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The Misfit

Posted: Sun Sep 02, 2018 1:04 pm
by nomastomas
This one is a 'tweener, falling somewhere between a proneboard and a kneeboard. Dimensions are 5'6" x 23" x 2" 38L. The fin array is set for a knee rider, which is how I intend to use it. Kneelo guys like to have the fins located where their ankles fall (or vice versa) At least that what I've been told by experienced Kneelo guys. The standard is 16" up from the tail for side fins (quad rears 8" up). Center fin varies depending upon whether its a thruster setup or a 2+1 setup. But in designing this shape, it occurred to me that a prone rider would want the bump in the outline and the fin location to coincide with the location of the rider's hips. I think the current fin placement might just be in this location. I won't know until I ride it prone.
On a side note, this stringerless blank had a great deal of flex prior to glassing. More so than any of my stringerless proneboards. In fact, I had my glasser add the carbon fiber strip for a little insurance. The CF eliminated the flex almost entirely. And with two layers plus a knee patch of 4oz S-cloth on the deck, and two layers on the bottom, the flex is now almost undetectable. I added a kneepad after these photos were taken.

Re: The Misfit

Posted: Sun Sep 02, 2018 2:14 pm
by krusher74
Its great to see your designs, your one of the few people i see trying things that don't look like everybody elses. 8-)

Re: The Misfit

Posted: Sun Sep 02, 2018 2:25 pm
by nomastomas
Thanks Keith...I try to focus on what works best. Form follows function
Prone riders are not as hung up on the “current fashion”. Maybe kneelo guys are the same.

Re: The Misfit

Posted: Sun Sep 02, 2018 3:03 pm
by kage
Nice looking board. Look forward to seeing it with fins and pad.

Re: The Misfit

Posted: Sun Sep 02, 2018 8:56 pm
by nomastomas
Pad on deck, fins on bottom...

Re: The Misfit

Posted: Mon Sep 03, 2018 5:02 am
by krusher74
Now We can see the bottom with the fins there is a lot going on on that hull!!

talk us through that central from planing section and the big double concave, what are you hoping to get from them?

Re: The Misfit

Posted: Mon Sep 03, 2018 5:09 am
by zensuni
I am not competent to talk about the technical choices but I do love the "angular" look of this board

Re: The Misfit

Posted: Mon Sep 03, 2018 11:13 am
by nomastomas
The TBG5 is what I call a modern planing hull, which is designed to ride above the water rather than through it, i.e. displacement hull. This shape is essentially the TBG5 stretched out to 5'6" and widened to 23". Rocker has been increased at both ends. This is necessary whenever you lengthen a shape in order to duplicate the rocker curve (conversely, rocker is reduced at both ends when shortening the length). Starting at the nose, there is belly or rolled bottom in the first 12 inches or so. This serves to cut through chop and to be more forgiving on the drop in. It also increases the rocker out at the rail, so as the board is put on rail to turn, there is still ample nose rocker. The belly transitions briefly (as in an inch or two) to flat and then to a shallow concave (roughly where the CF strip is located). This concave, which is deeper in the middle than at either end or either side, creates lift as water flows across it (keep in mind that, unlike the linear flow of water from nose to tail when paddling, water takes a diagonal, slightly curvilinear flow across the bottom when on the wave.) The single concave feeds into the double exit concaves, which are deeper and wider at the tailblock then just in front of the fin array where they start. The idea is to provide a progressively less restrictive path for water to flow. Lindsay Lord discovered that there is a pressure build-up beneath the rear 1/3 of a planing hull when that hull is at planing speed. This pressure creates drag. The exit concaves, by enhancing water flow, serve to reduce this drag. The TBG2 had a single exit concave, but it occurred to me that typically, unless turning, a prone board has only one side of the tail fully engaged in the wave at a time. So I split the exit concaves into two. (The similarity of this aspect of the bottom contour to the work of the Campbell Bros is undeniable. However, with a CB Bonzer, the flow management of the concaves is enhanced by the fin array.) Additionally, there is "V" in the last 1/3 of the bottom, with the greatest amount of V at the tailblock. This V helps such a wide shape roll onto it rail easier for quicker turning. Finally, there is a concave bevel on the bottom of the rail that extends through the middle of the board. This bevel helps to create a relatively thin rail profile that enhances hold in the wave face, complimenting the hold created by the fins at the rear. (while from a distance appearing similar to Greenough's edge bottoms, close inspection reveals the lack of a hard edge and the steep, vertical transition found on those. And, there is no design intent to reduce wetted surface.)

I have a customer who has been riding this very same shape, albeit much thicker and longer, for a couple of years. He has been happy enough with the performance to order a second and a third, with a fourth on the books. His progression has been to go shorter with less thickness with each iteration. So, I have a great deal of confidence that this 5-6 board will perform. I'm just not that confident in the rider....

Re: The Misfit

Posted: Mon Sep 03, 2018 4:58 pm
by belly rider
Hey Thomas I am very confident on the "rider"-- just give us your opinion and feed back especially on the forward fin positioning of this Hybrid board when you ride it on your knees-- This is a cross between a Mega Paipo and a Kneeboard great idea. Replacing the stringer with that carbon fiber strip seems to me a great way to save weight (verses a traditional wooden stringer) as well as a proper way to stiffen up the board. Especially if placed right under the rider when knee riding. Man I sure would like that idea integrated on my next board.