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Board » Technical Discussion » Help with polars ( with help of brainaid toolbox)

Posted by
DaniLA


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2018-07-18 10:51:11
2018-07-26 10:23:58 - Help with polars ( with help of brainaid toolbox)
Hi every body,

I am quite new in SOL and real sailing. I started using SOL as a way to practice with planing routes, but I must confess that I am really exited with the game.

I would like to calculate better the SOG in SOL to evaluate the best routes. Using the steer tool is easy to see in the polar tool the SOG when calculating the current turn. But when I want to find the SOG in other part of the map is when I don't really know how to do it.

As far as I have seen, with the polars tool in SOL you are using TWA and TWS. I have seen in http://sol.brainaid.de/sailonline/toolbox/ a .csv file with a table with more TWA and TWS for a given boat than the provided in SOL (helpful links/Boat polars). My problem is that not always there is a TWA and TWS that is calculated in this file (for example TWA = 55.5, TSP = 4.8, SOG = ??). Do you know how can I calculate the SOG (for SOL) given TWA and TWS?

Thank you so much!!
Posted by
sol


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2008-08-14 11:08:14
2018-07-28 08:34:50 - Re: Help with polars ( with help of brainaid toolbox)
@DaniLA

I never calculate boat SOG. All the arithmetic has already been done and resulted in the polar (or polar tool as you name it?).

If you move the cursor over the map you see in the right upper corner windspeed & direction.

You can check on the polar what SOG, assuming the same twa, these numbers would give you.

If you want to know the wind conditions on that spot in six hours first move the weatherforecast slider 6 hours in the future and then repeat the same.

There are more knowledgable, real, sol'ers who are experts in polars etc. Maybe they will answer to your questions.

Maybe a tool like 'kroppyer's SPINNACER gives more accurate answer to your speed question.
(http://sol.kroppyer.nl/?spinnacer)

An idea of some values and formulas you need for calculating you can find here?
http://www.samoht.com/spa/boatperfcalc.htm

Lacsareno


--- Last Edited by sol at 2018-07-30 11:09:40 ---
Posted by
kroppyer


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2018-08-29 18:53:01 - Re: Help with polars ( with help of brainaid toolbox)
I started developing SPINNACER exactly with this in mind: I needed a way to accurately determine SOG at a given windspeed and angle and use this in calculations.

SPINNACER offers both a graphical as a numerical way to do this. It may be a bit cumbersome at the start, but it sounds like this is the tool you're looking for.

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