TBG5

What works and what doesn't. Share design ideas, references and contacts for paipo board builders.
User avatar
rodndtube
Big Wave Charger
Posts: 1158
Joined: Thu Aug 18, 2011 10:34 pm
City: Arbutus Land
State or Province: Maryland
Country: USA
Interests: Waveriding, travel and the Paipo Research Project
Location: Maryland, USA & Where the Waves Are Breaking
Contact:

Re: TBG5

#81

Unread post by rodndtube »

Knees do act like natural shock absorbers. But, I have also noticed that cross-chop/cross-swell tends to create a special scenario when moving at speed in an open ocean wave (meaning one several, several hundred yards out where I have encountered this happening). My body/belly can't do what my knees and legs can do in a standing position.
rodNDtube
"Prone to ride"
I love my papa li`ili`i

"The sea doth wash away all human ills."
-- Euripides.
User avatar
nomastomas
Big Wave Charger
Posts: 597
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

#82

Unread post by nomastomas »

So much for trying to keep a complicated subject simple. So, its not the amount of planing surface per se, but more the characteristics of the planing surface, particularly the relationship of the length of the hull to the width of the hull. Naval architect, Lindsay Lord referred to this as the “aspect ratio” (AR) of the hull. Writing in “The Naval Architecture of Planing Hulls” (a must-read for any budding surfcraft designer. Also, a pretty good sleep-aide) he states:

“The lift and the drag, or the carrying power and the resistance, of a simple plane are combined functions of the effective planing angle, together with those characteristics inherent in the particular plane’s beam (to) length proportion or aspect ratio…In other words, while increasing speeds require the displacement hull to become progressively narrower, the planing hull moving at high speed requires the widest possible beam. To simplify still further, the displacement hull can improve speed only with added length; the planing hull requires added beam. The beam-length proportion is fundamental as a controlling factor in (planing) hull performance. This relationship, as indicated by the aspect ratio, is basic in the estimate of potential lifting power…” Lord found that an aspect ratio of 0.40 was the best, and that an aspect ratio around 0.20 “..compared with wider bottoms, is inferior on every count. The resistance is higher at all speeds, the lift is low, the stability poor, the longitudinal moment excessive and the wetted surface reduction almost zero.”

So, to answer your question, consider the aspect ratio of a 9’6”L x 23” W longboard, and the aspect ratio of a 49” L x 23” W prone-board. The AR for the longboard is 0.20 (23/114), while the AR for the prone-board is 0.47 (23/49). According to Lord, the prone-board is better at generating lift than the longboard. It is for this reason that big wave guns opt for an aspect ratio of 0.16 (19.5/120). In waves of consequence, lift is a quality to be avoided.
"This is a paipo site...isn't it?"
www.tp4surf.com
User avatar
rodndtube
Big Wave Charger
Posts: 1158
Joined: Thu Aug 18, 2011 10:34 pm
City: Arbutus Land
State or Province: Maryland
Country: USA
Interests: Waveriding, travel and the Paipo Research Project
Location: Maryland, USA & Where the Waves Are Breaking
Contact:

Re: TBG5

#83

Unread post by rodndtube »

So, my 50 inch board would need to be 10 inches wide to avoid all that lift and skipping as a planning. LOL, at 10 inches wide it would no longer be a planning hull but a displacement hull ;)
rodNDtube
"Prone to ride"
I love my papa li`ili`i

"The sea doth wash away all human ills."
-- Euripides.
GeoffreyLevens
Big Wave Charger
Posts: 384
Joined: Sat Sep 17, 2011 9:58 am
City: Paonia
State or Province: Colorado
Country: USA
Location: Paonia, Colorado
Contact:

Re: TBG5

#84

Unread post by GeoffreyLevens »

Can't remember who said/where I read, but quite a few years back I remember reading that GG style hulls, at very high speeds, will plain up on smaller and smaller area along the midline and lift out of the water. Not likely in continental US type waves, think Sunset, HI beach West swell type power.

Stand-up boards, I have rocked (small amount) rail to rail to "calm" bounce or skip in choppy surf and it seemed to help quite a bit at maintaining control
GeoffreyLevens
Big Wave Charger
Posts: 384
Joined: Sat Sep 17, 2011 9:58 am
City: Paonia
State or Province: Colorado
Country: USA
Location: Paonia, Colorado
Contact:

Re: TBG5

#85

Unread post by GeoffreyLevens »

Rod your theoretical 50" X 10" board would make a good weapon for hunting/spearing small game. Just make sure the nose has a nice, sharp point
User avatar
nomastomas
Big Wave Charger
Posts: 597
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

#86

Unread post by nomastomas »

The load must also be taken into consideration as well as its counterpart buoyancy. And speed, too. Then, of course, there is the impact of form drag produced, not just by the legs but by other body parts, arms, hips, etc, that may be hanging over the outline. I thought all that was obvious? And, while I'm sure there is a mathematical way to take all of these variables into account and determine the ultimate aspect ratio for a given length at a given speed with a given load, I am no mathematician nor engineer.

What I take away from Lord's work is that, with a planing hull, the 0.40 aspect ratio provides the highest potential for lift for a given length. A decrease in aspect ratio from 0.40 results in a decrease in planing efficiency and lift. Therefore, one way to reduce lift is to decrease the aspect ratio by narrowing the width. Without benefit of a trained engineer, I'll have to utilize a trial-and-error approach to determine the ultimate aspect ratio, reducing width while knowing that I will need to maintain a specific volume for my body weight and a minimum width (the width of my shoulders and hips). Reducing the aspect ratio reduces the hull's efficiency of planing which increases drag, reduces speed and the resultant lift. But there are other ways of reducing speed which in turn will reduce lift. I can introduce drag, for example, by increasing fin area, dragging my legs or by introducing drag producing features to the bottom contour, e.g. increase rocker.
"This is a paipo site...isn't it?"
www.tp4surf.com
User avatar
krusher74
Big Wave Charger
Posts: 842
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

#87

Unread post by krusher74 »

rodndtube wrote: Thu May 16, 2019 2:42 pm Knees do act like natural shock absorbers. My body/belly can't do what my knees and legs can do in a standing position.
one reason I'm such a proponent of boards shorter than most people seem to ride it that I like to ride with about a 90 degree angle on my rail arm elbow while holding the nose. This I feel is the most optimum position for up and down shock absorption through your shoulder and lifts your chest/belly much further off the board. I see guys outstretched for the nose look very static and unable vary there position quickly to maneuver the board.

You can feel this effect my lying on the floor with both forearms on the floor in front of you propping you up and elbows at 90 degrees. Feel how easy it is to move up and down etc , now slide your hands further and further forward and you will feel how much less mobility you have and the more your chest/stomach makes you immobile. This immobility makes it much harder to dampen chop.
User avatar
nomastomas
Big Wave Charger
Posts: 597
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

#88

Unread post by nomastomas »

I totally agree with your arm position/location, but I design my boards to provide a little support for the upper thigh when ridden in this position. The tailblock is about 6" below the natural break at the hip when ridden in the position you describe. It requires a slight shift forward to go from kick-paddling position to riding position. I know I'm in the correct position when my hands are on the nose and my elbows/forearms are on the deck. The bit of support by the tailblock makes it easier for me to keep my legs from dragging.
"This is a paipo site...isn't it?"
www.tp4surf.com
User avatar
nomastomas
Big Wave Charger
Posts: 597
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

#89

Unread post by nomastomas »

Here are five G5s that are headed to Florida. This photo shows the scalability of the G5 design. Intended riders range in height from 6'2" to 5'6", and in weight from 230lb to 140lbs. Lengths are 52", 50", 46" and 45".
Attachments
IMG_4657.JPG
"This is a paipo site...isn't it?"
www.tp4surf.com
CHRISPI
Big Wave Charger
Posts: 340
Joined: Sun Dec 28, 2014 2:48 pm
City: Durban
State or Province: Natals
Country: South Africa

Re: TBG5

#90

Unread post by CHRISPI »

Very nice boards. Keel V bottom is the way to go.
belly rider
Big Wave Charger
Posts: 111
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

#91

Unread post by belly rider »

great looking line up of Floridian boards
its all about the ride
User avatar
krusher74
Big Wave Charger
Posts: 842
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

#92

Unread post by krusher74 »

Great to see plenty of interesting paipos and 5! being ordered.
User avatar
rodndtube
Big Wave Charger
Posts: 1158
Joined: Thu Aug 18, 2011 10:34 pm
City: Arbutus Land
State or Province: Maryland
Country: USA
Interests: Waveriding, travel and the Paipo Research Project
Location: Maryland, USA & Where the Waves Are Breaking
Contact:

Re: TBG5

#93

Unread post by rodndtube »

Where in Florida are they headed?
rodNDtube
"Prone to ride"
I love my papa li`ili`i

"The sea doth wash away all human ills."
-- Euripides.
User avatar
krusher74
Big Wave Charger
Posts: 842
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

#94

Unread post by krusher74 »

Just noticed they are all leg leash plugs, was that by order or you dont like arm leashes?
CHRISPI
Big Wave Charger
Posts: 340
Joined: Sun Dec 28, 2014 2:48 pm
City: Durban
State or Province: Natals
Country: South Africa

Re: TBG5

#95

Unread post by CHRISPI »

Arm leashes specially elbow make boards with pointy bits come back to fast and hard.
User avatar
nomastomas
Big Wave Charger
Posts: 597
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

#96

Unread post by nomastomas »

Rod - After last minute discussion with customer, 3 went to Laguna, CA and 2 went to Oldsmar, FL

Krusher - It's what I recommend for hard surface boards with hard fins.
"This is a paipo site...isn't it?"
www.tp4surf.com
User avatar
krusher74
Big Wave Charger
Posts: 842
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

#97

Unread post by krusher74 »

CHRISPI wrote: Mon Oct 28, 2019 5:36 am Arm leashes specially elbow make boards with pointy bits come back to fast and hard.
That's not my experience of using them, but I guess they work differently for everyone. Dragging a leg leash just sounds horrific! lol
User avatar
nomastomas
Big Wave Charger
Posts: 597
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

#98

Unread post by nomastomas »

No...watching your board bounce around on the rocks is horrific. :o
"This is a paipo site...isn't it?"
www.tp4surf.com
User avatar
rodndtube
Big Wave Charger
Posts: 1158
Joined: Thu Aug 18, 2011 10:34 pm
City: Arbutus Land
State or Province: Maryland
Country: USA
Interests: Waveriding, travel and the Paipo Research Project
Location: Maryland, USA & Where the Waves Are Breaking
Contact:

Re: TBG5

#99

Unread post by rodndtube »

krusher74 wrote: Wed Oct 30, 2019 4:33 pm
CHRISPI wrote: Mon Oct 28, 2019 5:36 am Arm leashes specially elbow make boards with pointy bits come back to fast and hard.
That's not my experience of using them, but I guess they work differently for everyone. Dragging a leg leash just sounds horrific! lol
I'm with Krusher on this one but it is a matter of preference. And, I'd rather untangle with my hands and arms in close proximity. There are pluses and minuses in each approach. I do tend to use a longer leash than many bodyboarders/paipo boarders, 5 ft in smaller surf, 6 ft in larger surf, and I don't like coil leashes as they seem to snap back more... I'd rather a leash stretch out even if it mean having to buy a new leash.
rodNDtube
"Prone to ride"
I love my papa li`ili`i

"The sea doth wash away all human ills."
-- Euripides.
belly rider
Big Wave Charger
Posts: 111
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

#100

Unread post by belly rider »

I premer leg leashes and buy the 5' COMPETITION extra thin one
Never really experienced tangling as I am tall 6'2" and my long legs probably keep the leash stretched enough to avoid wrapping around
its all about the ride
Post Reply

Who is online

Users browsing this forum: No registered users and 40 guests