Which fin setup would you think is generally easier to ride for an intermediate surfer who can make the basic turns and hang an occasional fake-five but can’t cut back agressively or cross-step properly:
-HP longboard with a 7’ center and 3,5’ sides or
-the same board with a 4,5’ thruster setup?
if you want to progress as a longboarder, then 2+1 is the only way to go
Give me a longboard with 50/50 rails and a sweet singlefin, everytime. You do not need anything else. Don’t believe me? Take a gander at all the surf movies from the 60’s. Great boards. And only singlefins! Worked for them 
How the board is foiled and rockered will dictate what kind of a fin set-up will work best on it. Flat sided rail fins that have a lot of toe in interfere with trim slowing the board down and make it want to walk from rail to rail. I’ve solved this problem through R&D. With this said your board may be best with any three of the the combinations mentioned above.
The Devil’s in the details.
Good Waves, Rich
CEnter box with side bites.
It would help if we knew the dimensions of the board.
Drew
The board is:
9 foot 17 1/4, 21 1/2, 13 7/8, 2 3/4 thick, round pin tail, lots of rocker, domed deck which results in relatively thin rails that turn hard at about 1,5 foot from the tail. Bottom starts as long single concave and turns to vee.
The reason for my question is that I see more and more thruster longboards around both in videos ridden agressively by pros and at the beach under novice riders.
The beginner boards (NSP, Bic…) seem to be thrusters too.
I don’t know if it’s different situation in California or Down Under, but in Portugal for instance the thruster longboards seem almost as common as boards with big center and sidebites.
(I’d like to skip the single fin discussion here, because it’s so well documented in the other threads unless someone convinces me that a single is the ticket to a vertical learning curve in both sloppy windswell and hollow reefs, and whatever a travelling surfer might meet…)
Hey- Looks like you’ve got a pretty HP longboard. Do a 2+1 setup, that way you have the box in the middle that allows for a wider range of fin choices. if you make the side fins removable also then you can have your cake and eat it too. You can set the board up as a thruster, twin, 2+1, single… whatever you are feeling at the moment. -Carl
Thanks folks. Any more views on thruster setup on longboards like mine? Does anyone of you have a 4,5 in center installed in a box?
To be more specific is three small easier to ride and maneuver compared to a 2 + 1 setup?
Putting a thruster set up on a longboard would take the soul out of the board.
A board witrh no soul is no good to ride.
Center fin box, plus the Stewart side bites. I’d go witha 7: cutaway center fin. This will let you do about anything that a thruster set-up would.
Drew
Hey Biarritz,
Carl’s advice makes a lot of sense.
Some boards work great as a single, some don’t.
IMHO what performs best has the most soul cause you can do more with it.
From the specs and your discription your board doesn’t sound to me like a traditional longboard.
9’0"x 21.5" is pretty gunny so small waves may be a bit of a struggle with it depending on how big you are. If it has a fair amount of tail rocker and pretty hard rails in the tail section it’ll definitely perform better with rail fins. Don’t be afraid to experiment and let us know what ends up working best for you. Just put enough fin power on it so you can work through the soft water and broken sections without side slipping. The board is narrow enough that it will have a lot of it’s on rail drive and should hold a line without a massive center fin. If you put small rail fins on it make the center fin at least 6.5" or 7.0". I wouldn’t use a wide based center fin on the board cause it’ll make it stiff.
You could put larger rail fins on it and down size the center, Say 4.0" rail fins and a 6.0" or 6.5" center and you may be quite happy with it. If you go single you’ll probably want to surf an 8.0" or 8.5" fin well forward in the fin box. Some flex in a single would probably be a good idea. Without seeing the board I can’t make the right call.
Mahalo, Rich
Aloha! From my experience with longboards, I feel that the thruster type is best for narrower, more rocker type boards. The thruster is better for pumping from the tail. This allows the board to work higher up on the face, and has more control in the lip zone. Single or 2+1 lb’s work more off the bottom of the wave. The thruster type seems to be faster, from the fins generating speed. It’s almost always necessary to be continually cutting back, as the design wants to outrun the section. The basic action of the single fin design allows the board to travel at the speed of the wave. This would be more ideal for noseriding and cruising. Putting small side fins on a design like this would actually loosen the board up some, as well as allow for more hold under the lip. Thruster lb’s turn off the tail, whereas any single or 2+1 would want to turn more off the rail, like more up on the board. I think thruster type lb’s can ride like a shortboard, 2+1 types are more tanker like. All this really applies to more modern, down rail type boards. Old style, roll bottom, 50/50 rail type single fins are naturally another story. Aloha…RH
For an intermediate skill level, I would recommend 3" sides and a 7-1/2 center (not too wide base, fast rake). This is what I put on performance LB’s for mostly mushy SoCal waves. Thruster setups work better for faster, more sectioned beach break waves, but I think that your 21-1/2 width is too wide for this (assuming that the tail width is proportionate). I use a 5" thruster setup on 7’ - 8’ funboards and mini LB’s, but these are pretty narrow and are primarily for faster inside waves. Thicker performance LB’s (3"+) sometimes use the Infinity “cluster” setup which is usually 5-6" sides and a 3" or less center. Always keep your options open by using a 10" center box and side boxes on LB shapes.