The Roberts Twonzer

[GWS]

I always thought of canard placement like the way sails work. The jib smooths the flow over the main sail making it more effective. If you open the slot that effectiveness changes, however as the wind increases, such as board speed, less slot is needed for same effect. But, it still has to be trimmed correctly or the sails will stall or deform (which shows the flow) and you slow down

Interesting. Although a genoa (previously called an overlapping jib) is a foresail that closes the gap between the main the foresail entirely, in fact overlapping. In some cases substantially. And its used in light air.

As a kid I used to crew on boats before roller reefing. I used to hate when they would put one of those things up in light air when I knew it was going to blow in an hour. Because I was the poor slob who had to go up there and drop the beast, wrestle it into a bag and raise the smaller jib sail.

 

[ghostshaper]

+1
agree w/ the sail analogy

Maybe the canard action is only kicking in at this higher speed?

canards are supposed to prevent stall at higher aoa at low speeds

 

[SlicedFeet]

I have 4 boards that are “quads” with added canards, 6fins.

They all perform the same. A 6’10, 7’8, and two 9’0 longboards. I feel the canards increase the speed of the board on roundhouses and bottom turns. Also they are steady as F in the pit, like being on a sidewalk.

For me, I tottaly get the canard. On birds of prey, the reason why they are so agile is that they use their canard to speed up their tight turns when hooking prey. If the canard slowed them down in a turn, they’d be extinct.

I have found that the 6 fin is its own beast, it doesnt work if you just add canards to a traditional quad set up.

Looks like Roberts has put lots of testing on his fin placement too for his Twonzer.

Board look cool.

 

[twinzerfan]

Well said GWS!

I’m sure there’s something to do with the area of the sail too, especially in light airs.

I laughed out loud at your story too

 

[twinzerfan]

[img:left]http://kanatasailingclub.com/wp-content/uploads/2017/05/slot.png[/img]

 

[One-Off]

I've spent a lot of time messing about in boats (not as much as tom@daum who should chime in). The sail doesn't need to overlap to affect the air flow on the main sail. In fact if you look at perfomance boats these days most no not have overlapping jibs.

The air/water cavitates on the outside edge (leeward in sail terms). The canard's inner edge which is working efficiently, even if it itself is cavitating, keeps the outside edge of the main fin from cavitating.

My question is about the depth. Most jibs will reach the mast head or 7/8th or 3/4s of the way up. The canard on boards is less than 50%. Also the main sail on a boat doesn't need the canard at the mast head because you can twist the sail, something you can't do on a surfboard fin.

 

[Spinafex]

I've spent a lot of time messing about in boats (not as much as tom@daum who should chime in). The sail doesn't need to overlap to affect the air flow on the main sail. In fact if you look at perfomance boats these days most no not have overlapping jibs.

The air/water cavitates on the outside edge (leeward in sail terms). The canard's inner edge which is working efficiently, even if it itself is cavitating, keeps the outside edge of the main fin from cavitating.

My question is about the depth. Most jibs will reach the mast head or 7/8th or 3/4s of the way up. The canard on boards is less than 50%. Also the main sail on a boat doesn't need the canard at the mast head because you can twist the sail, something you can't do on a surfboard fin.

Roberts twonser canards look to be about 3/4 of the rear fins. The rears are smaller than regular twins.
Does anyone have ride reports?

 

[Dekerwild]

Picked up a used 5'11 42L Brofish and all I gotta say is I'm super stocked at the amazing amount of speed down the line and it held with all the power I could throw at it. It's a bit oversized for me, i'm 46, 5'10 190LBS, as I wanted a beefy fish style board to just cruise on and nurse my bad knees back into surf shape. The waves were head+ glassy fast down the line runners....this board just accelerated with back foot pressure and I made waves I wouldn't have made on my SB...I'm thinking of upgrading to a disco diamond 5'9 for more high performance shred fest cause the Brofish just reignited my 22yr old brain inside my crusty midlife crisis bones...

 

[Aruka]

Picked up a used 5'11 42L Brofish and all I gotta say is I'm super stocked at the amazing amount of speed down the line and it held with all the power I could throw at it. It's a bit oversized for me, i'm 46, 5'10 190LBS, as I wanted a beefy fish style board to just cruise on and nurse my bad knees back into surf shape. The waves were head+ glassy fast down the line runners....this board just accelerated with back foot pressure and I made waves I wouldn't have made on my SB...I'm thinking of upgrading to a disco diamond 5'9 for more high performance shred fest cause the Brofish just reignited my 22yr old brain inside my crusty midlife crisis bones...

Ancient surf animal brain activated. Hell yeah Barknuckle, get it.