Loosest sup I've ever ridden

So ive been supping a while and tried most brands and sizes of boards from 82l and 7'2 to 145l and 10'0 but today was a new revelation. A local low shaper in Nz came up with this sup line and one came up locally to try- it's 7'6 x 27.5 x 100.5l. My first wave test was going to be a challenge, with a big swell blip, heaving offshore wind and OH waves. First wave was a big grip challenge, compared to my normal pin tail sups. It was soo Loose!
Came in and went to another beach where the swell was only shoulder but peaky, on the second wave I did this crazy top turn that just cut so hard it felt like it was dragging me behind- the board just wanted tighter and tighter hacks. So I pushed a bit more and holy crap- probably the tightest turns I think I've ever done. I was just getting wave after wave. The board is crazy fast, crazy agile, feels very light. At the end of the sesh it was blowing me away.
SO- what's different about it? There's a couple Of unique design characteristics which must be playing in to it.
1). it has a hard / very sharp edged rail most of the length of the board! Never had a board like it. 2). the concaves are deep and nuts- single to heavy double from mid board! Like a 4mm maybe double from mid board out through the tail. 3). tail rocker, it really kicks up at the end. Taking some getting used to.
4). wide heavy rocker nose flip, then chunky mod board hit thinned out and rockered tail. 5). Any seen the multiple centre fin slots before? I stuck the fin in the middle where I assume neutral was? Further forward would've been crazy loose!

Interested to hear feedback from the more knowledgeable design people here as to how those are playing the parts on this.

As a kiwi I've never seen them but I haven't been in any sup stores.

Interesting shape and I've learnt to be open minded when something different perform.

I found the video and a face book page.

?si=228I4TSyws0opYdI

What's different for me though @Colas, is that I've owned (and own) a 7'2 hypernut and that is nothing like this. The hypernut was not super loose or pivotal and I could hold it relatively well on a bigger wave. This board was crazy different, loose as a bloody goose. So agile I had a hard time learning how to control it and hold it on the wave, it just wants to release left; right and centre. The pics don't properly show how much the tail kicks up at the end.
It was honestly so different to anything I've ever ridden. Just trying to figure out what is is exactly which is causing it to such an effect.
My hunch is the hard rail for most of the board, the heavy double concave from mid board and the thinned / rocketed tail.

Judging where my centre fin was (middle of the 3x different fin positions), not sure whether this is the 'normal' place or whether at the back of the box is normal? As that would also contribute?

Select to expand quote

colas said..

thegreatsup said..
compared to my normal pin tail sups.

Well, I guess you discovered why boards for weak waves have wide nose and tails, the "Tomo" shapes pushing it to the extreme.

They give you the instant acceleration and speed that is the fuel for looseness and turns in fun conditions (as opposed to survival ones :-) ).

Hi Colas, I've been riding a JP Slate 7'2 for 6 or 7 years now (i'm85kg - it's a small board for me but quite fine to paddle around); it has the fins set quite wide which makes it a really drivey board - very fast down the line and locked in during bigger surf (double over head). However, in smaller surf I run it as a thruster and it becomes lively and pivoty - good for 1-2 foot. In overhead surf it becomes too loose as a thruster. I guess my question is about how much do the fins play a part in the shape? I have been reading your posts for a long time and respect your input - I am just experiencing these boards differently.
many thanks

Select to expand quote

barbarian said..
I guess my question is about how much do the fins play a part in the shape?

A lot!

For widish-tailed thrusters, picture the board rolling in a turn: the tail rail sinks, but the center fins become lifted towards the surface, where it has less grip, because it is far from the rail. If you pay attention, you can feel the slight tail slide (before a full fin release) it generates in turns, as opposed to the quad where the inner rear fin bites deep into the water with the rail.

This phenomenon is less noticeable with narrow tails, where the center fin is not moved a lot upwards when rolling.

This slight tail release is what helps a wide-tailed thruster feel loose in weak surf, but can spinout in faster/hollower surf.
Quads can shine in weak surf too, but the rider will have to use the grip of the quad to generate more speed than with a thruster, getting looseness via speed instead.

The JP Slate has a very peculiar fin setup, with the rear quads very close to the rail and far back, this promotes a very drivey, "locked in" feel, where you have to engage aggressively for rail-to-rail turns. And as a thruster, you can see how much the center fin will get lifted as it is very far from the rails due to the very wide tail, providing smoothness, but loosing grip in bigger surf.



It would be interesting to try to have rear boxes placed in a McKee setup (rear boxes closer together), for instance along the channel ridges, it could provide a quad setup that could work in all conditions.

mckeesurf.com/index.php/fin-direction-graphic/?nbsp

Example of a McKee setup:




What you can try on your slate is to use a 5 fin setup: find the smallest fins you can fin (3.5" trailers?) and use them as rear quads + another one in the center both to keep a reasonable total amount of grip , and smooth the rail to rail by distributing more the fin areas.


.Here is one of my small wave SUP board with a 5 C-Drive setup:
The rears were their smallest size, the "Grommet".

Yeah the Skate essentially has a hard rail the whole way too...The hard edge gives release and allows it to sit up high in the water, which gives it plenty of speed. The compromise is that it then usually loses drive.

My custom Sunova Longboard sup has a crispier rail along most of the rail to add sensitivity - compared to the stock (Sunova Surf 10 footer) board.

As we all know all of this stuff is a compromise.

I think the centre fin at the rear most position is where i'd put it for head high stuff. For smaller, i'd then move it forward.

Agree with Colas on thrusters usually being looser than quad. That's why I like thrusters typically as I have found most quads feel too locked in for me. It can be tweaked by using way smaller rears or sanding/taking the tips off the rear fins. Colas has shown this on some quobba posts before.

McKee set ups are meant to give the best of both.... The new Kalama longboard sups have a fin set up like that.