Thank you JRandy.
I was totally stuck in analysis paralysis, then remembered that i can make 2 more full size fins from this panel, anbd have 2 feet lof the 2x4 left over from the hull panel planks to make another hull matching panel, said F it, and out came the foiling tools.
The fin I cut from the panel a few days ago, was the white template on the far right that was over 6 inches deep. I measured 5 7/8" from the base drew a line then drew a new fin tip at that line and took a beltsander to the line.
Since the roving was sandwiched in between two cedar panels and neither side of that panel was really thick enough on its own if I were to completely sand one of the sides off to the roving center, I said F it again and decided to simply taper the thickness to the tip, then start foiling it, pretending the roving center was not there and not caring whether it would form the halo or not as it would if it were a center fin
The SOB is still 1/2 inch thick at its thickest along the base and is incredibly stiff. I'll aim for 7/16 or so, perhaps 3/8".
Rather than make the base of this fin fit super tightly and with maximum strength into the Probox insert, I am considering using the probox itself with NO insert, as a mold,and letting some epoxy with milled fibers form the mold around the base of the fin with a 6 degree cant and with trailing edge lining up with wing. No insert and not have any adjustment of cant or fore and aft.
The center roving when foiled as if it were not there, looks weird.
I've got to walk away from it for a bit. Fresh eye it later.
Decided to go ahead and get the base to fit within Probox insert. Might do the insertless mold if I want to change toe in, but This particular fin, I want the cant and fore and aft adjustment
Once the base fits nicely in to the insert, The insert itself Aids in the foiling of the rest of the fin.
Still a ways to go, and the SOB is still thick.
Totally flat inside.
It is Stiffer than the carbon TCredline with no glass on it, only in it.
I stripped the wax from the deck of this board the other day, and found that my right knee, which has slammed the deck of each and every board on my pop up for the last 35 years, had caused a slight soft spot to form on the deck in two spots. I added a lot of internal structure in an attempt to prevent this, but apparently not enough.
I used the poor man's vaccuum bag trick to cover the soft spot and a portion of the surrounding deck with two layers of 10oz cloth. At least I am guessing it is 10oz. All my cloth scraps were all too small and my Neighbor had some Bondo branded fiberglass bought at Home depot which I used.
The poor Man's vaccuum bag trick is basically wetting out the cloth fully, covering it with ziplock freezer bag plastic, and pushing out as much resin as possible towards the edges for a maximum fiber to resin ratio and pullng the cloth as tightly as possible as well. I've had good results using this method before on both rails and flat areas and this time was no different.
The One Sharky shaped twin fin sized cedar fin in posts above was made for my toe side rail, and the last time I surfed this board it was mostly my heel side rail that was engaged. However, I got one or two waves that peeled slow enough to allow a top turn, and the new cedar sharky shaped fin felt quite good when my toe side rail was engaged, So I decided to make another for my heel side rail to replace the TC redline fin.
I had also cut down one of Mr Miks' Gullwhale turbucle fins, whose based I broke riding my longboard, to shortboard size. Its base was reduced to fit tightly in a center probox, and the tab reinforced with some homemade carbon rods. This fin on a large speedy racey down the line day did nothing weird nor unexpected, and did not feel draggy. It only looks weird.
MrMik sent me several GW fins he broke when stress testing his designs, so I made two more to fit my rail Proboxes and one smaller center fin, and am very eager to try them, as His turbucled Gullwhale fin in my 9'7" traditional longboard, is simply magical.
iIhave cut out two more rail fins shaped more like a shark's pectoral fins rather than a dolphin dorsal fin a bit smaller than the other sharky style fins. I have only thickness tapered those so far, they remain unfoiled, and I might make them less deep as there is not really enough difference from the twin sharky fins.
i had forgotten that some 10 years ago I made these Bonzerish canted tab fins out of Lacewood for my 6'8" HWS, for use with a single fin, but I did not much like their feel. I think they look pretty neat installed this board as quad fins though. I have no intentions of trying them anytime soon though.
The unusually upright cedar twin fins were feeling very good underfoot, with a yellow MRMik 0.45 Gullwhale center fin cut down to fit the probox fin system.
Very quick, precise, almost twitchy, I was really starting to feel this board and fin combo, liking it more and more each wave during the Sergio swell, both frontside and backside.
Some guy on a HPLB dropped in on me without even looking, I should have yelled, but I should not have had to, but I intended to simply pass him and push him off, if required. But he turned before I could respond and I ran atop his board and jumped. I lost one of the cedar fins, and the other one is broken, but perhaps reparable.
The impact also broke the probox, but no other damage to board.
I have more proboxes, I could route it out and install anew. I am going to try rebuilding it first casting epoxy threads, with some techniques I developed reinforcing Mr Mik's 3d printed fin bases/ screw tabs. I will likely also make a jig for precisely drilling new grub screw holes and tapping them for 10-24 threads. To perhaps spread the load among more grub screws.
I have two more sharky cedar rail fins cut out and tapered, but not yet foiled. They are slightly less deep as the ones I lost and broke in the impact, but I might build the height up with more of a roving halo.
I can say I have no intention to go back to a lower aspect ratio/ more traditional fin with a raked tip. I am not even sure when that extra directional stability is required on a rail fin. I figure it is the job of the center fin. These thickly foiled higher aspect ratio fins as rail fins, had all the grip, and less drag and less resistance to directional changes, and were superior to every other fin setup I tried in this board by a good margin, though it did take some getting used to.
I also tried several sessions with 3 of Mr Mik's turbucled gullwhale fins cut down to reglar fin depth. The rail fins are 50/50 foils. It was a love/hate relationship. Loved them one session as they were quick and responsive and predictable once at speed, and another session in different conditions they were bizarre and drifty, and felt too small and imprecise especially at slower speeds. They also had a tendency to hook my leash and ruin the potential ride. They felt best at speed, and not pushed too hard though I did have a few turns where I did push hard and was impressed with the feel and the speed maintained and yet on another similar wave would blow the tail out trying the same style of turn.
I rode the 0.5 GW fins behind the sharky like cedar fins as a quad, and it felt pretty good one day with much more projection through and after a bottom turn than expected, yet the next day with same setup, I struggled as it felt like too much fin and too stiff. I turned it into a thruster on the beach and paddled back out and it clicked and I was on my 3rd session with this particular combo when the impact happened.
Very bummed I lost the sharky cedar fins, not only did I have a LOT of labor into them, but also as the impact very much shortened a session which had lots of potential. Also bummed that I do not have any replacements waiting to go, as they felt the best of any fins/ fin combo I have yet used in this board. I hope to have the board, and new cedar sharky twin size fins ready by mid week, and will make smaller center fins out of MrMik's GW fins that he intentionally broke stress testing, that just arrived today along with a bunch more GW fins with latest build method.
Bummer about the drop-in and fin damage. I hope the repairs go well and looking forward to the next ride report.
Be safe, have fun. -J
I forgot to mention I was using the white 8 degree probox inserts. I had been hoping they would crisp up the turning of the 50/50 foiled 0.5GW fins and left them in place when I installed the sharky cedar twins.
The one fin that broke but I still have, has the thick woven roving core, and a roving halo, but I only used one layer of 1.43 oz cloth on the exterior, which turned out to be nowhere near enough. The 3 or 4 layers of woven roving core was so stiff that glassing over a foil with more cloth would reduce water pressure inspired flex to perhaps nil, but I will definitely use more exterior glass on the next pair, as experiments on MrMik's larger single fins are leading me to lean towards less flex being better for my weight/intentions/style.
The holes I drilled into the broken probox are all at acute angles to the grubscrew, and the larger holes have smaller holes drilled at angles within those, for maximum grip/ mechanical tooth. I also run a sharp razor blade edge into the surface to make some deep valleys into the probox material for even more mechanical tooth. the repair might prove to be too weak, but it should not just Pop off due to lack of adhesion.
Getting resin deep in these tiny drilled holes is made much easier with the tiny pipe cleaner type brushes made for teeth, Den tek brushes sold at any drug store. The hair drier trick is also useful to pop stubborn bubbles and insure resin gets as deep as required.
I was planning on using System3 clear coat resin, which is extremely slow to set, and very thin viscosity, along with some milled FG fibers and then roving bridging the waxed grub screw. This particular epoxy resin has proven to stick to waxed glass much stronger than other epoxies, and I think its adhesion is superior to any other epoxy I have, or have used, so it should be the best choice I have to rebuild the broken grub screw area.
I have successfully cast epoxy threads before, on 3 or 4mm metric screws with a 0.5 pitch, so doing 10-24 threads should be much easier, although I will have to precisely drill/dremel out the very bottom of the hole then tap it.
With cast epoxy threads, there is absolutely no wobble between screw and the casting/mold, when reinserting the screw. No room for error and very easy to cross thread and ruin the cast threads. The angle one attempts to insert the screw needs to be overwhelmingly precise, which proved to be the downfall of the tiny fine thread metric cast epoxy threads.
The super high aspect ratio twinny rail fins are lively crisp and quick, and did not catch and hold onto my leash like the turbucled rail fins would. Those who can make their own fins should try something outside the traditional 'dol'fin shape with the aestheticaly pleasing exaggerated raked tip. The upwash and the rake of a lower aspect might be beneficial for propulsion on a fishtail, but without muscles pushing the raked fin tip to take advantage of that upwash, I am currently seeing the raked tip as unneeded drag providing extra resistance to directional changes, and see few places where this would actually be beneficial in most waves I encounter.
One day I will drag my camera behind the shortboard too. On the longboard, the single fins the visible tip vortex is more pronounced the more rake the fin has and the more rake the fin has the slower it is, and the longer the turning radius is. Mr Mik's deaweeder fin in my round pintail longboard, after so much riding his upright GW fin, made it feel like the tail was less round/ more of a pintail, and more stretched out. More self centering, but I was struggling on turns, expecting the board to come around quicker.
Some 6 months later.....
After losing 1, and breaking the other, of the first sharky cedar fin set, I was in a bit of a haste to finish the second set, and did not spend nearly enough time on the foil and was not really happy with their planshape or foil when they were finished.
My attempt to bridge the broken probox where the grub screw was ripped out when I lost the one fin running over the 'I didn't see you' drop in artist, was a failure. The epoxy I used attempting to rebuild the area around the grubscrew, some older clear coat system3, well I had just enough left in some small bottles for the small volume required for this task, but perhaps something happened in the year+ since I had last opened the containers. Anyway the carefully weighed and mixed epoxy, after two days obviously was not going to harden as it should, and out came the router and probox jigs, and I installed a New Probox.
Shortly after this was completed some 5 months ago, I Wound up taking a road trip with my 81 year old Dad across country, 2600 miles door to door, but drove ~4600 instead zigzaging out west, sight seeing for a week, and surfed only once on the East Coast over the winter. I was not really chasing it when there, there was certainly more opportunity to chase weather systems/conditions to get some quality glide time, but I was not on it. Awaiting groundswells and conditions a week out, south of Conception, is so much easier.
I rode the new sharky cedar fins In Patrick AFB in Florida on waist to chest high offshore short period not very impressive windswell midway in that 4 month journey. The HWS and new sharky cedar Fins felt very quick and very loose in what was mostly gutless dribble, but I was out of the water 2+ months at that point, overindulging in foodstuffs and beer and should likely have been on my Log, in retrospect.
Drove back across country about a month ago and have been scraping off rust, lots of it. I am Probably the heaviest and in the worst paddling shape of my life, but am off the beer and eating much wiser too.
I have gotten several sessions on my singlefin Log HWS, and this 6'11"#7 HWS with the newest sharky cedar rail fins, and am starting to get some flow and fitness back, and the last two days rode the new sharky cedar rail fins with both the 8 degree and then 6 degree inserts then back to 8, all with the 0.45 sized MrMik Gwhale turbucle fin in center Probox.
First the 6 degree inserts, it kept feeling like the board wanted to be turned flat, and when I allowed it to be flat turned on a lesser turn, would swing/pivot way too fast and draw these weird lines that irritated me greatly. The 8 degree inserts feel way way better when on rail, but The whole board is just too loose with this fin set up. Every hard turn and the board is turning in a way shorter arc than I had planned on, seemingly without losing any speed, and the second half of the turn is spent trying to maintain my footing/awkward recovery, rather than initiating the top turn where I had intended. I moved the 0.45GW fin back, moved the rail fins up and back and up again in teh 8 degree inserts, and pretty much just had to accept the fact I cannot turn this board as hard as I want to, and can, with these specific fins, and not have my legs collapse under me as the arc is too short and the G force too much, it just feels unnatural and likely looks worse. I Very much wonder what some uber fit rubber kneed ripper could do with such low drag fins that also have so little resistance to redirection once they figured out the new lines that could be taken.
These super high aspect ratio fins seem to present little to no resistance to changing direction, and it is not so easy to get used to when really pushing hard. If one is not really pushing hard, then their low drag speedy and crisp nature is quite enjoyable.
If one were to make a vehicle driving comparison regarding turning these fins compared to more traditionally raked dol-fins, it would be like a sports car that was 3 full turns of the wheel lock to lock, then driving the same vehicle the next day and only 2 full turns turned the wheels the same amount. It would be hard to do 10 laps on the 3 turn lock to lock dolfin then change the steering gear, and then do the next 10 laps with 2 full turns lock to lock superHAR fin. The straight aways the sports car would feel like it had noticeably more torque though, and then find weaker brakes for that upcoming hairpin. Thrilling, but lap times would likely suffer until one got very used to it.
The first set of slightly larger sharky cedar fins(RIP) felt way better, their tips were slightly behind the trailing edge of the base, but the newer smaller ones are not. I did not have enough fin panel remaining to work with, and the halo added after the fact, did not make up for it as I was hoping, once I foiled the halo.
The yellow turbucle center fin, well these things in the longboard can achieve much higher AOA before they stall and when they do it is gradual and predictable and seemingly much less drag in full stall, so these sharky high Aspect ratio cedar fins and this 0.45GW center fin is simply too loose, too pivotal, the board pivots on teh inside fin, the Turbucle fin has no issues slightly stalled in such a position and the board swings up the face so much faster than expected/desired when I push a hard bottom turn. I love a hard bottom turn, often get compliments on them when I ride my log or this 6'11". My Log I widen my stance and have mostly gotten used to a shorter duration higher yield bottom with MrMik's Gwhale turbucle fin but I can still overrotate and find myself with not enough time to get the 25Lb board on the opposite rail.
I do not feel like I am surfing well on my 6'11" with this fin set up, when I am pushing hard, as I am drawing out longer lines in my mind. The board's turning radius with these fins, has shortened that line way too much . I kept feeling That it is throwing off my timing, and I simply do not currently have enough leg power to handle the g forces that these fins can allow in that shortened turning radius, and practically no fin resistance to that turning. the resistace is sinking the rail only, it feels like. I can't yet take advantage of the difference, and do not know if I want to learn to adjust to this new feel, I mean I ain't no spring chicken. I just want to go fast turn hard. First part is there, second part I've been going over the handlebars.
So this extreme high aspect ratio rail fin experiment has been enlightening, and I think one must bounce off the extremes to find some happy middle ground, but I also find myself reluctant to reintroduce a traditionally raked factor to fins on this board, as the low drag quick accellerating nature of such a high aspect ratio is a bit addicting. Especially on my 9'7" single fin, but that of course is an entirely different style of surfing and that board's top speed with so much surface area, tail rocker, and soft rails is inherently limited, even with a much lower drag fin.
I've made a new fin panel for the next sets of rail fins. I Liked the looks and flex and relative ease of prepping then laying up 3 layers of woven roving when making a panel, even if it is not quite fully saturated as desired, so three layers were recently laminated to waxed glass with 5/16" of WRCedar planks left over from the board build weighted atop. I can easily make 4 thick fins with a lower aspect ratio or 6 high aspect ratio flat sided fins from this panel, but so far have not busted out the new cardboard for making new potential templates for what comes next.
Part of me wants to replicate the First set of fins that I broke/lost, as they seemed to impart more directional stability, and somewhat prevent the extreme overrotation that occurs with these second set of fins.
Part of me wants to build a lower aspect ratio center fin with these low drag super HAR rail fins. I like the very low drag high responsiveness of these rail fins, there is absolutely no signs that they are drifty or not enough fin, I just miss the self centering and stabilization and longer turning radius, that drag and resistance imparted with the raked tips and a lower aspect ratio helping rail and fin to work together in a more familiar manner.
Wondering if I can gain the control I want keeping these rail fins and changing up the center fin, and not have the board feel too draggy, in comparison to the 0.45GW fin. I got those pesky Quad boxes too, to confuse the matter further too.
Wish making fin panels and foiling fins and dialing them to fit properly, was less time consuming, or I was flush with cash, and there were more untraditional looking fins I could experiment with, and be emotionally removed from the effort of designing and making them. and thus be less inclined to want like them by default.
Love the board, the fins? Not so much. I like the execution but the design of the fins might be partially to blame for the handling issues you describe.
You've explored the outer limits on those and it might be time to settle in on something more tired and true/conventional. On the damaged box thing - I would just use some thin plastic shim material and jam the fins in place. Skip the screws.
A basic set of sidebites and something like a 7"- 8" conventionally raked/foiled center fin might be your best bet as far as further experimentation(?) In the photo it looks to me as if the forward fins are too large and vertical and the rear fin too small. I am aware of the tuburcle theory but haven't tried one. I'll pass judgement on that aspect of it.
I know the sharky fin planshape would raise eyebrows. They are just too far outside what we have been conditioned to see on the bottom of surfboards, and the graceful tapering sweep of a traditional dol-fin and its obvious functionality cannot be denied.
Riding the Wavegrinder WG2 with its high aspect an winglet on my traditional 9'7" was quite surprising. I expected to hate it and quickly mail it off to some one else, but instead had my mind blown, even with its limitations, namely the locked in tracking feel in certain parts of the wave when going much faster than expected, and the overflexing unseating the rail at the end of frontside bottom turns.
MrMik's high aspect 3Dprinted turbucled fins on my Longboard proved to turn better without any of the tracking and are a lot quicker than the traditional dol-fin. Win Win. When I tried his even higher aspect ratio Gwhale fin and found it had all the quickness, if not more, of the WG2 HAR, and all the forgiving and loose nature of turbucles I was ,and still am, a bit blown away. His HAR GW fin design in my 9'7" is such an incredible feel and enhancement, I had to extend my experiments in fin design to multifin boards. I cannot shape turbucles with any precision and maintain some semblence of sanity, so I went with high aspect ratio and a narrow thin tip to have the minimum tip vortex possible, without the inclusion of turbucles.
Yep, there are issues, these fins are too pivotal, the nose swings in turns way faster than expected, but in terms of speed and accelleration, well these characteristics are undeniable, and I am very glad I tried this, and to try it, I had to make them, as I have not been yet able to convince MrMik to put his design efforts towards multifin boards, and I have seen nothing on the market remotely close.
So working within the adjustable abilities of the 5 proboxes on this board, I will continue to experiment and likely have very Odd looking fins well outside traditional norms,. If I had 3 TC Redlines, I know I could pretty much have a very predictable and solid fun board in almost any conditions, but then I learn nothing, and while I have to give a big thanks and nod to tradition, nothing new is learned by a 'this is the way we've always done it' attitude and i have a whole bunch of 'the emperor wears no clothes' in my system.
The center probox is too far back for a traditional 2+1. I almost included a bahne center box, but decided against early on. My first HWS is a similar 6'8" double bump round Pin with a large single fin box, and I rode it as a 2+1 for a few years, making many center and rail fins, dialing in a feel, but when I retried traditional rail fins with a smaller center fin, I realized I simply liked that feel better in most conditions. The 6'8" is still a fully functional platform, but I made it for my 30 year old self, not a 47 year old, so the 6'11" has significantly more volume and refinements on the basic design and significantly different internal structure..
Wedging something in the Probox to eliminate the grub screw, is not an idea I like. The inserts are tapered, the grub screws push both fin and insert into the board, and I am pretty adamant about a tight footbone to finbone connection. So much so that when I do have a design and cant and fore aft location rewally dialed in, I am going to mold the bases for insertless design. When I ordered 5 proboxes and a bunch of different inserts, I received 12 proboxes with the different inserts I ordered, so routing out the broken one and any future ones is always an option. A jig to hold a drill bit and a tap are in my pans to add extra grub screws for more fin retention strength of the proboxes.
The overrotation control problems with these pectoral shark fins was not something I had really considered when the pencil was taken to cardboard, after watching videos of silky sharks in pre attack mode. I expected the center fin to provide that resistance to overrotate/swing too quickly, but the turbucled center fin I am using is also so pivotal and easy going that it does not provide that control.
The first 'sharky' set which was broke/lost being So different in this overrotation feel is surprising, as there is not an incredible amount of visual difference when they are held together. Some of that difference has to be related to my 4 month hiatus of surfing this winter and the weight gain, so I am not quite ready to write off these latest sharky fins, and will keep riding them until I have finished something new to install. I have dozens of traditional fins which fit proboxes but extremely little desire to bo back to them. I do have a slightly larger turbucled center fin which might help stiffen it up, or perhaps I will learn to not overrotate with more time. The overrotation might be solved with a regular thruster center fin and i can keep the low drag sharky rail fins. Time and experimentation will tell.
The New fin panel, well the flat sides will not be revealing any of the beautiful cedar below through 3 layers of woven roving, but they should be a lot less time consuming to achieve a well fitting fin, and most of the dust made when foiling, will be cedar, instead of fiberglass. I will continue along these High aspect ratio lines, and seek to find a way to lay my 210+ Lbs into into turns and wind up where I intended, and if that returns me to traditional dol-fin designs, then so be it. HAR is low drag, and it is not easy to give this up, even if fears of overrotation laying it on rail, leads leads me to surf like one would downhill skateboard in the rain. No denying the thrill in that.
Everything you’ve done here is very creative and work well done. Including the repairs. But, I am especially impressed with your ability to refine the details of the shaping that you have put into this board. Refined bottom contours and rail. Pleasing to the eye outline as well. Refining a shape in wood is not as easy as people think. Nicely done. Lowel