Simplified Froude-Krylov Force

[CarlosK2]

Thomas Harrison Butler in Memoriam

Obviously, if the 1 Ton WindSurf Board is sailing with a gennaker at 17 knots, surfing a wave that's traveling at 20 knots is no mystery

But It's more reassuring to know that the Surfboard will surf well even without great speed, pushed at the beginning by the Froude-Krylov force and propelled by the Almighty Force of the Earth

 

[CarlosK2]

A boat bought second-hand for 4 K Euros surfed big waves (which are not the ones shown in the images) at 14-20 knots, controlled by a clumsy pilot with little brainpower.

What's the point of spending a fortune on a sports yacht only to spend another fortune on an expensive autopilot and not even reach the heights of the classic solutions of those who came before us

A MiniTransat for an old fogey is a practical matter of comfort and safety, and of respect for tradition and things done well with care

 

[CarlosK2]

Pogo 2: 6.5 m, 1000 kg
Pegaso SLK-599: 5.99 m, 800 kg

1000 kg = 800 kg (6.5/5.99)^3

Less is more

with 30 knots of wind, both sail at 17 knots downwind; but the A5 gennaker is much smaller and more comfortable on a rotating bowsprit

Of course the old sailor has to get up from his seat, a cruelty of the designer

 

[CarlosK2]

599 MiniTransat

https://www.histoiredeshalfs.com/Histoire des Minis/599.htm

Pogo 2 Rossinante, Don Quixote's horse

Rocinante - Wikipedia https://en.wikipedia.org/wiki/Rocinante

And "sponsor a child", the child you once were

"(...) what this yacht is really about. She is no more than an old geezer's realisation of a boyhood dream"

(Roger Taylor, MingMing and the Art of Minimal Ocean Sailing)

 

[Robert Biegler]

CF: Center of Flotation: 58% LWL
Center of Buoyancy at rest/port: 60% [6] LWL

What does the hull shape look like? To get the centre of buoyancy aft of the centre of floatation, the waterplane aft of the centre of floatation needs a higher water plane loading, or greater average draft, than the part of the waterplane forward of the centre of floatation. The ways I know to achieve that would be lots of rocker in the run, a bustle, or an immersed transom. What is your choice?

 

[tropostudio]

At rest they are always aligned vertically The CF will never be forward of the CG; it is basic physics.

Center of Flotation is the centroid of the waterplane area. CF could be ahead of or behind the CG at rest or in motion.
If I'm correct, Carlos2K is using it as a factor in a boat's ability to surf or at least tend toward bow-up on a stern wave.