutback in the white water. If you can pump out of that hole and everything else clicks then I’m happy. I was pretty happy. My last wave started out with a real slow shoulder from the outside and then just lined up into the cove between Lowers and Churches. At that point the wave was maybe shin high. I pumped down the line for 70 yards just hooking little top and bottom turns together in about a foot of water. Started getting nervous about how long and thin they are in the shallows and finally kicked out when there were more boils than clean water.
I’ll be pretty interested in seeing how they work with a bit more umpf behind them. But, for small waves they lit up my GP thruster to the point that it road more like a fish.
Does anyone know anything about J. Johnstone? I ran into Matt Biolas on the way out. They both had LP finished boards in their hands. I asked Matt what’s up with the Surf Techs and told me that these were not Surf Techs. They are a new no core construction method and are using “America’s Cup” building techniques to build these boards. Matt introduced us. But, I didn’t want to hold them up. So, I just thought I’d ask here if anyone has checked out these boards.
Hey Tom,
Glad to here that you’re back in the water again. I know that back injury was really a drag for you.
With less fin drag new vistas open up in the performance picture of three fin surfing. You made a good call on fin placement for the conditions you were. Someone with less knowledge of fin dynamics might have done things differently and had much less of a session than you did. When it gets bigger slide everything back in the fin box (an option that is delightfully available with Red-X) and see how things go. I think you find that the fins are speed sensitive enough that you’ll still be able to do the same roundhouse cutbacks, hold as high a line as you’d need to and even do a little stalling in the critical part of the wave and enjoy the acceleration out of the pocket that only a relatively low drag fin system allows.
Can you clarify your reference to a (( GP thruster ))?
Does that mean General Purpose?
Thanks for posting, the results of you session. I’ve been getting some real interesting feedback from other surfers. These sorts of reports make very rich fuel for the R&D machine.
Good Surfin’, Rich
Rich exactly right it’s my base line or “General Purpose” thruster. It’s 6’6" 19-5/8" X 2-3/4" with a 14-3/4" tail single to double concave bottom. Basically, I give my brother a 6’6"P ultralight blank and he skins the deck and takes rocker out of the belly with bottom contour. It’s been real repeatable for my last four baseline boards. I’ve got several other specialty boards. But, I ride 90% of the time on this board and just switch fins.
Hey Tom,
For the record ~ will you measure the depth of the fins. As I recall the rails are around 4.75" and the center is around 5.0" but I’m not sure.
It would help me to know how big they are because fin sizing is always real important performance issue.
I’m looking forward to a dot matrix sheet to measure fin surface area with that an engineer/surfer is sending me. It should prove very useful in understanding better how fin performance works.
When I’m first starting someone out with a Mental set-up I like to make the center 10-15% larger than the rail fins. It seems to stabilize the system better. On bigger boards with more nose I like to put some more holding power deeper into the water so I put a “Spinner” in the middle. I haven’t done it yet on a GP thruster but I think it’d prove very interesting.
Thanx for the board details.
Good Surfin’, Rich
The sides are 5" deep and the center is 5.2". But, the tip and base cords are very short. I’d guess their area is about 20% less than your typical 4-5/8" X 4-5/8" fin.
Hey Tom,
I remember when I did the project I wanted to give them a little extra surface area even though a 5.0" fin tends to look a little deep because of what everyone is used to looking at. I think the depth may have something to do with drive they provide (deeper = more leverage) I’m pretty sure the undercambered high pressure side has something to do with it too. I have some theories about the configuration of leading and trailing edges affect fin power but they are probably more about intuition than science. I hope you can get them into some juice to see how they do.
Good Surfin’, Rich
There’s a lot to templates, of course, but recently especially I’ve been thinking it is useless to extend the chord length in the lowest two inches of the fin. Let it stay the same chord as you have at two inches, or slightly shorter. Max the chord length out around 2 inches up, and then fade it into the tip. Makes a fin with good drive, hold, and less drag through turns especially. I was motivated by the Halcyon basic mental template, and have made my own that follow this basic concept (but are quite unlike the mentals near the tip). I came to this conclusion around the tenth fin I made for my system, playing with the different template components (rake, chord lengths at different depths),
You can note the chord length at each half inch of depth, and compare across fins. I bet Halcyon’s fins have longer chord lengths at two inches depth than more normal thruster fins.
Halcyon does more than just alter the basic template, of course…but I think that alone is a large factor.
Halcyon those fins are beauties! How did you get the feather (leaf?) design in there? Looks more like an inked design rather than fabric inlay. Really like how the rest of the fin is clear…
Fabulous work…
waxfoot
Hey Waxfoot,
All the cosmetic work is done with fabric. If you can zoom in on the photo you can see a watery effect in the clear area of the fin that’s done with a double layer of a very sheer gray fabric. The feather is fabric in between these two layers that fall centrally in the foil. In the attachment to this post the double layer effect in the body of the fin is less subtle because of the color. These fins are slightly small, buy the surfers request, than Tom’s fins.
Thanx for the kind words.
Good Surfin’, Rich
“Does anyone know anything about J. Johnstone? I ran into Matt Biolas on the way out. They both had LP finished boards in their hands. I asked Matt what’s up with the Surf Techs and told me that these were not Surf Techs. They are a new no core construction method and are using “America’s Cup” building techniques to build these boards. Matt introduced us. But, I didn’t want to hold them up. So, I just thought I’d ask here if anyone has checked out these boards”
I recall Greg Loehr mentioned on this forum a couple of months back that some big names in the industry were working on an s-core type project. Could this be it?
Tom,and Rich,
Nice report!
Sorry I haven’t been around Tom,been busy w/ life here lately.
Tom,are you talking about Pope’s new hollows?His are completely hollow ,no ribbing ,honeycomb,or foam.Greg Weaver was riding one up here and had positive results with them.Herb
I really don’t have alot of info. Matt introduced us and they showed me the boards. They had a white linear polyurethane finish and said J. Johnston on the rails. I asked Matt what’s up with the Surftechs and they said they were making these in Arizona using America’s Cup boat building technology. I said so you’re using pre-preg and a male mold and Jeff said yes. But, that’s all I’ve got.
I totally understand about the busy with life thing. Hope to see you at Plaskett Creek.
The Arizona clue may mean that Loehr’s involved.
Greg, you still on this Swaylocks thing?
