Just had a surfblanks pink machined today - going to be doing it WMD style with western red cedar skins.
Big kudos to Cameron at Piranha shapes in Narrabeen - he helped me with a few issues on my flow lines, which weren’t easily detected in boardcad
Anyway down to box selection, I was going to use Futures, but last time I used them I had so much slop in the boxes I needed to use thin aluminium to get the fins tight.
I’ve studied the McKee fin formulas, so I’ve also decided to give the Quad option a go. The board has a thinnish foil, but carries area - 15" wide at 12" from the tail,
I’m seriously thinking FCS fusion and will likely go that route as 5 futures boxes will compromise the flex - IMO.
Now I’ve got ~1/2" concave between the front fins, so will need the 9 degree cant plugs for the sides
What’s the general concensus for the cant angle on the rear fins for quads? I know this is a big topic, but please keep in mind I’ll be using the Mckee formulas…
I run the mackee setup with roughly 1/4" toe in on the front at 6-8 degrees cant and the rear with 1/8th" toe in and 4-6 degrees cant.
Seems to do the business.
cheers
Rich www.thirdshade.com
Well the concave was coded as 1/2", though I haven’t measured it since doing the finishing. It does sound deep, but the board only has 2 3/32 tail lift, the concave is ~3/16" at centre, deepens between the fins, actually at 16 1/2", so just in front of the front fins, then disappears out the tail.
It’s a slight modification of a Simon Anderson Thruster I have - that board goes like stink out of a hard turn, either off the bottom or a cutback.
Nothing quite like charging at the lip with speed to burn…
Anyway the fin layout on the Simon board correlates perfectly with the McKee formulas, thus my trust in them.
Thirdshade, which fin/box system have you used?
Reason I ask is since posting I’ve researched the Probox system, looks very functional and gives me the opportunity to make foil my own fins.
I used to work in a pro glassing shop and foiled all of the glass on sets for the next days production. 99% of fins at that stage were glass on…
In fact that would possibly sway me to the probox as well as the fact that I prefer glass ons for their feel, probox looks the best of the bunch in that regard
Has anyone done the probox prior to final lam?
I can do them that way this time as I’m using epoxy and can install them after the skin, prior to lamination for extra strength.
In my humble opinion, probox makes for a very solid feeling fin. Feels closer to glass on than fcs.Great fins too, though it doesnt sound like you’ll have a problem making some!!
I’ll third the Probox system, easy to install with the added bonus of tweaking your angles and positions. You can also use your FCS fins as well.
I bought the complete Quad install kit complete with fins and inserts and everything else you need and it is very good value, they also have their version of various fin set ups as well which are worth taking a look at.
Here’s a pic of my first (and only so far) install that went well, just take your time and it’s easy.
One main reason is the actual ProBox fins that Larry and Robin make are incredible. You look at a mass produced FCS fin vs one of their fins and you can see/feel the difference. They make great fins.
Anyway guys, proboxes ordered and on their way to me shortly.
Whilst negotiating their site I noticed their fin placement templates.
Now I’ve decided my fin placements, using te Mckee formulas, but I noticed some diferences between the McKee formulas and Probox (Robin Mair).
If I wanted to characterise the differences, for a Thruster - Probox suggestions are further forward (13/16" front and rear fins). The cluster is similarly spaced, within 1/16".
The big difference is in the quad fin suggestions, Mckee, closer to the tail on the rear fins, and further from the rail.
Probox the cluster is tighter between fronts and backs, 3/8" inch between front of rear fin and rear of front fin - (suggested) and placed 1" off the Rail.
Anyone with experience of both setups, not trying to incite a “one is better” discussion, just gain some general impressions of performance differences between the two.
If you're a thruster surfer, most seem to like the McKee setup, If you're into rail finned boards ( twinnies etc ) the rail fin setup seems to suit. Just a generalisation though. Im a twin fin fan, and i struggled to find a rythym on a mckee quad i had. I found the quad setups that had rear fins closer to the front fin, and closer to the rail suited me.
