Less is More

Dyneema and Knots

Presenting a New Hitch : the EStar-XX (based on EStar Hitch) - Page 2 - Cruisers & Sailing Forums https://www.cruisersforum.com/forums/f116/presenting-a-new-hitch-the-estar-xx-based-on-estar-hitch-127822-2.html

 

Some people are lazy. Look at car washes......

 

This

This cost €12-€14

I have to do this maneuver ten times and it would cost 120-140 euros, when on top of that it's beautiful and entertaining to do

---

The tool used If you go to a nautical shop they might ask for... I don't know, an outrageous amount

But you can cut a 7 euro knitting needle

 

Dyneema rope 4 mm x 60 cm = € 0.7
Dyneema shackle: € 16

 

In summary

The safety of a small yacht, between 1 and 10 tons, on high seas does not depend on its size

Creating different categories (A: Ocean, B: offshore, C: Coastal) of small yachts based on size is ridiculous

And

Many yachts sailing downwind suffer from the explosive combination of four elements

1) with 1-2 people on board, without a large crew, they are very slow in relation to their length, sometimes, often, not even reaching 0.4 Froude and even sailing at 0.3 Froude, and on top of that with the wind right behind them

2A) Longitudinal imbalance: the center of gravity is forward of the center of flotation, which is where the Pitch axis passes, and on top of that, the wave coming from astern and/or the heel moves the center of flotation even further aft

center of flotation calculation and implications? https://www.boatdesign.net/threads/center-of-flotation-calculation-and-implications.30857/

And to top it all off, the vertical component of the wave force is applied to the center of flotation or, if the yacht is not tiny, aft of the center of flotation

Conclusion: rapid and/or deep Pitch

2B) And furthermore, when the yacht heels, the center of buoyancy moves aft, meaning the bow drops, for example by one degree, something known since 1880: "heavy quarters"

3) Two degrees (-2°) of bow down is enough to drive Mr. Max Michael Munk crazy

On a yacht, we can encounter three versions of Munk's Moment

A) due to leeway/yaw
B) due to leeway/yaw + roll/heel
C) due to leeway/yaw + roll/heel + pitch

And

Munk_C = aprox. => 2 x Munk_B

4) To make matters worse, the hydrodynamic center of a very efficient modern Keel is located forward of the yacht's center of gravity, where the Yaw axis of rotation passes

 

and

5) the orbital current of the wave

If the yacht is sailing at 7 knots and the orbital current of the wave is 3 knots, the water flow at the rudder blade is 4 knots and at the bow of the yacht is 7 knots, or the rudder blade feels 7 knots and the bow 11 knots, and in the worst case the rudder blade feels 4 knots and the bow 11 knots, and in any case the forces depend on the square of the speeds

 

A 1-ton, 5.99-meter WindSurf board Plywood Epoxy ...

I think it's the smallest possible yacht ... and the biggest dinghy

An ideal boat for 1 old sailor, which would also be the ideal boat for 1 young ocean adventurer

An old-man's boat, a kid's dream boat

 

& your malevolent neighbour can cut it with a pocket knife...

 

Experience, numerical calculations, and the Southampton wave tank all agree on the diagnosis:

The bow dips, then the hull's yaw moment (the Munk moment) skyrockets, and to top it all off, a keel trips the yacht.

The helmsman is exhausted, the autopilot fails, the yacht lists to regain its balance like a boxer knocked down on the canvas, and dishes fly around in the galley. In short: no enjoyment.

 

You have convinced me........perhaps i should take up fly fishing?

 

Eric Sponberg ... Bagatelle

Bagatelle https://ericwsponberg.com/boat-designs/bagatelle/

Incredible, amazing, what a marvel !

Achieving 20 square meters per ton is extremely difficult or incredibly expensive beyond 6 meters in length

The law of the square and the cube is relentless with sailboats

And the Mini Transat-type solution with a gigantic beam compromises passive safety: let's not forget that current Mini Transats cross the Atlantic... accompanied by adults

A small boat in which I would feel at ease at home if a nephew, son, or grandson were sailing alone

Speed is safety because it allows you to sail in harmony with the waves

 

Andrew Claughton

Racing on the high seas: leading yacht designer reveals engineering challenges behind the America's Cup | University of Southampton https://www.southampton.ac.uk/news/2007/11/yacht-designer-reveals-engineering-challenges.page

(I'm including this link because I can't find a better one)

Southampton Wave Tank

- "the traditional design was quite easy to control [radio-controlled models] (...) the ease of planing and control in the traditional models was a striking surprise"

Experience, numerical calculations, and the Southampton wave tank ...

All agree on the same diagnosis:

A yacht is sailing slowly, its bow dips, Mr. Max Michael Munk goes completely mad (Hull hydroDynamic Yaw Moment)

Max Munk - Wikipedia https://en.wikipedia.org/wiki/Max_Munk

And to top it all off, the yacht hits a massive modern Keel, flips over, and capsizes.

 

A small boat, and therefore with enough power to sail at 0.5 Froude and "create hydrodynamic Lift at the bow" (Andrew Claughton) and with "neutralized Keel" (CarlosK2) is a good idea

 

+ 2°

A still photograph captures the moment when a Ocean Wave carries the small boat away in its powerful arms.

 

1) We've sent Mr. Max Michael Munk to bed to sleep peacefully: there are no lateral high pressures at the bow, and with a wide stern and the water flowing straight out without curves, no lateral low pressures are created

2) The enormous centerboard is neutral; its gigantic lateral force (if the boat yaws at high speed) has no leverage arm, or the leverage arm is minuscule because its hydrodynamic center is located below the longitudinal position of the center of gravity

3) With stable balance on all three axes (Roll, Yaw, Pitch) two good, well-sized rudder blades only have to compensate for the imbalance created by the sails

4) The boat can fly at the Wave Celerity in harmonie Surf riding the Ocean Wave