FUP – fin options

LOGO_MULTYSYSTEMWith an unknown design like “the FUP”, I figured as many fin options as possible is best. But, the issue, or question is “what positions”?

So, to start, it has to have thruster option, so I went and checked what I’ve been using against the McKee M5.

I’ve had my centre at 3 3/4, sides at 11 3/8 (with 1/4 toe in)

Looking at the McKee formula for the 6’3″ and 6’6″ (i.e. the FUP is 6’5″):

Centre – 3 3/8 (for the 6’3″) and 3 7/16 (for the 6’6″) … mine at 3 12/16

Sides – 11 1/16 (for the 6’3″) and 11 5/16 (for the 6’6″) … mine at 11 6/16

So, I figured I will stick with my centre fin position (i.e. one less variable), and it was more the “quad” linkage I was chasing so the centre fin for Thruster should be OK.

For the sides, with only 1/16″ difference, and planning to use Gearbox fin system, I will have fore and aft movement, so can tweak once in use. Cool.

Now, the “quad” option and the rear fins … McKee has them at:

5 3/16 for he 6’3″ and 5 5/16 for the 6’6″ … so, only 2 /16 or 1/8 between the two, which again, can be adjusted with fore and aft movement by using Gearbox

So, I’ve decided to place them at 5 5/16.

Now, the issue of “Toe-In” … Mckee has his layout guide, which uses the “measure x off the nose” method … which I do not use. So, a bit of time on swaylocks has been thinking if the fronts finsa are going to be 1/4 toe in, then the rears can go in at 1/8″ toe in … this seemed to be common option.

So, that’s it done, right?

Nope. Next issue is fin cant …

Again, looking at the McKee layout guide, he uses 92.5 for the back and 96 for the front, measured off the horizontal.

I have been using between 96 and 98 for my sides on thrusters, and feel 7 is about ideal. So am going to stick with that … which, then means, the rear quads need to be less, so using the mckee layout and research on swayslocks, I’ve decided to go 4 for the rear quads.

Now, I should also mention the “other school” of thought with quad fin placement being more “rail centric” … and using say 1 1/18 off the rail for all fins. I’ve decided to use the mckee “width between rear fins” method, because I am a traditional thruster surfer, and my research seems to indicate the mckee layout suits that transition better. The front fins will be 1 1/18 off the rail though. So, after all that thought process, whether good or bad, the final details I’m going to use are:

Front Fins – 1 1/8 off rail, 11 3/8 from tail with 1/4 toe and 7.5 cant

Rear Fins – 5 3/4 between, 5 5/16 from tail with 1/8 toe and 4 cant

Centre – 3 3/8 from the tail (but, thinking about using a fin box for more options!)




FUP Update

After I posted yesterday (i.e. re: “the FUP”), I decided to seek input from as many people as possible. So, I posted on a couple of surfboard design and construction forums, namely sanded and swaylocks; you can see the ‘discussion’ about the FUP on those forums here and here. I also shared a link via my facebook and twitter accounts with a few comments being received overnight (thanks crouch, JJ & digger) 😉

With a cool night and noise already in our neighbourhood (happy new year everyone!), I decided to get a ‘feel’ for “the FUP”, and well, one thing lead to another and by the time 2015 came around I was covered in foam dust and had hit the wall. I did manage to run a tape measure, layout square and calipers over it, and found out she is actually:

Length – 6’5″


@ centre – 18 3/4

1′ off nose – 11 3/4

1′ off tail – 14

Thickness – 2 5/8


Nose – 4 3/4

1′ off nose – 1 9/16

2′ off nose – 6/16

2′ off tail – 1/4

1′ off tail – 3/4

Tail – 2 5/16

So, here’s a couple of video clips I shot this morning which might help to show the “flow” of the concave depth and current status of the blank:

Here are some progress shots too:


the FUP - deck side outline (316x1024)

FOIL – deck up:

the FUP - deck up foil (1024x175)

FOIL – bottom up:

the FUP - bottom up foil (1024x170)

And, a few others while she was laying in the stands:

the FUP - side 3 (768x1024) the FUP - side 2(1024x768) the FUP - side (1024x 768)

RIDE REPORT – my predictions

So, now having handled the blank, and “scrubbed” it to an almost finished state, I have a few thoughts about how it may go …

1. The deep double has the rails at an acute angle, which I suspect will give “bite” but also instability; could ‘catch’ quite easily especially in bottom turns.

2. Down the line speed, at potentially the expense of handing with it tending to “track” … but, it could be a good hollow wave board due to the rail bite and straight through water flow.

3. An uncertainty in handling with the ‘tri hull’ created by the rails (as outside hulls) and the stringer … bit like a tri hull catamaran. While it “should” be stable, I think what is likely to happen is the water flowing at angles across the bottom will became turbulent, especially as the water crosses over the stringer section. When on full rail, it won’t impact, but as the board comes back to a more level point, it will “catch” and bog, which will create a point from rail to rail that is unstable or unpredictable.

4. It will not like fat, flat or mushy waves … will need some shape (i.e. curve) in the face of the wave to engage the rails and that acute angle from the deep double.

5. Will need fin options to fine tune it, so am thinking to put in a small single fin box (for maximum adjustment fore and aft) plus option of a larger back fin, with a mckee 5 fin system layout for the other 4 fins, so it can be ridden as both a quad and thruster. Might be cool to try with a big single and some side bites 🙂

OK, that’s my take. What do YOU think?


She’s been known to visit from time to time (i.e. that special little lady; the fuck up fairy), but never like this … well, not around here …

So, here’s the story so far:

I decided to get two blanks cut to work on over the Christmas / New Year break. One, a remake of the Forty One Two – winter version (i.e. my current all rounder) and the other, an evolution of the Nineteen Ninety Seven (i.e. the minimal that started this journey) … so I sent the files off for cutting, and knowing the rush before Christmas had no expectations they would arrive quickly. So, about a week or 10 days later I went to collect the first one that made it into the cutting queue; the all rounder. Sweet.

Then, about a week later, I went to collect the minimal. Oops… there was a mix up, and somehow the all rounder was cut again. Ok, no worries … BUT …

There was a difference, a BIG difference … and that is where this part of the story gets interesting.

Note: Before we go any further, as you may know, I get my blanks cut and other supplies from Shapers. So, with this little, ah, glitch (see below), I just want to point out they have been on top of it, and have actually given me the second ‘glitch’ blank to play with, at no charge. It’s sort of become a talking point, and as you’ll read below, they, like you, have input into writing the rest of the story.

It appears there was a ‘glitch’ with the file sent to the machine. Now, remember, this was or should be exactly the same file (i.e. the same file was accidentally sent for cutting twice), so somewhere along the process, when it’s been cut the second time it has developed a “glitch”, and the end result, is what I’m calling “The FUP”

So, here she is in all her glory:

The FUP - Single and Double at Centre (close up) (1024x768)

That is at the CENTRE of board … Yes, you read that correctly … THE CENTRE!

Here is a close up of the depth of that double concave:

The FUP - Double Concave at Centre(1024x768)

Not sure if you can see it clearly, but that ruler is showing the depth at 1/2 of an inch!

And, remember that is at the centre of the board …

Here is another picture of it, this one taken from a wider angle:

The FUP - Single and Double at Centre (1024x768)

So, as you can see, the whole mid section of the board has some seriously deep concave(s) … the single concave depth, as measured by using a straight edge from rail to rail and then measuring down to the stringer is 3/16. That runs from approx. 12 inches off the tail right through the centre of the board and up to approx 24 inches off the nose.

The Double Concave depth(s), as measured using a straight edge laying from rail to rail and then measuring down to the deepest point in the double, are:

@ 12 inches off the tail – 3/16 of an inch

@ 18 inches off the tail – 1/4 of an inch

@ 24 inches off the tail – 6 / 16 of an inch

@ centre – 1/2 of an inch

The concave(s) (i.e. single and double) at the tail, through the 12 inches to 18 inches off the tail (i.e. between the fins) are fairly, ah, “standard” as you can see from this picture below:

The FUP - Single and Double at 12 off tail (1024x768)

As mentioned above, the crew at Shapers have given the cut blank to me at no charge. So, I’ve decided to make it, and see how it goes … Yep, you heard right, it’s going to be made, and ridden, but I’m not sure of a few things and need YOUR help. Yes, you … so, my questions for you:

1. Do you think I should reduce some of that double concave through the centre of the board? If so …

a) … should I take it out by increasing the single concave by shaving down the stringer, (i.e. flatter rocker at stringer), or

b) … should I take down the rails (i.e. flatter rocker at the rail), or

c) … a combination of both, and if so, how much off each?

2. How do you think this board will go?

a) … as is without any adjustment to the double concave as per above, and

b) … with your suggested refinements from above.

3. What fin configuration should go in this board?

a) … standard thruster, or

b) … standard quad, and if so, mckee set out?

c) … a five fin combo?

d) … what about a single fin box for added variety?

4. Any other thoughts?