Multi fin selection for onshore

grantmac017 · Joined: 04 Aug 2016 Posts: 946

Currently using a 95L Quad LS (fairly flat rocker) for general blasting/side/onshore wave duties. I'm getting the feeling that I'm quite underfinned. Fast off the wind or down a wave but nearly zero back foot pressure and tends to spin easily. Moved the front strap and mast base back which helped but not 100%. Not a lot of room to move the fins either.
Standard MFC 350 fronts and 15.5cm K4 Flex rears.
I'm ~185# and mostly on 4.2-5.8

Considering a matched set of K4s in a stiffer and slightly larger size. Suggestions appreciated.

Thanks,
Grant

dllee · Joined: 03 Jul 2009 Posts: 5329 Location: East Bay

Onshore wind and windwaves require the biggest fin sets and lots of sailpower.
Two 15 rears should be too small for those conditions.
Tri fin setup is usually preferred for onshore winds.
10-12 front fins contribute very little to holding power while sailing straight.
Flex or stiff is personal and up for debate.
Bigger rears the first option.

manuel · Joined: 08 Oct 2007 Posts: 1158

Had similar experience. Used 2x16 flexies with 11s, stock was 13+11.
It's too much with 4.5 but fine with 5.0.
I tried 16's alone but lost low-end drive and low-speed planing.

It's the best feeling on a wave. Old school single wave boards were better for onshore bump & jump because they had the control with some drive. Multi-fin lose drive over wave fun!

http://www.iwindsurf.com/forums/viewtopic.php?t=30545

grantmac017 · Joined: 04 Aug 2016 Posts: 946

I believe my fronts are only a 9cm when I measured, I'll recheck.

I've considered using it as a twin but we get quite a bit of chop and I'd like the security. A more powerful 16.5-17 set of rears might play well with the fronts or perhaps as twins.
I can grind upwind planing with the rail which is I believe not an unusual technique for a quad, but I'd definitely like some speed upwind.
If I order from K4 (likely) there are a lot of options which are difficultto chose from. Also a set of larger asymmetrical fronts would be an cheap experiment.

manuel · Joined: 08 Oct 2007 Posts: 1158

I have a Kode wave twin, I run 2x16.5. Zero issues. It shows that some boards have more natural drive and willing to keep going even at slower speeds.

On the quad lowering the front killed the drive and 16x8 didn't work. But it may not be the case for your board. Check forums for your specific boards and sail size.

U2U2U2 · Posted: Tue Jun 04, 2019 9:25 am Post subject:

The super stiff versions.
Leon and Scorcher

https://www.k4fins.com/fin-guide/

grantmac017 · Joined: 04 Aug 2016 Posts: 946

isobars · Joined: 12 Dec 1999 Posts: 20935

I sail in onshore conditions 100% of the time, and the OP's experience with his quad mimicked my trial on one. Demoed a tri, absolutely loved it, and quickly bought three sizes of them. The quad shaper and Big Winds' WSing experts told me quads and tris are very different animals, requiring very different techniques. The Big Winds guys asked whether I really wanted to learn how to sail again, to which my answer was, "Hell, no. I don't want to have to look down to see which board I'm on every time I want to point, jibe, or slash."

grantmac017 · Joined: 04 Aug 2016 Posts: 946

This is about sailing quads in onshore conditions, not tris in the Gorge (which isn't onshore wave).

dllee · Joined: 03 Jul 2009 Posts: 5329 Location: East Bay

Regardless, of who says what for why, fact remains a bigger rear is needed, stiff or medium depending on preference.
Sides on a quad help add a pivot point, similar to wings and curve spots.
Placement of fins in quad usually forbid use of only bigger rear fins, so 4 is needed to match the outline, rocket, thickness flow, and strap placement.
Style and body weight has huge bearings on fin setup needed. Nobody can really judge exard.actly which fin is needed.
Experimentation and experience is the final factors.
That's exactly why lots of sailor choose a tri or single fin bo