Quad rear fin cant angle issue

Hey guys,

Glassed on some quads last night in the mckee configuration and noticed that my heel side rear fin has more cant than the opposing fin. It’s roughly parallel to the cant on the front fin (~6.5 deg rather than the intended 4 deg, not sure how I missed that before laying up glass AND hotcoating). You think I should just roll with it or cut it off and reset? Anyone have experience with quad setups with parallel cants? My thinking is that it may actually be beneficial for engaging frontside rail turns (important to me) but may lack drive backside. 

Also, something I read on here a few years ago keeps popping into my head: “why’s everything have to be symmetrical??”  It’s rare that you find anything symmetrical in nature, maybe it should apply to this board as well.  

I’ve never used a McKee setup.    However, it seems to me that the closer I’m setting my rears in toward the center the less cant I would want to use.    To be honest, if my rears are only 2" off the center I’d be looking to use maybe only 2* of cant.  Really, you could make the case that setting 2 double foiled fins that close to the center would justify using a vertical/no-toe placement.    I mean, isn’t McKee’s point to make a quad that surfs more like a thruster than a turbo-twin?    

You could very carefully heat up the fin base with a heat gun and push the fin back to your desired angle. 

I have a ton of boards that I run 3/4" Future boxes in the rear so I have access to all of my thruster set front fins. I lessen the can’t when I install the rear boxes on some but I also have a bunch of boards that I didn’t do that so they have the same cant front and rear and they work fine. These of course are flat foiled on the inside and set out on the rail though, I don’t like the Mckee setup too much.

I’d give it go as is since you already glassed and hotcoated, that’s going to be a pain in the ass to cut all that glass off and redo it, I bet it will surf fine.

Great idea sirwanksalot, I’ll give it a shot.

And gdaddy my thinking was McKee+cant=drivey but loose. It’s a wide tailed pointy nose 5’8"x20.5" that was pretty squirrley and lacked drive as a thruster even with a very large set of fins. The side fins are glassed on and I had a center future box so I could change it out depending on the condition. I’m normally a thruster guy with the exception of one twin+trailer. I figured a quad would be something fun and exciting to try 

Thanks for that Johnny, I bet it will surf fine too. I’ll post some pics tonight after I get the fins sanded 

If you ignore all the dust, lumps, and burn-throughs they look pretty sweet. The right rear fin in the photos is the one with too much cant


I would try the heat and adjust technique or take it off now and redo as it will be a more involved process later

Hello; first; design: briefly the rear fins are to hold the front fins are to turn. When you put more tilt on the rear fins you are aiming to turn producing lift but lacking of projection and speed. Depends on your style of Surfing to see how to proceed because if you are a light footed surfed is one thing; if you are in constant movement (changing the AOAs constantly, like a good level shortboarder) is different than if you are just down the line riding.

That method of heating DO NOT WORK; you will tear it up the foam from the foam.

The only way is to cut it from the base with a grinder then sand all over to the lamination sheet with an angular sander then do again the process.

Did the heat gun last night after I posted the pics and it worked great. Both rear fins set at ~2deg. I use epoxy resin over pu foam so I’m not sure if you can do the same with poly resin since it’s more brittle. I took my time heating it then used a weight to keep it propped at the right angle until it cooled. I noticed a air bubble at the base of the outside of the fin but it’s nothing im worried about. It’d be a different story if they were large keels or something that has experiences a lot of force but I don’t think it’ll matter on fins this size. It looks to be where the glass from the fin was over the lam for the bottom of the board. Thanks guys for all the advice. Waves for the next few days (southeast us) so I’m stoked to try it out. My best buddy is out with an injury so he’s been shooting a lot recently. I’ll post an action shot if I get any good ones. 

Cool.  Glad it worked out and hopefully we’ll see some pics.   Lowel

…yes; you did it now you have the foam internally teared it from the foam itself; as mentioned.

 

 

Honestly I don’t see the foam degrading if the fin base was heated up very slowly.  Anyway the fins are anchored to glass and it went well according to op. Have fun with your new board. Thanks for taking the easdy road instead of the hard road and for listening to the advice of someone who has repaired, shaped and glassed boards  in a production factory setting. 

…not foam degrading; the problem is with the hard shell and the soft core so the soft core tear it from the soft foam not from the hard shell. I am not a backyard shaper.

One of the reasons I buy the occasional old blow dryer at Goodwill;  They don’t get as hot as my exspensive heat gun.  Whoever it was that mentioned the differences between Epoxy and Poly when heat is applied was correct.

Wow, how the heck did I miss this trick?  I spend my days B-staging epoxy films for work and have spent the last 20 years obsessing over all things related to board building.  Yet this is the first time I remember hearing of this.  It makes sense that you can do it with freshly cured (read: not 100%-cured) epoxy, but I still would be concerned about the foam.  Perhaps with a delicate touch.  Cool stuff.

BTW, your board looks fun.