Looks brilliant Rohan, can’t wait for the ride report. Something tells me that it’s unique design means it will be great in certain conditions.
Why that particular fins shape ?
Thanks Surffoils.
The fin shape is one of the latest I’ve made and haven’t tried yet. The shape is designed to reduce the “wing tip vortices” that occur at the tip of the fin. These vortices are created during a turn when the water under high pressure on one side of the fin “spills” over at the tip of the fin onto the low pressure side.
Its shape will create what is called a “bell shaped spanload”, in aeronautical terms, instead of the usual “parabolic spanload”. Reducing the amount of lift just at the tip of the fin will reduce the pressure differential at the tip and minimise the “spillover” and subsequent vortices that produce drag. Basically it’s a flat winglet.
Surfed it today in shifting 3’-4’ beach breaks, which were hardly ideal conditions for such a design, and can report the following.
It paddled and duck dived (it didn’t) like a longboard. I couldn’t muscle it around at all like a shortboard, despite it being less than 6’ in length. The waves didn’t allow me to test it properly in trim mode, so I don’t know if it will hold a line how I want it to. It’s too unstable/unpredictable at the moment in turns with the tail thickness and roll. My experience with surfing longboards is very, very limited so that obviously doesn’t help the situation.
It definitely needs some work. So back to the drawing board with a series of planned revisions/responses with retesting in between.
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Add side fin plugs, approximately in line with the rear main fin, with minimum toe in, and maybe even negative cant angle (angled toward the rear main fin).
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Build a very large D fin for it.
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Put a fin box in the deck, flip it over and surf it upside down (the deck only has about 10mm roll compared the bottom which has around 25mm).
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Learn to surf a longboard properly (maybe I should move this to step 1.)
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Send it up to Surffoils for him to deal with.
Hahaha !
Send it up ! Seriously I’d love it, Im already thinking of customising it.
But you’ve got so much scope to do it your way.
But should you get bored of the Invisible Longboard, please send it to me first , all costs covered.
Wait for a decent day.
Also how are you attending to ride it? In trim or off the tail?
Yeah, right? Tail or trim?
Going through the thread, there’s been like 3 different fins in the pictures. I like the third one but to me, I’d move it all the way forward and try that. Looking at the bottom and the rails, it appears to me it’s going to surf like a displacement hull mixed with a kayak. So, you might find a nice home for it in steep, zippy waves. However, with that rocker, steep zippy waves might not be desirable.
You keep saying you don’t have that much experience with a longboard yet you wanted to build a short one? Tricky.
Also, there is a gigantic difference between riding a longboard and riding a longboard with a rolled bottom. For your board, I’d actually try turning it from the middle of the board, using the rail.
Also, I know it sounds odd but if I was testing a board out like that, I’d want to try it on a knee-waist high day first, just to mess around and feel it out.
Just looking at it, I would think… set the rail and surf it up on the nose. Like front third of the board. Who knows! Haha.
I would love to ride it for a month or so tho. A good amount of time to sort it out.
Thanks heaps for the advice guys. I need to be bit more selectiive about where to try it next, and how I try to surf it.
Rail, not tail will need to be my mantra with this one.
I’ve owned and ridden a few of the original hollow 18, 16 and 12 foot hollow ply boards that have a constant rail to rail roll from nose to tail. They’re a bitch when they’re full of water too. I nearly left one of the beach because of exhaustion from paddling it. The old guys were tough.
They are unstable when ridden from the middle and were a lot easier to turn by sinking the tail and resetting the line.