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Re: TBG5 Step Up

Posted: Wed Dec 23, 2015 6:59 am
by CHRISPI
Thomas I must admit I feel very isolated choosing my board s evolutionary path, none of the surf industry folk lore can be applied or is relevant. But it was this multi fin fade that made me naively reason that if they can drag all thoughts vertical non lifting fins. Why not make them horizontal lifting fins . My boards are not really foil boards but horizontal fin boards . One feature is pan caking is eliminated completely In large choppy conditions. I will admit been part of this forum is Invaluble , its helped me broaden my decision making data ?

Re: TBG5 Step Up

Posted: Wed Dec 23, 2015 7:32 am
by bgreen
vive la difference.

Re: TBG5 Step Up

Posted: Wed Dec 23, 2015 11:56 am
by nomastomas
As SoulGlider, in one of his occasional moments of lucidity, has reminded us, much of conventional "surfboard" wisdom doesn't apply to prone-boards. Someone has to ask the questions that haven't been asked, and someone has to answer, or at least try to answer those questions. I guess you're one of those guys...

Re: TBG5 Step Up

Posted: Wed Dec 23, 2015 3:30 pm
by SJB
OK....here is a naive question for you experts. I say naive because I suspect it has been addressed many times.
Why does it seem to me....that on the 23 liter T4 I experience more chattering "skipping stone" effect than I do on the smaller 21.5 liter T2?
More volume creates more chatter?
More surface area creates more chatter?
Or perhaps....since I have not had the T4 all that long....I have recently been riding waves that would have produced similar chatter had I been on the T2?
Hmmmm.....perhaps more a silly than naive a question
So.....
Has to be a combo of volume, surface area, weight and position of rider, type of wave....with no absolute answer available.
The 26 liter Manta....all things being equal.....even more likely to chatter than a smaller board?

Re: TBG5 Step Up

Posted: Wed Dec 23, 2015 5:56 pm
by bgreen
I'm no expert but you have to also factor in speed and sea surface. The old paipo nui footage has them skipping and it's happened to me on a thicker board, with chunky rails - the opposites of the continuum.

Bob

Re: TBG5 Step Up

Posted: Wed Dec 23, 2015 7:06 pm
by CHRISPI
On my early boards I had split rails , widening into thin staggered top and bottom strakes which also stopped chatter.

Re: TBG5 Step Up

Posted: Wed Dec 23, 2015 7:59 pm
by nomastomas
I have to agree with Bob. "Chatter" is caused by an intermittent loss of contact with the water surface. Given enough speed, any planing hull will lift off the surface. That's what its designed to do. Likewise, surface turbulence (chop) can cause an intermittent lost of contact between the hull and the water surface. Combine speed, the natural lift of a planing hull and turbulent surface water, and you have the skipping-stone phenomenon. Certain bottom contours, like convex/belly, will help to cut through chop. I suspect, displacement hulls are less susceptible to chatter, but not impervious to it.

Both the G2 and the G4 are planing hulls. Given its larger planing surface and greater buoyancy, your G4 lifts quicker than your G2. So, its more likely to produce "chatter" if the surface is choppy. Its also more likely to go faster. I don't get chatter, But I have gotten "bounced" dropping in on larger waves. As in air-drop, bounce , bounce, stick. I'm pushing 200lb with my wet Patagucci R3 and I ride a 23L 48" G4. Even on the 52" 26L Manta, that's still a load. When I sit on the Manta I'm up to my armpits, but on the G4 I'm an inch or so deeper, almost over my shoulders. I'm not too concerned about chatter at this time, but then I haven't been in the right conditions with the Manta yet.

Another advantage of the Manta is that it is more of a displacement hull than a planing hull. In larger surf, I want to minimize lift. I'll have all the speed I can manage from the wave. The issue is more about controlling that speed, hence larger fin surface, and bottom contours that minimize lift. The G4 has more speed "out the gate" in small waves than the Manta, but the Manta feels more solid and smooth-riding. In ski parlance, the G4 is the slalom ski, and the Manta is the downhill ski.

Re: TBG5 Step Up

Posted: Thu Dec 24, 2015 3:18 pm
by CHRISPI
I think soled grip and proper body positioning, side to side, horizontal, back and forward, will control chatter 80 % of the time on any board , a lot of paipo riders miss the horizontal and hunch over their boards , you can pack a lot weight into a small area with an arched back .I see the body on my board as a counter weight run by the most advanced micro processor ever known .I think prone boards need big body movement to work a their best

Re: TBG5 Step Up

Posted: Fri Dec 25, 2015 3:20 pm
by bgreen
Chrispi,

It must be the Christmas food dulling my mind. I didn't understand a couple of your poats:

"On my early boards I had split rails , widening into thin staggered top and bottom strakes which also stopped chatter".

What do you mean by a split rail and strakes on a surfboard? Do you have a photo?

Also, "a lot of paipo riders miss the horizontal and hunch over their boards" - do you mean the opposite of back arch or just not enough? " side to side" - do you mean body is too close or not close enough to a rail line?

Next time it happens I'll see if back arch makes a difference.

Bob

Re: TBG5 Step Up

Posted: Fri Dec 25, 2015 6:10 pm
by Poobah
The split rail sounds like double horizontal. rail fins. Definitely needs its own thread.

Re: TBG5 Step Up

Posted: Sat Dec 26, 2015 12:00 pm
by CHRISPI
Sorry its weed numbing my brain ? its shoulders up hips down to really move around the board.Dose the pic help ?

Re: TBG5 Step Up

Posted: Sat Dec 26, 2015 3:59 pm
by bgreen
Chrispi,

The photo helped as did the clarification (the latter describing a means to ensure back arch).

In terms of the board photo, this seems like an early version of a foil, almost like an iceberg board, with a lot more under the water than above. If you want to make a separate thread feel free, we've strayed a little form the tBG5 subject..

Thanks

Bob

Re: TBG5 Step Up

Posted: Sat Dec 26, 2015 7:05 pm
by CHRISPI
Sorry Thomas. I got lost in the pure joy I get from this subject. Bob its bottom up in the picture ,the bottom chine , strakes or rail is a lot smaller than the top .Water can flow over the lower rail locking it to the wave face damping chatter ,and maybe I am pushing my luck but it also relieves form drag .With lot more lifting surface area in a compact area.

Re: TBG5 Step Up

Posted: Sun Dec 27, 2015 12:31 pm
by nomastomas
The whole concept of two bottom shapes is quite intriguing. Here is one shapers application of Greenough's concept to a fish outline and a Mini-Simmons outline http://thealleyfishfry.blogspot.com/201 ... eorge.html
I haven't yet read an explanation of why or how this configuration works, Greenough says the shape constantly accelerates...

Re: TBG5 Step Up

Posted: Thu Dec 31, 2015 8:58 pm
by nomastomas
I got to put the Manta through its paces in some really clean, chest-high waves yesterday. The board is fast. I dropped into one nice peeler, that suddenly walled up, and I was off to the races. Holding a highline with the lip hissing and foaming, I finally kicked-out (ducked-out, actually) when the wall closed-out in front of me. When I started to paddle back up the point, I realized that I had travelled almost 100yd. Biggest difference I'm noticing is the silky smooth feeling. With the TBG4, I can "feel" the rail and fins gripping the wave face. The ride is "edgy"., as if only the rail and fins are in contact with the wave. The Manta just flows, less drag? Greater speed would reinforce that notion. The Manta has a wider turning radius. It just doesn't dig in and hold like the TBG4 when on rail. But I wanted smooth and predictable for larger waves. Fin-wise, I had 4.6D/4.4B front fins and 4.0D/3.8B rear fins. I'm going to switch to the larger DVS Split-Keel fins for my next go out. Looks like some better swell next week,

I'm more than a little concerned about getting outside when it does get overhead at C St. The side-current there can be brutal, and even with duck-diving, getting under 4' of whitewater can be a challenge. My plan is to start my paddle-out somewhere north of the first pay lot, hoping I can time the lulls and find a little channel. If I'm lucky, I'll only drift as far south as Middles. If I can catch a bomb there, it should take me to the top of the cove, where I can ride the whiterwater in, hopefully avoiding the pier. Depending on how hard the paddle-out, It could be a one-and-done day.

In the meantime Happy New Year everyone....I hope your 2016 is filled with glassy, head-high waves!

Re: TBG5 Step Up

Posted: Fri Jan 01, 2016 10:16 am
by soulglider
happy new year to you too!

Re: TBG5 Step Up

Posted: Fri Jan 01, 2016 4:37 pm
by SJB
And a Happy New Year to you SG and Nomas.
Nomas I concur with your decision to start out North of the Pay Lot on a sizable day at C St. I launched at Stables on such a day last year and almost learned a lesson the hard way. Non stop duck diving coupled with an unforgiving current and by the time I made it past the impact zone I was eye to eye with the end of the Pier. :shock:
Gas tank already half empty...I had to beat my way back North.....one wave took me back South and the white water swept me to the last staircase for dismount. Whew. There is a reason all those life guards hang by the Pier!!!!
Let me know when you are going to attempt that feat of daring and I will come up and watch from shore. :lol:

Re: TBG5 Step Up

Posted: Fri Jan 01, 2016 5:18 pm
by nomastomas
Yeah, SJB, you know exactly what I'm talking about!

Re: TBG5 Step Up

Posted: Sat Jan 02, 2016 1:28 am
by skiff
Nomas, the link you posted from the alleyfishfry blog detailed what are called 'Edge Boards'. Virtually all of Greenough's spoons were edge boards, and Bob Duncan of Wilderness still makes them, and you used to be able to buy 'em off the rack there in Ventura. The edge board design has been around for decades, and is fairly well proven with a dedicated set of acolytes.

Re: TBG5 Step Up

Posted: Sat Jan 02, 2016 12:38 pm
by nomastomas
Thanks, Skiff...I've spent the last few days researching the design and I found a couple photos of Duncan's Wilderness edgeboards. I even found a video of Rastovich surfing Greenough's 6-3. I've seen GG's kneeboard edgeboards and his windsurfing edgeboard, but I haven't found any prone-board versions yet. Do you know if anyone has applied the design to a prone-board?