TBG5

What works and what doesn't. Share design ideas, references and contacts for paipo board builders.
User avatar
nomastomas
Big Wave Charger
Posts: 515
Joined: Thu Nov 17, 2011 2:30 am
City: Ojai
State or Province: CA
Country: USA
Interests: Surfing, cycling and fishing
Location: Ojai, CA
Contact:

TBG5

Unread post by nomastomas » Tue Aug 08, 2017 2:14 pm

After months of designing and re-designing, I've come up with the latest iteration of the T-Belly. This one is heavily influenced by a kneeboard I built for BellyRider, which in turn was influenced by a progressive SUP design I did for the guys at Melody Surfboards in Greece, and 7-8 Mid-size shape that I’m now riding. All the above would fall into the "modern planing hull" school of surfcraft design. Nothing that hasn't been done before, just my interpretation, in this case applied to a prone board. The dimensions of this G5 are 49" x 22-1/2” x 2”-2-3/8” 23.5L.
The most obvious (and only) change in the outline is the diamond nose. I normally ride a 48" G4, but for a variety of reasons, I found myself on a 49" G4 for the past several months. I enjoyed the added length of the 49"er but didn't like the stretched reach to the nose when in the paddling position. The diamond shape reduces the reach by a good 1-1/2” at the corners, so we’ll see.
TBG5_web.JPG
TBG5_web.JPG (19.74 KiB) Viewed 5213 times
The bottom has the more obvious changes. Adding a bevel to the rail has a similar effect of adding “V”, namely it changes the rocker curve out at the rail, and assists in getting a relatively wide board over on rail for turning. As I looked at the beveled rail in cross-section, it occurred to me that I might be able to make the rail shape more effective by making that bottom rail-band concave. Looking at the concave bottom rail-band in cross section I could see (in my mind’s eye) not only a better hold into the wave face, but also a means of channeling water flow towards the tail. This concave would also reduce the volume of the rail, producing a thinner rail for better wave-face penetration. (A more effective rail profile may lead to a reduction in the fin area needed to obtain the same hold properties as the G4).
TBG5_Bot01_Web.JPG
TBG5_Bot01_Web.JPG (35.03 KiB) Viewed 5213 times
TBG5_Bot03_web.JPG
TBG5_Bot03_web.JPG (61.3 KiB) Viewed 5213 times

The bottom is otherwise standard G4; convex nose, slight concave in mid-section and dual exhaust tail concaves. I’m starting to thin out the tail of my prone boards a little more. I believe this helps the tail sink on take-off, keeping the board (and rider) more parallel. The board will have quad fin-boxes (of, course) and I designed a small, relatively flat section in the bottom where the fins will be located as a courtesy to my glasser. The board will be finished in 5.7oz carbon fiber, one layer deck and bottom. At this point in the process shaper becomes surfer, and I begin to pester my glasser with “Is my board ready yet?”
Attachments
TBG5_Slices.jpg
TBG5_Rail01_web.JPG
TBG5_Rail01_web.JPG (52.11 KiB) Viewed 5213 times
Last edited by nomastomas on Wed Aug 09, 2017 1:30 am, edited 1 time in total.
"This is a paipo site...isn't it?"
www.tp4surf.com

Pes78
Big Wave Charger
Posts: 262
Joined: Wed Jan 07, 2015 1:39 am
City: San Diego
State or Province: CALIFORNIA
Country: United States

Re: TBG5

Unread post by Pes78 » Wed Aug 09, 2017 12:25 am

That looks like a good time. What blank did you use?

User avatar
nomastomas
Big Wave Charger
Posts: 515
Joined: Thu Nov 17, 2011 2:30 am
City: Ojai
State or Province: CA
Country: USA
Interests: Surfing, cycling and fishing
Location: Ojai, CA
Contact:

Re: TBG5

Unread post by nomastomas » Wed Aug 09, 2017 1:28 am

Its 2lb eps from Marko, probably slab cut. Because its stringerless, its just easier to send the file, approximate dimensions and my density requirement, and they do the rest. That way I'm not paying for foam I don't need.
"This is a paipo site...isn't it?"
www.tp4surf.com

User avatar
bgreen
Big Wave Charger
Posts: 1051
Joined: Fri Aug 19, 2011 5:17 pm
City: Brisbane
State or Province: Qld
Country: Oz
Contact:

Re: TBG5

Unread post by bgreen » Wed Aug 09, 2017 4:20 am

Nomas,

When it's glassed I'd be interested to see a shot from the tail looking down.

How wide is the planning area before the concave - 18"?

User avatar
nomastomas
Big Wave Charger
Posts: 515
Joined: Thu Nov 17, 2011 2:30 am
City: Ojai
State or Province: CA
Country: USA
Interests: Surfing, cycling and fishing
Location: Ojai, CA
Contact:

Re: TBG5

Unread post by nomastomas » Wed Aug 09, 2017 11:02 am

I presume you mean the single concave that runs down the center. It's 14" wide at the center. The nose belly starts to go concave at 3'4.74" up from the tail. The single starts to go double at the mid-point. All the transitions are very subtle and can be seen best with the CAD software. I forgot to mention that some of the inspiration for the bottom came from George Greenough's "Edge Boards".
"This is a paipo site...isn't it?"
www.tp4surf.com

User avatar
bgreen
Big Wave Charger
Posts: 1051
Joined: Fri Aug 19, 2011 5:17 pm
City: Brisbane
State or Province: Qld
Country: Oz
Contact:

Re: TBG5

Unread post by bgreen » Wed Aug 09, 2017 5:03 pm

Thanks. It was the concave I was referring to.

The raised bottom did remind me of an edge board. Flatter where the single concave is and without the double concave/vee is one of many ideas I had been toying with.

User avatar
nomastomas
Big Wave Charger
Posts: 515
Joined: Thu Nov 17, 2011 2:30 am
City: Ojai
State or Province: CA
Country: USA
Interests: Surfing, cycling and fishing
Location: Ojai, CA
Contact:

Re: TBG5

Unread post by nomastomas » Fri Sep 08, 2017 6:08 pm

So...after what seemed like an inordinate amount of waiting (speaking here as a surfer not a shaper ;) ), I picked up the G5 at my glasser's. All I can say is "well worth the wait". I opted for the red accent because the bottom contours, when sheathed in carbon fiber, reminded me of an F1 race car, and the red added to that aesthetic. But red also because I'm growing weary of getting dropped on because people just don't see me coming. The photos below don't do it justice, as the black seems to absorb the shadows necessary to reveal the contours. But, I'm stoked at how the board turned out and can't wait to get it in the water.
Attachments
IMG_3058.JPG
IMG_3056.JPG
IMG_3060.JPG
IMG_3064.JPG
IMG_3065.JPG
"This is a paipo site...isn't it?"
www.tp4surf.com

SJB
Big Wave Charger
Posts: 221
Joined: Fri Sep 30, 2011 12:39 am
City: Santa Barbara
State or Province: CAL
Country: USA
Location: Santa Barbara

Re: TBG5

Unread post by SJB » Fri Sep 08, 2017 8:06 pm

Very cool. If we ever get a swell again let me know where and when. Would love to test drive.

CHRISPI
Big Wave Charger
Posts: 301
Joined: Sun Dec 28, 2014 2:48 pm
City: Durban
State or Province: Natals
Country: South Africa

Re: TBG5

Unread post by CHRISPI » Sat Sep 09, 2017 5:18 am

Very nice love the rails

User avatar
bgreen
Big Wave Charger
Posts: 1051
Joined: Fri Aug 19, 2011 5:17 pm
City: Brisbane
State or Province: Qld
Country: Oz
Contact:

Re: TBG5

Unread post by bgreen » Sat Sep 09, 2017 11:37 am

Nomas,

Thanks. The black does make it hard to see the details. It will be interesting to hear how it rides.

Aesthetically, the style of nose doesn't appeal, but if it works, that's the real test. It looks like there is fair amount of rocker in this board.

Bob

User avatar
nomastomas
Big Wave Charger
Posts: 515
Joined: Thu Nov 17, 2011 2:30 am
City: Ojai
State or Province: CA
Country: USA
Interests: Surfing, cycling and fishing
Location: Ojai, CA
Contact:

Re: TBG5

Unread post by nomastomas » Tue Sep 12, 2017 12:59 am

Yeah, I boosted the nose to 3" and the tail to 7/8" at the stringer, but the V in the tail adding another 1/8" to the rail rocker. I also added more curve throughout the bottom, instead of the original, staged rocker. Intent here is to increase turning performance with a more continuous curve, since the board is already plenty fast. I think it will pay off more in larger surf. Although, I'd settle for some chest-high mush right about now.
"This is a paipo site...isn't it?"
www.tp4surf.com

User avatar
nomastomas
Big Wave Charger
Posts: 515
Joined: Thu Nov 17, 2011 2:30 am
City: Ojai
State or Province: CA
Country: USA
Interests: Surfing, cycling and fishing
Location: Ojai, CA
Contact:

Re: TBG5

Unread post by nomastomas » Wed Sep 13, 2017 11:58 am

So...while I'm waiting for some decent waves to test this thing on, I thought I'd mention something I recently learned about carbon fiber. CF is about 5 times stiffer than S-cloth and 30% lighter. S-cloth actually has a slightly (6%) higher tensile strength-to-weight ratio and a slightly higher compression-strength-to-weight ratio. So, if you're looking for superior stiffness and lightest weight, carbon fiber is the way to go. But, if your looking for general toughness, S-cloth is the choice. S-cloth also cost about 60% less per yd. But, the "curb appeal" of carbon fiber is undeniable.
Here are some definitions:
Tensile Strength - Ability to resist a force before breaking
Elongation - Ability to stretch before breaking
Stiffness - Ability to resist deflection or deformation before breaking.
Density - weight/volume
"Toughness" - a combination of the first two stated above.

Here's a great video on a comparison between fiberglass, carbon fiber and kevlar https://www.youtube.com/watch?v=KHXVf0SaJpA
Last edited by nomastomas on Sat Sep 23, 2017 9:08 am, edited 1 time in total.
"This is a paipo site...isn't it?"
www.tp4surf.com

belly rider
Big Wave Charger
Posts: 95
Joined: Thu Jul 31, 2014 5:33 pm
City: Florence
State or Province: Tuscany
Country: Italy
Interests: A True Passion for Paipo & Kneeboards
Location: Italy

Re: TBG5

Unread post by belly rider » Thu Sep 14, 2017 10:19 am

Wow another beauty
FERRARI red that is. :lol: :lol: :lol:
See you soon
its all about the ride

User avatar
nomastomas
Big Wave Charger
Posts: 515
Joined: Thu Nov 17, 2011 2:30 am
City: Ojai
State or Province: CA
Country: USA
Interests: Surfing, cycling and fishing
Location: Ojai, CA
Contact:

Re: TBG5

Unread post by nomastomas » Thu Sep 14, 2017 10:29 am

EXACTLY!
"This is a paipo site...isn't it?"
www.tp4surf.com

User avatar
krusher74
Big Wave Charger
Posts: 773
Joined: Wed Nov 07, 2012 3:53 pm
City: easkey
State or Province: co sligo
Country: Ireland
Interests: Surfing, vintage cars and motorbikes
Location: Easky, Co sligo , ireland
Contact:

Re: TBG5

Unread post by krusher74 » Sat Sep 23, 2017 4:14 am

Very exciting design, Would love to try that finless. (maybe try again this winter :? )

User avatar
nomastomas
Big Wave Charger
Posts: 515
Joined: Thu Nov 17, 2011 2:30 am
City: Ojai
State or Province: CA
Country: USA
Interests: Surfing, cycling and fishing
Location: Ojai, CA
Contact:

Re: TBG5

Unread post by nomastomas » Thu Oct 26, 2017 10:14 pm

After sitting in its new bag for over a month, I finally got a chance to ride my ne G5. Here are my first impressions:

Conditions: Glassy, 4ft-5ft beach break, mid-tide rising. SW groundswell, with a touch of NW windswell. Just a little crowded, with a dozen shortboarders of various skill levels competing for waves across two A-frame peaks about 50yds apart.
Performance: Almost identical to the G4 in paddling and duck-diving. Take-offs are the late drop-in variety, again similar to the G4. I thinned the tail on the G5 by moving the thick point forward, which allows the tail to sink more at the tail, providing a more forgiving take-off. (The G5 remains more parallel to the surface regardless of how steep the face on take-off.) Again, like the G4, the G5 immediately engages the wave face and holds. But unlike the G4 where the rider can feel this engagement primarily in the rear ¼ of the tail where the fins are, on the G5, the rider can feel the entire “wetted” rail engaged in the wave face. The G5 rail feels much more engaged to the point that I believe I can reduce fin area, perhaps significantly. (less fin area=less drag=more speed) While as tested (with my favorite quad fin set FCS H2) there was no significant increase in speed noted, but no loss of speed either, despite the fact that the G5 has more rocker on both ends. I did notice that turns were easier on the G5, which I attribute to the continuous rocker of the G5 compared to the staged-rocker of the G4. The ultimate test of the rail performance would be to ride the shape finless.

Summary: The G5 equals or exceed the performance of the G4 in every category. I need to do continued research to optimize ideal fin area for a given wave size.
"This is a paipo site...isn't it?"
www.tp4surf.com

User avatar
bgreen
Big Wave Charger
Posts: 1051
Joined: Fri Aug 19, 2011 5:17 pm
City: Brisbane
State or Province: Qld
Country: Oz
Contact:

Re: TBG5

Unread post by bgreen » Sun Oct 29, 2017 4:25 pm

Hello Nomas,

I was interested in your comment: "I thinned the tail on the G5 by moving the thick point forward".

Do you have a comparative photo of the respective G4 and G5 foils? How far forward is the new version?

Bob

User avatar
nomastomas
Big Wave Charger
Posts: 515
Joined: Thu Nov 17, 2011 2:30 am
City: Ojai
State or Province: CA
Country: USA
Interests: Surfing, cycling and fishing
Location: Ojai, CA
Contact:

Re: TBG5

Unread post by nomastomas » Mon Oct 30, 2017 11:33 am

Comparing foils is difficult because the thickness of the rail masks the centerline thickness. And rail thickness is oftentimes what I use to add or subtract overall volume, so there is no consistent rail thickness shape to shape. I had a 49" G4, but it was 1/2" wider at 22" and 1/4" less thick at 1.75". On this G4, max thickness starts at 15.82" up from the tail and ends at 27.5", while max thickness on the G5 starts at 17.67" up from the tail and ends at 25.81" up. So, about a 3" shift forward.
"This is a paipo site...isn't it?"
www.tp4surf.com

User avatar
bgreen
Big Wave Charger
Posts: 1051
Joined: Fri Aug 19, 2011 5:17 pm
City: Brisbane
State or Province: Qld
Country: Oz
Contact:

Re: TBG5

Unread post by bgreen » Wed Nov 01, 2017 4:13 pm

Nomas,

Thanks. It's interesting to see the shift forward from the original Goddard models which had the thickness way back - now more like a modern standard board foil.

User avatar
nomastomas
Big Wave Charger
Posts: 515
Joined: Thu Nov 17, 2011 2:30 am
City: Ojai
State or Province: CA
Country: USA
Interests: Surfing, cycling and fishing
Location: Ojai, CA
Contact:

Re: TBG5

Unread post by nomastomas » Wed Nov 01, 2017 5:12 pm

tb1.jpg
tb1.jpg (187.61 KiB) Viewed 3892 times
This was my first T-Belly based entirely upon Goddard's work. It was 51" long and almost 3" thick. I found it hard to catch waves and prone to pearling on steep take-offs. I also found that it was not very good at holding into the wave face. It essentially felt too big for me in every dimension. A heavier rider might have had a much different opinion.

Over the next 7 years I made progressive tweaks in the shape, primarily thinning and shortening, but also playing with bottom contours. In each case, these changes were in service of my own biases, creating what I, personally, like to ride. Much of my foil changes have come from observing the shortboarders, with whom I frequently share a peak. Until the moment they stand up, they are essentially prone surfing. So, yes, my foil is now very similar to the common shortboard, albeit in a much shorter length.
Attachments
IMG_3065.JPG
IMG_3057.JPG
"This is a paipo site...isn't it?"
www.tp4surf.com

Post Reply

Who is online

Users browsing this forum: No registered users and 3 guests