I have a board which supports a thruster setup, and have observed that the board tracks the chop nicely, and accelerates in turns (three straps in).
I liked that a lot, but could not get the board to go fast.

Once reconfigured to 4 straps and a single fin, the board was much faster.
However, some of the nice feel of the thruster setup was lost.

I was hoping for some advice on how to make it go faster in the thruster setup. (Stance, harness lines, etc.).

And the top speed you managed out of the thruster setup?

what are your side fins?
sounds like you could try your usual single fin and add some side bites. gives best of both worlds. single fin feel with a touch more grip.

dunno about top speed as i don't wear a gps but i don't have any issues keeping up with or beating single fin freestyle wave boards

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Gestalt said..
what are your side fins?
sounds like you could try your usual single fin and add some side bites. gives best of both worlds. single fin feel with a touch more grip.

dunno about top speed as i don't wear a gps but i don't have any issues keeping up with or beating single fin freestyle wave boards

12cm side. Thanks, will try that.

Without asking, what board, what fins , side single to say 12cm sides ,conclusion that if anyone agrees , a mass of info is missing

This is a typical issue, that sailors want the advantage of a Tri fin but the speed of a Freeride.

you can't make a racehorse from a pig, but you can make a fast pig ??

You just won't get it as fast in tri fin config as single however i agree with Gesalt and put smaller side fins in, maybe some 9cm will reduce the drag.

Firstly has it got toe-in on the side fins? If it has, nothing will make it as fast as a single. If it has no toe then thin foiled and smaller sidies may get you close

Didn't want to mention the board, as I had it listed for sale.
After having an enjoyable session yesterday, I changed my mind and decided o keep it, so....
Tabou 3S+, 116L. The original centre fin is MFC 25 wave.

It goes fast with a Tribal Speedweed 35cm.
The toe-ins were fitted.

Just had another sail after fitting the side thrusters, as per Gestalt's advice. Used the same Tribal fin paired to a 7m sail, and liked the compromise.
It goes upwind much better, feels more planted in the chop, easy to foot steer.
It may be slightly slower, than the single sin, but not by much. It looks a bit unusual, but will keep the thrusters in.

Still intersted to know if those side boxes are toed in?

Is it still a thing today , that side fins can have different angles ?
I remember building side fin boxes at 3 deg toe in . There were matching fins of 1 degree os so in or out to fine adjust .I specifically remember buying standard or toe in or out side ins.
If that's still a thing you could speed or slow a tri fin.

Yes it is, many boards do have toe designed in. Some quads but mainly thrusters. Like up to 2 or 3 deg.

On most Cobra boards you will find as least a tiny bit of toe.... but that is to account for manufacturing "tolerances" (otherwise known as occasional fk ups lol) so if their jig is off a bit, at least it won't be toe'd OUT.

I am asking if it has any real toe like 2 - 6mm difference between boxes (total) as I'm thinking about thrustering my old one.

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Mark _australia said..
Still intersted to know if those side boxes are toed in?

The "toe-ins" came with the board.

So the fins are toed in and boxes are straight?

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Mark _australia said..
So the fins are toed in and boxes are straight?

Imax, didn't quite understand the thing with "toe-in" degrees.

The toe-ins that come with the board fill the slots well. Hardly a 1mm tolerance on each side
The actual thrusters can be moved 10mm back or forward, but they are pretty much fixed in any other angle.

There are two side bolts under 45 degree angle which fit into the fin horizontal groove, so no fin angle is possible.
The side boxes are parallel to the central fin box.

I don't know what you mean by toe-in but we're talking about the side boxes not being parallel - like surfboards.

Have u measured or do thus appear to be parallel? Even just 2mm in at front edge is significant

Sorry about the confusion. I'm obviously not familiar with the expressions.
My assumption was was that the "toe'in" was a blank insert to fill in the slot.

Just measured it up. 100% parallel with each other, and with the centre board.

Use multifin only for waves or high end control using small sails. Single always with big sails. You want to match sail size with fin size. Big sail big fin, small sail small fin. Fin size is related to board width distribution.

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Obelix said..
I have a board which supports a thruster setup, and have observed that the board tracks the chop nicely, and accelerates in turns (three straps in).
I liked that a lot, but could not get the board to go fast.

Once reconfigured to 4 straps and a single fin, the board was much faster.
However, some of the nice feel of the thruster setup was lost.

I was hoping for some advice on how to make it go faster in the thruster setup. (Stance, harness lines, etc.).

And the top speed you managed out of the thruster setup?

A single fin is faster ... no way of out it. In 16-25 knots high winds I mostly B&J or swell ride, no waves where I sail, and the three fin are almost gone from my boards.

On my RRD 90 FSW at 72 Kg I use a 30 upright (K4 Fang) or a single Maui Ultra Fin X-wave 25. If installing a three fin were easier I would keep a three-fin combo to use when the RRD is really maxed out on 4.7. Range is 4.7-6.5.

On the Starboard I use Maui Ultra Fin X-wave 22 or 24, combined with VERY small K4 Shark 6 cm front fins www.k4fins.com/product/shark-fronts/. I mostly use the 22 + 2x6 and it works very nicely with 3.7-5.4.

Select to expand quote

duzzi said..

Obelix said..
I have a board which supports a thruster setup, and have observed that the board tracks the chop nicely, and accelerates in turns (three straps in).
I liked that a lot, but could not get the board to go fast.

Once reconfigured to 4 straps and a single fin, the board was much faster.
However, some of the nice feel of the thruster setup was lost.

I was hoping for some advice on how to make it go faster in the thruster setup. (Stance, harness lines, etc.).

And the top speed you managed out of the thruster setup?

A single fin is faster ... no way of out it. In 16-25 knots high winds I mostly B&J or swell ride, no waves where I sail, and the three fin are almost gone from my boards.

On my RRD 90 FSW at 72 Kg I use a 30 upright (K4 Fang) or a single Maui Ultra Fin X-wave 25. If installing a three fin were easier I would keep a three-fin combo to use when the RRD is really maxed out on 4.7. Range is 4.7-6.5.

On the Starboard I use Maui Ultra Fin X-wave 22 or 24, combined with VERY small K4 Shark 6 cm front fins www.k4fins.com/product/shark-fronts/. I mostly use the 22 + 2x6 and it works very nicely with 3.7-5.4.

that's why i use futures boxes. there are so many more options for side fins.

the K4 are the only sidebites i know that fit slot box. any bigger than 6cm isn't really a side bite.
with futures boxes i can go right down to 4cm or even use bonzer or nubster fins.

I'm learning all new vocabulary here

After comparing the setup in similar wind/chop conditions in two days, the speed difference was about 3 knots.
(the same sail/center fin).
The difference from the original wave main fin (albeit, with the straps in) would be another 3-4 knots down, so it's a compromise I was looking for.
The next option I can try is Mark's advice to fit a shorter and thinner side fins.

Small sides, slippery main, powered up, mast track forwards.
Powered up most important.

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Gestalt said..

duzzi said..

Obelix said..
I have a board which supports a thruster setup, and have observed that the board tracks the chop nicely, and accelerates in turns (three straps in).
I liked that a lot, but could not get the board to go fast.

Once reconfigured to 4 straps and a single fin, the board was much faster.
However, some of the nice feel of the thruster setup was lost.

I was hoping for some advice on how to make it go faster in the thruster setup. (Stance, harness lines, etc.).

And the top speed you managed out of the thruster setup?

A single fin is faster ... no way of out it. In 16-25 knots high winds I mostly B&J or swell ride, no waves where I sail, and the three fin are almost gone from my boards.

On my RRD 90 FSW at 72 Kg I use a 30 upright (K4 Fang) or a single Maui Ultra Fin X-wave 25. If installing a three fin were easier I would keep a three-fin combo to use when the RRD is really maxed out on 4.7. Range is 4.7-6.5.

On the Starboard I use Maui Ultra Fin X-wave 22 or 24, combined with VERY small K4 Shark 6 cm front fins www.k4fins.com/product/shark-fronts/. I mostly use the 22 + 2x6 and it works very nicely with 3.7-5.4.

that's why i use futures boxes. there are so many more options for front fins.

the K4 are the only sidebites i know that fit slot box. any bigger than 6cm isn't really a side bite.
with futures boxes i can go right down to 4cm or even use bonzer or nubster fins.

I will bite, a 7cm fin is called what then?
Black Project have slot box, Makani, what am I missing ?

K4 had a chart with toe in , can't find it.
Simmer had the greatest amount, about 1.5
About .75 was an average.
if it came to 2.0 or so, it would be advantageous to use asymmetrical fins.

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forceten said..

Gestalt said..

duzzi said..

Obelix said..
I have a board which supports a thruster setup, and have observed that the board tracks the chop nicely, and accelerates in turns (three straps in).
I liked that a lot, but could not get the board to go fast.

Once reconfigured to 4 straps and a single fin, the board was much faster.
However, some of the nice feel of the thruster setup was lost.

I was hoping for some advice on how to make it go faster in the thruster setup. (Stance, harness lines, etc.).

And the top speed you managed out of the thruster setup?

A single fin is faster ... no way of out it. In 16-25 knots high winds I mostly B&J or swell ride, no waves where I sail, and the three fin are almost gone from my boards.

On my RRD 90 FSW at 72 Kg I use a 30 upright (K4 Fang) or a single Maui Ultra Fin X-wave 25. If installing a three fin were easier I would keep a three-fin combo to use when the RRD is really maxed out on 4.7. Range is 4.7-6.5.

On the Starboard I use Maui Ultra Fin X-wave 22 or 24, combined with VERY small K4 Shark 6 cm front fins www.k4fins.com/product/shark-fronts/. I mostly use the 22 + 2x6 and it works very nicely with 3.7-5.4.

that's why i use futures boxes. there are so many more options for front fins.

the K4 are the only sidebites i know that fit slot box. any bigger than 6cm isn't really a side bite.
with futures boxes i can go right down to 4cm or even use bonzer or nubster fins.

I will bite, a 7cm fin is called what then?
Black Project have slot box, Makani, what am I missing ?

7cm and bigger fins are typically used with a tri fin or thruster setup.... ie. bigger side fins with small centre fin

A side bite is different, it's a small side fin specifically used with a large centre fin to add more grip or drive in the surf. referred to as a 2+1 setup or a widow maker. this is the setup i primarily use for bump and jump in powered up conditions and on my big volume wave sups.

one of the guys i sail with locally is retro fitting bonzer side fins to his boards.

Call the fin what you like.

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forceten said..
Call the fin what you like.

then no-one will understand what it is you mean because we are talking multi fin setups.

Select to expand quote

Gestalt said..

forceten said..

Gestalt said..

duzzi said..

Obelix said..
I have a board which supports a thruster setup, and have observed that the board tracks the chop nicely, and accelerates in turns (three straps in).
I liked that a lot, but could not get the board to go fast.

Once reconfigured to 4 straps and a single fin, the board was much faster.
However, some of the nice feel of the thruster setup was lost.

I was hoping for some advice on how to make it go faster in the thruster setup. (Stance, harness lines, etc.).

And the top speed you managed out of the thruster setup?

A single fin is faster ... no way of out it. In 16-25 knots high winds I mostly B&J or swell ride, no waves where I sail, and the three fin are almost gone from my boards.

On my RRD 90 FSW at 72 Kg I use a 30 upright (K4 Fang) or a single Maui Ultra Fin X-wave 25. If installing a three fin were easier I would keep a three-fin combo to use when the RRD is really maxed out on 4.7. Range is 4.7-6.5.

On the Starboard I use Maui Ultra Fin X-wave 22 or 24, combined with VERY small K4 Shark 6 cm front fins www.k4fins.com/product/shark-fronts/. I mostly use the 22 + 2x6 and it works very nicely with 3.7-5.4.

that's why i use futures boxes. there are so many more options for front fins.

the K4 are the only sidebites i know that fit slot box. any bigger than 6cm isn't really a side bite.
with futures boxes i can go right down to 4cm or even use bonzer or nubster fins.

I will bite, a 7cm fin is called what then?
Black Project have slot box, Makani, what am I missing ?

7cm and bigger fins are typically used with a tri fin or thruster setup.... ie. bigger side fins with small centre fin

A side bite is different, it's a small side fin specifically used with a large centre fin to add more grip or drive in the surf. referred to as a 2+1 setup or a widow maker. this is the setup i primarily use for bump and jump in powered up conditions and on my big volume wave sups.

one of the guys i sail with locally is retro fitting bonzer side fins to his boards.

Good to know that I am using "side bites"! The effect of the tiny 6cm is indeed a bit more lateral grip and a slightly more planted board ... which seems to help calm things down in 3.7/4.2. The Starboard is a Kode FSW 81 L.

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Gestalt said..

forceten said..
Call the fin what you like.

then no-one will understand what it is you mean because we are talking multi fin setups.

The question of what to call fins in a multi fin configuration, never quite made it from a surf board into accepted terms.
you are trying to make a category based on size. thrusters is what many call side fins.

not knowing if your board has toe in, leads me to believe that call them what you want, cause these un informed it matters none.

Are these slotbox side bites common with the kiteboards and surfboards, or are they specific to windsurfers?

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Obelix said..
Are these slotbox side bites common with the kiteboards and surfboards, or are they specific to windsurfers?

Since I only have windsurf, I don't know.

I seem to have gotten along fine with multi fins.

F10
Surftalk time
Thruster was 3 fins.
Twinny was 2 fins.
Single was 1 fin.
Quad was 4 fins
Pentafin was 5 fins
Multi fin is a very broad term. Could be anything from Twinnys Thrusters Quads Pents n beyond.
PS ive got a Multifin from the late 80s.
Its actually a SINGLE fin.