curved vs. straight bottom channels

Should bottom channels curve open with the rocker or cut straight with the fins?  I’m guessin that black widow / hour glass curved channels feel looser than straight cuts and offer more flow and release deep in the pocket. / Straight channels offer more grip, control, and drive while stalling through hard turns.

I like channel bottom tails in powerful surf because there is less flex and the lower volume tail sinks into the power pocket with less resistance.  

Also please post your g-string / bikini bottoms.  “I am a therapist. Not a rapist.  So stop screaming for help.”




curved ( on left ) did not have the same drive as the straight ( on right ) . curved felt more like a normal concave bottom

Knowaloha thanks for the pics.  Looks like the curved channels on that board would choke the flow of water.

Has anyone rode channels that curve away from the stringer as they exit the tail?

 Thats pretty much a bonzer style concave.



never rode one BUT Greg Griffin will let me know when he finds a glaminator that will do them :slight_smile:

There’s a lot of opinions on channels.   Mine is that the longer they are, the less they become integrated with the fin setup and therefore become more of a bottom-contour feature.   I see rear channels as fin enhancements, and that’s why most successful channel bottoms have glass-on’s so it’s fixed.   Straight and short channels if done right provide more drive, but often the same effect can be obtained just using a different fin setup…  And unless it’s clean 4-5’ , you can’t see any difference with or without channels (for the same fin setup), but that’s just my observation.

I’ve done, and ridden, all kinds of channels over the years, and in my experience, the angle of the channel needs to work with the fins and bottom contours. These are some pretty gross generalizations, but… I use shorter, more angular channels with concaved bottoms, and longer, straighter channels in with vee or rolled vee bottoms. I like to lay out my fin toe in angles first, and lay out the channels based on that. It’s a natural match for me because I like less toe in with vee bottoms on big wave boards where control is needed and fins are straigher, and more toe in with concaves on small wave boards that work better with more toe. I never pull the channels together in the tail… they’re always fanned out from front to back. The channels themselves can be layed out straight (linear) or curved, and always curve away from the stringer. If curved, the curve is very gentle. Too much curve creates too much drag. But a slight curve (my theory here) might provide some extra lift (drive) when the board is on a rail, depending on the shape of the wedge.

I always add a little extra rocker in the tail with channels, and I like them deepest through the fins and fade them out before they run off the tailblock. If I’m doing glassons, I like to set the inside edge of the fin right along the edge of the channel, and use a smaller fin. Boxes go between the channels, and you have to play close attention to cant angle. I prefer wedge shaped channels over curved grooves or vee shaped.

I can only speak from very limited experience.  I’ve had two “standard” 6 channel thrusters and liked them, but nothing magic.  Then I made this twinzer.  I asked a few times on this board and the surfermag design board about what difference straight channels and curved channels make and got no answers.  I was going to go with straight channels because the just seemed easier to shape, but once I drew them on the blank they just looked wrong.  Too far from the fins.  A straight line in a sea of curves.

I drew the curved channels (inspired by Russ Hoyte) and they looked right, although I kept thinking, “It’s like reverse toe in. What’s that going to do?”  Sometimes I do things based purely on aesthetics with no logical reasoning behind them. But Formula one cars look fast and go fast. TP52 sailboats look fast and go fast.  I know it’s a pretty weak argument.

So, I don’t know what is doing what but this board is quick, fast and loose.

I liked how the e wings and channels seemed to rise in unison, like kicking the rocker…


the most recent batch of Jobson twinzers have an interesting channel layout




Thank you for the beautiful images.  Setting the angle and toe of the fins in sinc with the angle and toe of the channels feels like a great idea.

Is there a general preferance to placing the fins on the edge of the channels vs. the center of the step?  

I dream of making custom glass on fins that fit the the board and rider like a zen garden…


Griffin and Oakfoils get me excited.

Channels that step up and down?




And Jo

[img_assist|nid=1068918|title=channel 2|desc=|link=none|align=left|width=640|height=499]


Mirandon twin pin influence?


Is that a shortboard with nose bevels in the foreground?  Mmmmmm…



                         That shape and outlne looks unreal ! Have  a great campout .



yep the Jobson has nose bevels , they go from the nose and then fade to a normal tucked edge right infront of the fin area .