Latest Progress on CUTAWAY DESIGN
A lot of work has been going on in the background on our experiments with extreme cutaways on some of our design. This is the latest update on our progress!
Latest Progress on CUTAWAY DESIGN
Things have progressed very quickly with the design process for the idea of a fin design with an extreme cutaway. Hopefully, this post will bring everyone up to speed with where we are in the process.
But first, we need to introduce a new word to our vocabulary as we will be using it moving forward with this new design concept. The new word is "KAHI", which is Hawaiian for "CUT", it is a nice compact word plus there does not appear to be an exact match for a word meaning "cutaway", so we will start using this word to refer to fins featuring this new cutaway design as it will extend over several different fin designs.
The first version using the KAHI is the A4C-500CK center fin design. This takes the existing A4C-500 template and adds the KAHI. Making this change to this fin has turned it into an incredible center fin. Testing has blown the thruster surfer's minds. Most of the testing has been done with either the A4C or XPD2 side fins, and it has worked equally well with either. The consensus is that using this center fin makes a thruster set feel and behave more like a quad. The center fin creates very little drag through a turn like a typical thruster center fin. This is largely due to the reduced base and the fact that the effective part of the fin is much higher off the bottom of the board. The feeling is that this fin is a game-changer for a thruster!
This template has undergone a slight tweak since this photo was taken, the KAHI is now a little deeper vertically.
The second fin to introduce is the new Q2 center fin, which will replace the existing one in the lineup. This new center fin - Q2-463CK is a very similar outline to the original but now incorporates the KAHI cutaway. This modernizes the fin and adds to its versatility, allowing it to be used with other templates if needed.
The JIB series now has a new center fin design as well, the JIB-538C v10, this is the latest version of the cutaway. The height of the fin has been increased to compensate for the loss of area due to the cutaway. This new template has been testing well when combined with the JIB-513 v10 side fins.
After making several modifications to existing designs and working on the JIB series we got to thinking about where we could take the KAHI concept, so naturally, we decided we needed a KAHI range that is completely different utilizing a more extreme version of the KAHI.
The first of these designs is yet another center fin, the KAHI-500C that pushes the cutaway to the extreme and also adds a new blade shape that has more area. The fin is more raked than the JIB series that will give it better projection.
It has a leading-edge outline that is loosely based on the same rake as the A4C template, but with the curve being flattened in the bottom half of the fin. This fin is currently being tested in combination with the JIB-513 and it has proven to work well. It is especially good at pumping a board down the line and in smaller surf gives the board more of a quad feel when ridden as a thruster.
We have now also made up a set of KAHI-500 side fins that are being tested with the newer fins described below.
Next up the introduction of both the JIB and KAHI designs has prompted us to take a look at whether the KAHI concept could successfully be applied to something like a Hammer design. The idea being that this would allow for a fin design that had extreme hold for the size due to the blade. This would then make for an ideal back fin in a quad setup, whether in combination with another KAHI design or some other fin design. Through removal of the base area and focusing all of the fins abilities into the blade, it will provide a lot of drive and holding power, without impacting the looseness of the setup.
We started with the H6 template and applied a KAHI to it to see what we type of outline we could create.
We are super excited with what we have created, this is one cool looking fin and it ticks all of the boxes for the goals of a fin of this design. While it is another generation of our Hammer design we chose not to call it a Hammer instead it is another KAHI variant - the KAHI-400H v4!
We'll attempt to try and describe the foils used on this fin but it is going to be difficult as it has a very different HOLOFOIL on the inside face. Plus the cutaway is not foiled away as one would expect, instead, the inside face of the cutaway is left blunt to allow the water to flow off the foil. The bottom edge of the blade has been scalloped away to form a hollow foil that is more open along the bottom, forcing the water to flow more off the bottom than the top of the blade.
This is a very unusual looking fin, much like most of our fins, but for anyone familiar with our existing Hammer designs you can see its heritage!
We have done one additional design specifically as a rear fin for a quad setup. This one is loosely based on our LS template that we have had around for a long time. It is very similar to the Hammer based version, but with the leading bulb removed. This version has an even more unusual foil than the Hammer version. Moving forward this new foil is going to be used for the Hammer based version as well, now that we have figured it out.
This photo should provide a better idea as to how this new fin is foiled as it will be hard to describe the foiling. Hopefully, this will give some idea as to the foiling of the fin. Essentially the cutaway has not been foiled away to allow the water to flow off the fin unhindered.
These new KAHI based fins are turning out to be a revelation as they work remarkably well with plenty of power and hold!