Some questions on polars and upwind/downwind performance

I cannot help you with a spreadsheet Goetz, but I am aware that the excellent free and open source OpenCPN boat management software has a "Polars" plugin that might do what you want.
Polar Plugin https://opencpn.org/OpenCPN/plugins/polar.html

 

If this can help you : I developed myself a VPP for sailboat on Open Office Calc spreadsheet (an Excel équivalent), here below, use the last 3,4 version in quote#2 :
Gene-Hull Sailboat 3.3 and its post applications Gene-Stab and Gene-VPP https://www.boatdesign.net/threads/gene-hull-sailboat-3-3-and-its-post-applications-gene-stab-and-gene-vpp.67842/

 

Dear Helmut, thanks I lot. I use OpenCPN as a secondary navigation system but never went into routing so I was not aware that you could "abuse" the Polar Diagram Plugin just for creating a VPP Polar Diagram. I tried with a few data points and - perfect. Thank you!

 

Dear Dolfiman - thank you. Looks like many sleepless nights to program. As I have already a setup of data points (TWA and STW) and "just" wand to get a polar diagram your very impressive tool is a bit "overkill".

 

Question number 1

Draft

Folkboat draft = 1.16 m

The ability to sail close-hauled (for example 45° TWA) Upwind depends largely on the square (!) of the draft

Question number 2

Sailing with the wind is more complicated than it seems, starting with the simple reason that it reduces the speed of the wind reaching the sailboat: the so-called apparent wind, which might be better called the effective wind

 

Regarding surfing

We have

A) The stern-lift effect, a marvel for a yacht sailing at 0.5 Froude with the hull at +2° up ... A disaster for a slow yacht sailing at 0.35 Froude (Hull trim +/-0°) and even more so if, due to longitudinal imbalance, it's prone to rapid and/or deep pitching

B) The Froude-Krylov force, which in a small sailboat is best forgotten because perhaps it's a small, insignificant, or even zero quantity—I don't know. This summer I had a long, entertaining, and fun discussion with DeepSeek, and the matter is confusing

C) Mr. Isaac Newton, which is the crux of the matter: Propulsive force enjoyed by the yacht = mass of the yacht x 9.8 x sine of the wave angle = Newtons

 

While it's true that "Surf gliding is surf riding in bigger waves," I still think it's useful to distinguish between two cases:

1) When the wavelength of the wave is between one and two times the length of the yacht, in this case, A and B are important, and perhaps even for small yachts, the Froude-Krylov model of surf riding for large ships could be applied. My experience sailing my old Mini Transat is that surf riding can begin with tiny waves

2) Enormous Ocean Waves, where the key factor is the mass of the yacht in kilograms x 9.8 x sine of the wave = Newtons

Why my heavy Yacht surf so fast

Why does my boat surf so fast? https://www.boatdesign.net/threads/why-does-my-boat-surf-so-fast.50195/

Because ... Sir Isaac Newton

 

"the old man and the sea"

2.4 tons, 19.19 feet LWL
heading for the Canary Islands

It was sailing at 5 knots and then surfed, reaching 10 knots

It was sailing at 5.5 knots and surfed reaching 12 knots

It was sailing at 6 knots and surfed reaching 14 knots

And finally, it was sailing at 7 knots and performed a tremendous 45-second Surf at 20.5 knots over the bottom (GPS, SOG) which over the water was perhaps 20 or maybe 24 knots

I insist: the surprising thing wasn't the speed reached

The amazing thing is that it didn't flip over three times like a church bell

The incredible thing is that it Surfed again and again with complete safety, controlled by a pilot with little more brainpower than a crystal radio ... thanks to the stable hydrodynamic balance on all three axes: Roll, Yaw, Pitch

 

"Surf-riding phenomenon occurs when a ship sailing in following waves is accelerated to wave celerity"

https://www.sciencedirect.com/science/article/abs/pii/S0029801820309197

(Poor millionaires sailing on yachts: 10-15 Tons miniature merchant ships)

 

(B) the "wave-induced surge force" ... is the horizontal component of the Froude-Krylov force

On the other hand (A) if the stern of a sailboat traveling at 0.40-0.50 Froude is raised, the resistance decreases

In other words, on a small sailboat, both of these factors can release the boat from its displacement regime and launch it into planing-surfing => 0.60 Froude

And this occurs in a benign environment: with small waves

And with very big large ocean waves, the boat glides, propelled by the all-powerful Force of the Earth, in a similar way (though not exactly) like in this video, (because this is a very slow wave created by a rock near the shore):

 

On a small yacht, even the smallest one (1 ton) a single crew member can't trim the hull like on a dinghy without a ballasted Keel

In that video, the girl has shifted the center of gravity dramatically, perhaps to 70-75% (!?) of the LWL

On a yacht, hull trim for good surfing must be hydrodynamic

1) High pressure as in the video: hydroDynamic Lift thanks to a (1A) flat surface and (1B) good beam

2) Low pressure (suction) under the stern (as in this video where they subject an old ship to an impossible speed):



3) Or a combination of high pressure under the bow and low pressure, suction, under the stern

This creates a nice equilibrium: the wave lifts the stern, the boat accelerates and lifts the bow, and the stern dips and settles into the wave, riding it

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Note that since about 1880 the obsession has been that the stern does not sink, because it increases resistance

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Question: Could the angle of attack and hull trim be optimized to increase speed?

That's a question for the world of high-performance racing, beyond the capabilities of Excel spreadsheets and 1925 fluid mechanics, and outside my practical interests.

 

TWS: 30 knots
AWS: 16 knots
Wind Force: 885 Newtons
Sir Isaac Newton: 2241 Newtons
Wave: 12°
SailBoat Speed: 20 knots
Force Froude-Krylov: irrelevant in this case (DeepSeek and Carlos consensus)

The question of speed is ultimately irrelevant because the maximum speed (unless the sailboat is monstrously powerful) is the speed of the wave

And what might interest us is how long you can ride the wave, and that's extremely complicated because the sweet spot for surfing is very small: on a 77-meter wave, the good zone is perhaps only a little over 12 meters

More interesting is whether you catch many waves or just a few.

And above all, the most important thing, I think, is good behaviour and functional enjoyment

 

The maximum speed reached with Force 7 waves is typically 19-20 knots, which is the speed of a young F7 wave

This Mini Transat Pogo 2 reaches a similar top speed to the old 2.4-ton boat bound for the Canary Islands

What changes is: the number of waves caught, the duration of the surf, and the speed in the trough, and therefore the average speed

This isn't so crucial, either

19 days to cross the Atlantic, 1979-1989 Mini Transat

17 days and 6 hours for the Scow 747 "Magnum" 2011 Mini Transat

I'm interested in speed because the waves are very fast; that is, I'm interested in it as a component of safety, comfort, pleasure, and functional and technical-scientific beauty.

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To put it another way: the Mini Transats of 1979-1989 surfed beautifully

Planing on flat using brute force isn't an interesting goal outside the world of high-level competition

Planing is one thing; planing-gliding-surfing well in Waves is another—something that all boats, big and small, heavy and light, motorboats and sailboats, should be able to do.

The waves are out there, surfing is the way

 

It looks like other people have provided you with better solutions, but here's a sample of my spreadsheet, based on published data from the HR 44.

As you said, you can just copy and paste the data you have into the top table on the "HR Data" sheet and get a polar for that data. Unfortunately, the spreadsheet is "brittle" in that the data has to be in exactly the same format--i.e., speeds at 6, 8 10, 12, 14, 16, 20, 25, and 30 knots for the same TWAs. Your data likely won't be in exactly that format, which would mean reverse engineering the spreadsheet a little.

 

Simplifying

The effective Froude-Krylov Force on a moving yacht can be, for example, 0.3 (Pitch) and 0.2 (Wave-induced Surge) times the Froude-Krylov Force calculated for a stationary object

While sailing, we feel the approaching wave push the stern upwards and give us a forward thrust

A yacht sailing at a speed of 0.5 Froude is sailing on what could be described as a hydrostatic wedge (W) of water piled up in a small mound, which in turn is shaped by high (H) and low (L) hydrodynamic pressures

And there is a Drag (D) towards the stern that depends on the hull trim (t)

With all this, what I want to say is that the wave coming from the stern takes the yacht out of the semi-displacement zone (0.4-0.6 Froude) and launches it into planing (=> 0.6 Froude) and surf riding