Six months evolution of new sailboat concept design in pictures

When the year is coming to an end it’s time to look back to see what has happened and plan near future with full speed ahead.

We started in June based on my hand drawn notebooks and here we are now. Next step will be CFD-analysis of the hull and after minor improvements the cutting files for CNC will be produced. And then we are ready for proto series!

Images below describes best the progress of the design project.

At first the most fresh images – end of the year has gone well!

Explorer zentralschwert segelboot

Expedition centreboard sailboat

Frames and stringers added to the design

Design drawing yacht design

Li Yachts sailboat design process

Zero fossil fuels sailboat concept for ocean voyaging

3d-sketch of the hull after one more week of work

Drawing from notebook

Li Yachts 47 sketch

Sketch drawing of ocean expedition sailboat in notebook

Book about the legends of yacht design – discovery from flea market

Friday was dedicated for shopping! But for me as an entrepreneur who will save every cent for this project that meant flea market. That was my Black Friday!

This weeks tragedy was that tea cozy was burned because the tea pot wearing it was placed to a hot stove in the tiny kitchenette! The shopping solved the problems, new cozy and shelves.

The bonus was a book called “You are first” The Story of Olin and Rod Stephens of Sparkman & Stephens by Francis S. Kinney. The flea market was just about to close and I didn’t riffle the book at all. At home I noticed that in the back cover image Olin J. Stephens receives a Marine Aluminum Ocean Racing Trophy in year 1968. That was by chance also the year when our original Li was launched!

The book presents the designs of S&S with lots of interesting images and stories. I read of course first the chapters about centreboard yachts Palawan IV and Finisterre!

Shopping in flea market

Welding with a joy

It’s time to take Li out of the water and winterize. Before that I had to fix my oblivion with her docking rack. When the boat was hoisted first time I just welded supports only with tiny seams when the crane was holding the boat. They had been that way since then. Now it was time to weld them correctly before any accident happens. That was a good example of risk when doing things temporarily!

Welding with Kemppi Minarc 180 Evo

Welding boat's winter rack

Power of the blue moment

Days are getting shorter but in the design project we need to push forward and maintain the energy for the work.

There are many things in the design process that needs to be realized from sketches to real design. We also need to produce first rendered images of the boat to give people better idea of the concept.

Few fundamental arrangements will require lots of thinking. Just to mention one, cockpit is one of these. My basic idea was of course based of simplicity and safety – narrow sole with a tiller steering. In offshore there is nobody behind the wheel and in harsh conditions I prefer better support and safety of narrow cockpit. That also gives more space below and large volume lazarette under aft deck that would be lost with an open transom, which is needed with large cockpit with the wheel. For some people the wheel is a must, but obviously that won’t work with the same cockpit design with my original idea.

Sometimes it feels that there is too many things to consider and choices to make. Some might say that the solution would be just to design two options. Reality is that in the boat everything is connected to each others and that’s why changing one arrangement causes domino effect of changes – so designing two optional choices is not always the answer.

Basic principle that rises up every day is to keep in mind the right guideline answers to question “why”.

There are also thoughts that needs to be kept in background of mind in a project like this. If you let yourself to think too much about risks or for example challenges of proto boats you will lose visibility of the progress and waste the courage to go on.

After a walk and taking a few shots of beautiful blue moment of November’s fading day I was more focused again. The goal of opportunity to live onboard surrounded by these experiences of nature every day is pushing me forward!

Blue moment in shore of the Baltic Sea

Blue moment of short November's day at waters edge of Baltic Sea

Centreboard sailboat or dériveur intégral – as they say in France – evolution of my thoughts

Here is the shortened description of evolution of my thoughts when determining the hull type of the boat that we are designing – centreboard sailboat, dériveur intégral. All begins of course with defining requirements, because there is not a perfect solution that is suitable for all! So there is not absolutely right or wrong solutions.

With a fin keeled yacht I was rather satisfied with the performance. Even though the boat was only 22 ft, I wasn’t happy with the draft of the hull and vulnerability of the keel and rudder. That prevented many sheltered anchorages and interesting routes. Also the propeller had no protection. On hard during wintertime, the boat was difficult to transport and support.

The obvious solution was a long keeler metal boat. Now the draft was less with solid keel and rudder. But the performance is, how I can say it with diplomatic words to our boat, let me say classical.

The next evolution of my thoughts was a boat with longish fin keel. But a low aspect ratio fin keel is not so effective related of generating lift. Then I considered lifting or pivoting ballasted keel, but the forces that the construction is faced of are high and there is a risk of real troubles.

Then I started to study centreboard yachts that are known in France with name dériveur intégral. As many of us, I have been suspicious about their stability, but then I began to understand what was it all about. AVS (angle of vanishing stability) is probably still the best known and easy to understand value to describe the stability of the vessel. It is simply the tilt angle where the vessel loses its stability when RM (righting moment) falls to zero. Beyond that angle RM becomes negative and causes the vessel to turn upside down. Of course internally ballasted centreboarder has lower AVS and their ability to carry sails when struggling close hauled in hard blow is limited. The boat has higher centre of gravity, which has also a positive effect that makes her easier for the crew, because you are closer of the roll axis of the hull, not in the long arm of pendulum. And combined with above moderate form stability of chined hull, the boat is also more restful to live at anchor. But you can’t have all strengths in a same package!

When I asked our designer Jean-François about the centre of the gravity at a beginning of the design process he explained in the words of one syllable that centreboarder that is made of aluminium has lower centre of gravity than steel boat with full keel.

AVS describes only a static stability situation, but I believe that in real life the dynamic stability of the boat is more important related to the safety in extreme conditions, because the forces involved are never static. The thinking is based on the law of the force and counterforce. When hit by a breaker abeam the underwater body of the hull and its appendices generates counterforce for thrust of the wave in the form of lateral grip. Under the force of the wave the boat with enough lateral resistance sideways starts to tilt. And if the situation gets worse then the boat might invert in the procedure which is described as “tripping over the keel”. Eric Tabarly illustrated the effect in his book “Guide pratique de manoeuvre” (Practical yacht handling).  The boat with long keel has a huge lateral resistance but some designs with short keel might also have enough surface area to produce enough lateral resistance for tripping.

Centreboard boat with centreboard hoisted has less counterforce by lateral resistance of the underwater body and it gives the boat the ability to absorb the power of breaker to sideslip movement maintaining its upright position. And because centre of lateral resistance is well aft the boat turns its bow away of wave crest.

If ever getting inverted despite of what is described above the design of the deck and superstructure has an important meaning of reducing inverted stability. The long and rather narrow cabin trunk and the extended pilothouse with watertight door will make the boat less stable if inverted. Please see the picture below, our boat has a relatively high conical shaped superstructure cross section for a reason. Low volume enclosed cockpit also adds buoyancy aft and helps the boat float higher in an inverted position. These things have an important role in internally ballasted boat that have a lower centre of gravity in inverted position compared to a fin keeler. When the next wave tilts the inverted boat, the centre of buoyancy moves quickly outwards of the centerline and helps highly floating boat to turn back upright again.

Zentralschwert segelboot

For me balancing the boat under sail has always been one of the greatest satisfactions when sailing. Because the water is thousand times denser than the air I have always wondered why balancing of the boat is usually done with sails only. Centreboard yacht will have much more ability in terms of adjusting balance in different conditions. If stern daggerboards are added the weather helm can be reduced even more effectively when close hauled. In running or broad reach conditions the centreboard is hoisted and the centre of the lateral resistance moves aft making the boat very course stabile. The boat flies straight like an arrow, and that is the most valuable feature if you want to sail far destinations surrounded by blue water.