Beneteau First 30 - Keel position (Lead)

[gonzo]

The yacht, while trying to surf, trips over its hull and trips over its large keel.

And tries to capsize.

It is not trying to "surf". The boat is clearly heaving-to, which is completely different. At no point it trips over anything.

 

[CarlosK2]

"Is it the keel that is quite forward, or the mast that is quite aft ???"

---

the Keel is quite forward

(A) the hydroDynamic Center of the Keel is forward (!) of the longitudinal position of the Center of Gravity (L_CG) of the Yacht

And -Achtung !-

(B) the Center of Gravity of the Yacht is forward (!) of the Center of Flotation (L_CF)

 

[CarlosK2]

The modern yacht

The modern yacht is born twice

1) It was born around 1930 with a fractional rig, for example:

Tumlare or Tumlaren - Classic Yacht Info https://classicyachtinfo.com/yclass/tumlare-or-tumlaren/

2) And it was born in another way with the Myth of Malham

World’s coolest yachts: The Myth of Malham - Yachting World https://www.yachtingworld.com/yachts-and-gear/worlds-coolest-yachts-the-myth-of-malham-156839

 

[CarlosK2]

The funny thing is that the Myth of Malham ... had the Mast at 44% LWL ...

And the third birth of the modern yacht (1970-) had the mast at 40% LWL ... as in 1860

Defining our species as "homo sapiens" ... is, at this point in the horrible film, a joke in bad taste.

 

[CarlosK2]

Between 1930 and 1970 ...

the Longitudinal position of the center of Flotation moved from 50% LWL to 58% LWL

(and when sailing Downwind in ocean waves, its actual position may be around 60% LWL)

That is, everything (Keel and Mast) would have had to be moved Aft to fit a modern Hull

 

[Night Sky Yachts]

I'm not sure if this locating the keel forward relative to the mast can be called a trend, but I recommend looking at excellent yachts like Pogo RC and JPK 1050 (winner of Fastnet Race). However, this is not a new idea. For example, SWE-96 Victory Challenge in 2007 had her mast located very far after the keel. The methods of Prof. Nomoto and Prof. Gerritsma are a huge simplification of the problem, but still can be helpful for designing conventional yachts.