Hey I have a restoration and twinzer-conversion project goin that I’m excited about: decrepit 1993 Jim Phillips 7’11 midsize which was a glass-on thruster until I ground them off and sanded the area flush (thrusters are lame), since I wanna put in a twinzer set up with FCS x2 plugs for ease of post-lam install. I did post lam installs of future and FCS quad rears on all the boards I regularly ride if they didnt have the quad option, since I love not having a center fin, and I’ve used the Mckee formula which has worked really well each time, but haven’t found any such placement formula for the twinzer set up or helpful information for twinzer placement on midlengths specifically.
The boards’ 7’11 x 21" x 16" (tail) x 14.5" (nose) x 3"; it’s gotta moderate vee bottom from about 1’ in front of where the side fins were and runs through the tail, slight belly through the middle and a slight single concave nose. Also the entire area around where the center was was extremely delaminated and rotting, so I routed it out.
So could y’all help me out with all the numbers for the distance from tail to trailing edges of both the main fins and canards, distances to rail, overlap, etc.?
Rockers’ staged, just some moderate tail rocker, less in the middle and some kick in the nose. I’m a regularly footer surfing mostly right hand points (steamer lane), and am a chicken legs build at 6’0 and 125lbs so my stance is wide relative to my weight. I like riding boards like this (aka my short thin and highly rockered performance longboards such as 8’0 T&C mini tank model, 8’6 Pearson Arrow Josh Muir model) basically as shortboards that allow me to noseride as well as release the fins when I’m on the nose (helicopter). So I intend on using it to let me do critical rail surfing when the waves are weaker and/or softer, and I like a quick rail to rail transition for this.
The reason I asked is because boards that are set up for thrusters tend to have more rocker than boards that were set up for twins or twinzers. With a thruster you gots to plant your rear foot over the center and work the cluster, whereas twins and twinzers will do most of the work on their own. That “fighting the rear fin” thing you’ve got going is most likely the result of not getting your rear foot over that center fin; you’re basically fighting the fin cluster instead of using it as designed.
Also, an 8ft board is a lot of board to be turning off a high aspect twin fin, and your stature/stance aren’t ideal for that. Plus, that’s a 16" tail, not a 14.5" tail, so 16" is a lot of real estate to control. I like twinzers, but this is one time I’m going to suggest going back to a quad with dual foiled rears that are inset from the rail (like a McKee or Rusty quad). I would also suggest mounting the cluster further up, where your rear foot will be at the rears in the fin cluster.
Fill the hole in the bottom of the board with foam and reshape/glass; don’t try to use filler to fill all that.
Ah I’ve heard about that relationship between tail rocker and fin setup and placement, especially how high tail rocker functions (at least sometimes) to keep the center fin from sitting too deep in the wave, which creates the bad “anchoring”. My 6’9 x 18 x 2 1/8 high rocker thruster (particularly high rocker in tail) step-up works good in big and especially really steep situations so long as my foots all the way back on the tail pad, but drags on slopier waves yet I still gotta have my rear foot that far back to. But post quad rear installation, is better in basically every way: more drive, more hold, better release and pivot, can handle bigger waves than as a thruster and surfs smaller waves better too. In general I tend to keep my back foot all the way back even when I should scoot up momentarily for this or that reason. Likewise my very low tail rocker quad 5’9 has its cluster skewed a tad forward, and when I put a center fcs plug for a nubster it was awful: slower, no benefit of more hold or stability, horrible anchoring during turns. Definitely a learning experience!
What’d ya mean by a “high aspect twin fin”? And come to think of it, Bob Pearson’s twin fin performance longboards, and Vince Broglio’s and Joey Thomas’s signature twinzers don’t have wide tails, yet twin and twinzer fish often do, so what gives? Why wouldn’t a wide tailed board like my 7’11 POS restoration project work as a twin or twinzer?
I got sacrificial boards I harvest foam from for that purpose. Also at the risk of vanity, here’s how I stand, maybe its not all that wide I guess its subjective, i’m on a 5’6 for reference
It’s your board. You can do a twinzer if you want. The reason I was talking about high aspect fins is because that is a 7-11 length so there is a lot of volume and inertia going on, way more than with a fish or a shortboard. And Future boxes are known to twist/roll when subjected to heavy side loads.
You may recall that I asked how you intend to surf the board, because it won’t surf like a shortboard or a fish. If you’re planning on using it in micro conditions when you can’t surf a smaller board that calls for something different than if you’re trying to use this in a wider set of conditions. At slow speeds you’ll actually get less drag and resistance in a turn with a singlefin, set forward a bit under your rear foot. You don’t actually WANT to outrun the wave. You’ll be letting the long rail line act as your engine, not the fins. But for faster conditions you’ll want that energy out at the rail, and the leader fin to provide the additional hold.
Anyways, if you really want to do the twinzer then you can set the trailing edge at about 9-10 inches. Run the mains fairly upright at 2* or 4* and run the canard at 8*-10*.
So if high aspect mains twist and roll under load especially in future boxes for this board with a twinzer set up, what would compromise exactly? Just curious even though I plan on using FCS x2 plugs regardless of which setup I end up installing.
I plan on riding it in playful 4-6 or 7-8 foot if soft waves but totally contingent on how it actually rides but definitely not micro pathetic surf. Sorry I didn’t completely clarify, on my little performance longboards I dont totally ride em as shortboards, just do certain critical shortboard-like maneauvers utilizing a super tight turning radius while taking a more longboardy line generally. That bonzer runner + taller fin setup is interesting. How do those bonzer runners compare to conventional upright canards?
As far as I can tell, “convertible” surfboards almost always end up being used in just one configuration. Due to the rocker, I think that board would be most versatile as a 2+1 with the trailing edge of the main fin @ 6" or more. That would put the center of effort more forward than where it was as a thruster and would make it easier for most surfers to surf.
If you want to do it as a twin then you can set those at 9"-10". You can reinforce a Future install for use with twins or keels by adding a high density PU foam insert, shape and glass and then install the Future box post lam. Most fin system failures occur due to the surrounding foam flexing more than the box or plug, so using a denser foam will have less flex right there and better support the box.
So true, the unused fin configuration in multi option boards is basically an insurance policy.
Ah that makes sense, especially in a board like mine that’s already ancient.
If you dont mind another question, for twinzers in general what feature(s) are most determinative of the distances from the trailing edges to the rail ?
Trailing edge of the main fin @ ~1" to 1.1/2" off the rail, set back as far as your rear foot goes when you surf.
The primary reason people have trouble turning the longer boards is because when they pop up they are standing too far forward. They don’t have enough leverage over the fin cluster. That’s most likely why you are struggling with a thruster cluster; you’re not getting your rear foot back far enough. Even on that 5-6 that you posted, the board would turn better if your rear foot was all the way back against the backstop. When you pump a thruster you always gotta pump it like you mean it. Heavy rear foot. Don’t skip leg day at the gym.
I know how to make a thruster work with me and not against me, I just think quads are so much more rewarding once you find one with proper placement and then dial in the combo of front and rear fins vis-á-vis symmetrical or 80/20 or flat foiled rears, flex, depth, and so on and so on. My theory for thrusters shortboards in general (im curious on your thoughts on this) is that in order to have the all the benefits of a thruster–– stability, engagement, pivot, etc. ––but without the typical association problems–– drive loss when trimming, “anchoring”, etc. ––the other features of the board must compensate for the defects of thrusters to give it the magic factor, whether its rocker, bottom contours, rails, etc. or a combination of multiple or all. I had this squash tail m10 thruster that was absolutely a magic board which had all the pros but none of the cons of thrusters. I think this also applies to the Pyzel Phantom model, and this custom very low entry rocker 5’9 Arrow thruster i rode in my last 2 years of high school. I’ve heard the same thing about the performace thruster shortboards Ward Coffey makes for his QS-competing sons, that they’re so easy to ride. So im not anti thruster always and in all ways, I simply prefer my boards being way further toward the slippery end of the spectrum as opposed to engaged.
My toes were definitely pushing against the block of the tail pad in that pic (I remember that wave, in that moment I thought i might make the Table Rock section by taking a lower line to avoid the lip, but ended up being way too deep). And I put tail pads on all my performance longboards, people think Im weird for doing so but I like to know when my backfoot is or isn’t all the way back there, and it lives on the tail pad. Here’s a compelling idea: I could put a tail pad on the 7’11 in order to determine where my back foot will be, which in turn would inform fin placement
Like I said before MOST surfers - myself included - will do better on a quad than a thruster. When the board is designed for the quad. I like twins and twinzers, too, but not as much for the bigger boards. Not enough leverage.
Among others, Joe Blair makes a lot of the bigger boards (albeit aimed at the big guys) and he has some interesting fin placement. He favors quads quite a bit and he mounts them further forward than most, with good results. He has some good explanations on his website.
Damn the dims he lists are XXXXL, and for a few of the quads I noticed that he mentions moving the fins way up… So the wisdom is that moving the pivot point forward suits his ultra thick and wide midlengths/ oversized easy shortboards? I suppose that’d make sense if narrower boards in general tip from one rail to the other more easily than wide ones.
