Calculating your BARG Factor.

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BWalnut said..

FranP said..

BWalnut said..

patronus said..
Moved from 3.4 to 3.7 and feels like 0.3m less sail area needed in light winds. Unlike in windsurfing I notice change in a few kg bodyweight so multiply rather than add gets that better. I'm 90kg wet on a 90l board.

So, would everyone say it's about time to commit to updating the master plan and transitioning it towards the multiply system?

www.wouzel.com/post/calculating-your-barg-factor

Every "factor" or mathematical coeficient should be easy to interpretate, aligned with a physical characteristic or an understandable board performance metric... if not it's just a mathematical number with several correlations, hard to understand.

I think most people understand aspect ratio at this point. Everyone definitely understands volume and guild factors have been around for a very long time. This is just aspect ratio and volume together.

Of course, both volume and AR are in the BARG formula..... but what's the meaningful and easy interpretation ?

For example,
-Foil AR determines (somehow) the glide and turning capabilities, although there are other factors (foil profile, angle, etc.).
-Foil thickness determines (somehow) glide and speed limits.
-Board AR width determines (somehow) speed and board stability etc..

.....I like the challenge to build up a new comprehensive board coeficient, but how to interpretate the BARG factor ?


------------------ Here's a comprehensive set of criteria a physical factor should have (by CHAT GPT)

To define a physical coefficient or factor in a way that is useful, understandable, and easy to interpret, several guiding principles should be followed:

1. Clarity of Definition
Precise Definition: The coefficient or factor must be clearly defined with respect to the physical phenomena it represents. Ambiguities or vague descriptions should be avoided.
Consistent Terminology: Use consistent and standard terminology from the relevant field to ensure the coefficient is aligned with established concepts.

2. Dimensional Consistency
Units and Dimensions: The coefficient should have clearly defined units and dimensional consistency according to dimensional analysis. For example, in physics, units like meters, seconds, and kilograms should correspond to the coefficient's physical meaning.
SI Units: Prefer using the International System of Units (SI) as it is widely recognized and simplifies conversion and comparison between different systems.

3. Relevance and Applicability
Contextual Relevance: The coefficient should be applicable to the situation it is designed for. It should address a real physical problem or relation and be widely applicable in different cases.
Domain of Validity: It's important to specify the conditions under which the coefficient is valid, such as certain temperature ranges, pressures, or other physical limits. If it is a constant in specific cases but varies in others, this should be made clear.

4. Simplification
Meaningful Simplification: Simplify the coefficient to the extent possible without losing critical physical meaning. Over-complication in definition or formulation may lead to misunderstanding.
Logical Assumptions: Include any assumptions that allow simplification. This provides clarity on when the coefficient can be used without over-complexity.

5. Intuitive Interpretation
Link to Physical Concepts: The coefficient should have a clear physical interpretation. For instance, the gravitational constant
??
G relates directly to the strength of gravity, making its meaning more intuitive for users.
Positive or Negative Significance: If the sign of the coefficient matters, clearly explain what a positive or negative value represents. For example, in thermodynamics, a negative coefficient of thermal expansion indicates contraction with temperature rise.

6. Measurability
Experimental or Theoretical Basis: The coefficient should be defined such that it is measurable either experimentally or through theoretical models. It should correspond to quantities that can be observed or calculated accurately.
Reproducibility: The methods used to determine the coefficient should allow others to reproduce the results under similar conditions.

7. Scalability and Transferability
Scalability: The coefficient should be applicable across different scales of the physical system, or the limitations should be clearly defined.
Transferability: Ensure that the coefficient can be adapted for use across different fields or systems, if applicable, by ensuring its definition is flexible but precise.

8. Mathematical Consistency
Logical Formulation: The coefficient should fit logically within equations and physical models. It should respect the mathematical structures of the theories or systems it applies to.
Non-Redundancy: Avoid defining coefficients that are redundant or can be derived from others. It should represent a unique physical quantity.

9. Simplicity in Usage
Ease of Use: The coefficient should not require complex manipulation to use. It should seamlessly fit into the equations or models it supports.
Common Understanding: If possible, the coefficient should be one that practitioners in the field can quickly recognize and understand, minimizing the need for extensive background explanation.

10. Error Tolerance and Robustness
Sensitivity: Explain the sensitivity of the coefficient to changes in other variables. A useful coefficient is robust and does not wildly fluctuate with small variations in the system.
Uncertainty Estimation: If the coefficient is derived from experimental data, provide an estimate of its uncertainty or confidence level.
By adhering to these principles, a physical coefficient or factor can be defined in a way that promotes ease of understanding, usefulness in practice, and clarity in communication within the scientific community.

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northy1 said..
@BWalnut - how much change in the factor makes a material difference in the water do you think?

ive just done the maths, and my fone rocket s 70, has a pretty low BARGF it seems compared to many other boards ive looked at


So reading the above, the new Army ML boards (ie 75) for example would get going a lot easier than mine? 4.53 vs 3.38?
And if i wanted a low wind board to complement my 70, does this calc help me choose at all eg the Fone ML 105?

PS
i am 85kg in the buff, so should i use 90+kg for when in 5mm suit, boots,hood etc ??

Good questions.
3.38 isn't bad, but most wouldn't consider that easy to take off on. I had a 3.83 that I thought was alright. I ride 4.5 every day because it's so much better though. I also have a 5.39 that's even easier to take off on but not as fun in the air. More lightwind specialty.

Yes to the armstrong question.

I'm 85kg in the buff as well and all that matters is that you start tracking how your own BARGF works for you. You can run the numbers with wet gear weight or not, but just always reference your own experiences.

From left to right with BAR+GF and BAR*GF stats showing the trends:
6'6"x18"90l = Extreme Light Wind 5.39 BAR*GF = 4.59
5'10"x20"x85l = Everyday 4.5 BAR*GF = 3.5
5'2"x20"x67.5l = Stronger winds 3.88 BAR*GF = 2.46

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greg87foil said..

Jafalex said..
I ended up demo'ing the Armstrong ML75, it was everything I wanted in a board, an amazing ride, I pulled the trigger there and then. Stoked. only thing is it doesn't fit in the boot of the car, so I'm on the hunt for a van, any recommendations?

.jokes

Thanks for all the help picking the ride

nice one, they're nice boards indeed.

I ended up receiving my custom Appletree, but they messed up some of the custom specifications I wanted so it's going back and I have to wait another 2 months until they make me one again, this time to the proper specs...

annoying, but from what I saw in the box it's a very very nice shape..

Finally got the custom Appleslice v3 with correct specs! Looking super good and can't wait to get it in the water!L = 5'4"
W= 20"
Volume = 65L

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Relapse said..

greg87foil said..

greg87foil said..

Jafalex said..
I ended up demo'ing the Armstrong ML75, it was everything I wanted in a board, an amazing ride, I pulled the trigger there and then. Stoked. only thing is it doesn't fit in the boot of the car, so I'm on the hunt for a van, any recommendations?

.jokes

Thanks for all the help picking the ride

nice one, they're nice boards indeed.

I ended up receiving my custom Appletree, but they messed up some of the custom specifications I wanted so it's going back and I have to wait another 2 months until they make me one again, this time to the proper specs...

annoying, but from what I saw in the box it's a very very nice shape..

Finally got the custom Appleslice v3 with correct specs! Looking super good and can't wait to get it in the water!L = 5'4"
W= 20"
Volume = 65L

You in Oz Greg? A few of desperately waiting for ours to arrive

Europe

Select to expand quote

greg87foil said..

greg87foil said..

Jafalex said..
I ended up demo'ing the Armstrong ML75, it was everything I wanted in a board, an amazing ride, I pulled the trigger there and then. Stoked. only thing is it doesn't fit in the boot of the car, so I'm on the hunt for a van, any recommendations?

.jokes

Thanks for all the help picking the ride

nice one, they're nice boards indeed.

I ended up receiving my custom Appletree, but they messed up some of the custom specifications I wanted so it's going back and I have to wait another 2 months until they make me one again, this time to the proper specs...

annoying, but from what I saw in the box it's a very very nice shape..

Finally got the custom Appleslice v3 with correct specs! Looking super good and can't wait to get it in the water!L = 5'4"
W= 20"
Volume = 65L

@Greg awesome ?? ?? ??

I had a conversation with Appletree this week about a custom made Slice V3 as well. I asked for similar dimensions like the Omen 84L. I got an offer but was also told to be patient for spring where we likely will see a ML board announcement from Appletree...

Select to expand quote

Jafalex said..

Frankenbeutel said..

greg87foil said..

greg87foil said..

Jafalex said..
I ended up demo'ing the Armstrong ML75, it was everything I wanted in a board, an amazing ride, I pulled the trigger there and then. Stoked. only thing is it doesn't fit in the boot of the car, so I'm on the hunt for a van, any recommendations?

.jokes

Thanks for all the help picking the ride

nice one, they're nice boards indeed.

I ended up receiving my custom Appletree, but they messed up some of the custom specifications I wanted so it's going back and I have to wait another 2 months until they make me one again, this time to the proper specs...

annoying, but from what I saw in the box it's a very very nice shape..

Finally got the custom Appleslice v3 with correct specs! Looking super good and can't wait to get it in the water!L = 5'4"
W= 20"
Volume = 65L

@Greg awesome ?? ?? ??

I had a conversation with Appletree this week about a custom made Slice V3 as well. I asked for similar dimensions like the Omen 84L. I got an offer but was also told to be patient for spring where we likely will see a ML board announcement from Appletree...

I heard rumours of new DW Prone sizes.

Could also be the case. As I asked if those boards would fit to my needs 5'7x21 I was told longer and narrower. Now I am still thinking about Custom made in the mentioned size, or a standard Slice in 80L