Well, I am now trying to decide on the fin system for my 6'8 performance egg. I'm undecided between a 2+1 setup with a mini box or a thruster, and I wondering what the real difference is performance wise between them. It seem to me that with the same placement of the side fins, they should be identical. The only real difference I can think of is the weight/drag of the fin box. Does the rear fin (with comparable size fin) box make it perform differently than a thruster?
Here’s some feedback from my own experiment with 2+1, on a 7’6 speed egg.
I based the fins on data from a guy who had just picked up his Neil Purchase Sr. 2+1, so felt fairly confident that after some reshaping, the fins were pretty good to go, back fin 6 1/4", fairly vertical, sides 4.25.
Side fin boxes were set at normal for a thruster, as I wanted the option to go back and forth.
so I also picked up a 4.5 True Ames small box fin, which I could match with a set of 4.6" thruster side fins so I could switch between 2+1 and thruster (note, make sure to carry enough tail thickness so you can backset the center fin box close enough to the tail so you can do the same. For a true 2+1, you would ride the front fi couple of inches more forward from where a rear thruster fin would be, so longer box is the key if you want to be able to go back and forth).
So after getting the fins together, started riding the board as a daily driver in varied conditions, swapping fin sets back and forth. Findings:
Found the 2+1 to be really smooth and drivey, ideal for forehand point type surf. Lotta flowing fun.
Found the thruster set-up, however, to be quicker off the top and bottom, better for fast snappy beachbreak, and provided more options on the backhand.
So tended to ride the board much more as a thruster, and when reshaped a year later, it was a thruster only.
Here’s a link to Neil Purchase Jr. website, who along with his dad have been part of the 2+1 vanguard down under, and if you dive into some of the older posts, you’ll find fin template info…
http://nealpurchasedesigns.blogspot.com/
I made a 7-4 set up to run as either 2+1 or thruster. I tried it first as a 2+1 and it was too stiff. I tried it as a thruster and it was too stiff. Then I used the thruster center and the two side bites and it was fast and loose and, no, it wasn’t slippery at all.
I don’t have pics of the set up I’m using but you get the idea.
2+1
Thruster
This is good information thanks dcasey for asking! - I have been wondering the exact same thing.
Found the 2+1 to be really smooth and drivey, ideal for forehand point type surf. Lotta flowing fun.
Found the thruster set-up, however, to be quicker off the top and bottom, better for fast snappy beachbreak, and provided more options on the backhand.
So tended to ride the board much more as a thruster, and when reshaped a year later, it was a thruster only.
I found the same thing on my 7'10'' eggish board. Love the drive of the 2+1, but man, as a thruster the performance went through the roof!, beautiful cutbacks, and backhand was awesome.
Awesome input, and much thanks. I made my 7'6 as a thruster, and I do like the "snappiness" of it. This is why I am hesitant to commit to the 2+1. You know how it is though-can't resist the urge to making some changes on new shapes. I'm going shorter this time for tighter turns in the steep walled beachbreak. I'm wondering it the fact that the board is shorter and wider (6'8) may yield different results from the 7'6ish sizes. My dimensions are 15t x 21.5 x 16.5n x 2.75 thick. Anyone use the 2+1 setups on similar sized boards?
It'll work fine on that size. You know, a 2+1 can be used as a thruster. The 7'10'' i posted was a 2+1, and all i did was put thruster sides in, measure 7 1/2'' back from the rear of the fins, and that's where i put the rear of my thruter sized fin ( old 80's thruster fin that fits in a centre box ). The fin cluster is way forward, but it worked very very well. That way you can use whatever fin setup the surf dictates. I liked an 8'' centre fin for small days, a 2+1 for waist high and fat. Anything bigger, or more hollow, thruster. THough i ended up mainly surfing it as a thruster.
Same idea as lillibel has just shown, although my fins were further forward. It'll work!!
Your setup is what I had in mind. I was thinking of a 5 in. rear fin (which is the smallest I can find for box fin), and then I'll put my normal fcs side fins in. I use a 4.75 fcs trailer now, so I figure this should equate to my normal fin setup. I'll then have the option of switching fins around or riding as a single when it is sloppy and I don't want to break out the LB. Make sense?
Lilibel, that board looks amazing- feel free to post some full pics of it (or direct me to a thread where they are if that’s the case) Sorry to derail the thread a bit- back on topic, I like 2+1s, I like the drive, I like the hold in turns, I like they feel less neutral than thrusters. That said I’ve mostly surfed them as widowmaker type shapes, 6’6" and up. I have a 5’10" 2+1 sitting here that’s meant to be for sale, but is seriously tempting me…
I think I may have found the ultimate comprimise. While surfing today, I looked over my buddy's 6'8 Takayama Scorpion. It has the five fin setup, with the rear as a box fin. Now, i can test it as a quad also. I've never designed a 5 fin board, though, and I am wondering how to place the side fins. As a thruster, I was going to put the side fins 11 3\8 off the tail, with the trailer at 3 5\8. My question is, do I keep this front placement, and set the rear fins a certain amount behind them? Also, do you use the same toe, etc.? There doesn't seem be any beta online, and I didn't bring my tape measure to the beach (damn!). Attached is the fin setup.
Also, I now understand this is called the "quad + 1."
If you notice this board is set up like ProBox Larry talks about in some other posts..(Guy Takayama used his ProBoxes) There is approx spacing between the quads of 1" (side to side and front to back. I like mine about 1 1/4 to 1 1/2). The fins also work in harmony to each other (Meaning they run parallel to each other...not like the Mckee set up) also they are the same spacing off the rail (approx 1 1/8).
The Big box is only there if you want to run a single fin. If you run all five fins...With a huge center fin, you better be dams surf you don't over fin it. That small of a board with five fins will feel like you are dragging a huge chunk of ass.
Asking for exact measurements is difficult, you need to take into condsideration of rocker, rail line and tail width. But if you set it up like a tri fin fronts, then placed your back quads as above the board will work fine. You might even push the fronts up 1/2 to 3/4, So if you were thinking 11" in the fronts, put them at 11 3/4.
So, it sounds like I'll place my fronts in the normal spot as per my thruster, and then I'll space the back quads somewhere between 1-1.5 (side and back) of the fronts. Also, I normally put my thruster fins 1.25 off the rail-is this still cool with a quad?
The reason I want the fin box for the trailer is that I plan on experimenting with all possible fin designs to see which works best. This is a completely new template for me. Who knows, I may like it as a single. In any case, this setup seems to give me the greatest flexibility to experimenting with fin combinations. Once I get it dialed in, I'll duplicate future models with what works best for me.
1 1/4 is ok...remember it all depends on the tail width. The wider the tail to more to sink on a deep turn, the faster the board goes the harder it is to sink the tail. That's why thick wide tailed boards are not the go to style in faster waves. Putting the fins a bit more out board on big butt boards will improve turning on smaller waves. It all depends on what you are using it for.....This is also why guys like the McKee set up too. The McKee set up is good for fast juicy waves, it's closer to a tri Fin set up with the back fins a bit more to the center.
Also if you use the ProBox style set up, make sure you don't over toe the fins on a quad. I personally like about 2-3 inches off the nose of the board, or about 3/16 of an inch. The more rocker the board has, the less toe you need...let the rocker line do the turning, and keep fins from creating too much drag.
1 1/4 is ok...remember it all depends on the tail width. The wider the tail to more to sink on a deep turn, the faster the board goes the harder it is to sink the tail. That's why thick wide tailed boards are not the go to style in faster waves. Putting the fins a bit more out board on big butt boards will improve turning on smaller waves. It all depends on what you are using it for.....This is also why guys like the McKee set up too. The McKee set up is good for fast juicy waves, it's closer to a tri Fin set up with the back fins a bit more to the center.
Also if you use the ProBox style set up, make sure you don't over toe the fins on a quad. I personally like about 2-3 inches off the nose of the board, or about 3/16 of an inch. The more rocker the board has, the less toe you need...let the rocker line do the turning, and keep fins from creating too much drag.
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1 1/4 is ok...remember it all depends on the tail width. The wider the tail to more to sink on a deep turn, the faster the board goes the harder it is to sink the tail. That's why thick wide tailed boards are not the go to style in faster waves. Putting the fins a bit more out board on big butt boards will improve turning on smaller waves. It all depends on what you are using it for.....This is also why guys like the McKee set up too. The McKee set up is good for fast juicy waves, it's closer to a tri Fin set up with the back fins a bit more to the center.
Also if you use the ProBox style set up, make sure you don't over toe the fins on a quad. I personally like about 2-3 inches off the nose of the board, or about 3/16 of an inch. The more rocker the board has, the less toe you need...let the rocker line do the turning, and keep fins from creating too much drag.
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Thanks resinhead. I have a kind of simmons type board, but i went with no toe in. Just doesnt seem to get up and going, and doesnt have the lift/speed it should have. Been thinking of routing out the boxes and adding 1/4'' toe in ( tail is 17 1/8" wide! ). Just made my mind up for me!!.
Thanks for the additional advice on bottom contours, resinhead. After doing much research here, it sounds like concave and vee in the tail is critical for a quad, since this system directs most of the energy to this area. It sounds like the popular contours are concave throughout, or concave to double. I'm thinking of single concave through the entry rocker to flat to double (deep?) through the side fins to flat out the back. Also thinking vee through the side fins to flat out the back, although it seems many of these designs carry the vee out the back. It seems to me that this might drain a little speed from the board.
As far as rails, I'm thinking 60/40 rails that go hard just behind the front edge of the front fins, which is what I use on my thrusters. I find that it allows for sharper turns without creating too much tracking. Also, I'm curious about how the fins are placed closer to the edges on quads. When I've done this on thrusters, I find that it creates tracking. I've always found 1.25 offset (with .25 tow) to work best for me. Is this different because of the additional fins?
Its funny that I've been riding thrusters for 25 years, and shaping them for 8, I am completely in the dark just because I'm adding a couple more fins.
Boards with parallel rail lines, deep fins, flat rockers, and no toe in create tracky stiff boards. Any one of these attributes can create a less than desireable surfboard. But they can all be over come with other design attrubutes. Without seeing the board its next to impossible to say what the proper set up would be. It's like recommending tires for a car without knowing what kind of car? Truck tires for your VW sir!...or maybe Corvette tires for your fire truck?
Here's the rough outline. 16.5n x 21.5 x 15t x 2.75. I created the shape based on the performance egg model I like and what I saw of the Takayama Mini Howard.
Here some ideas for the same shape of a board. This one is 7'11"
