Interview With Bernd Kohler

by Bernd Kohler - The Netherlands

When did you become a boat designer and what was your first real design?

Making things and designing is a lifetime addiction. I use the therm addiction on purpose. My first design? An ice boat. I designed the thing when I was 12 years old and with the means we had in East Germany, which was not much. This was 1952! The “hull” was from planks made in a T configuration. Skates? The old fashioned ones which had to be fastened with dump screws to normal shoes. Sail, a sprit sail made from a berth sheet. A lot of fun and a sensation on our local lake. OK getting serious.

The first serious design was a 4,2m long dinghy designed and built in Switzerland 1965. Next, 1968 was a single chine cutter, our “Pelican“. 8,5m long, 2,8 m width, relative short keel and a transom hung rudder. The rig was a kutter mast head rig. The jib and the mainsail where handled with self made furlers. I developed for the main sail a vertical furling system on a yackstay. It was the first sea going boat with such a system. The boat was very seaworthy and the accommodation was perfect for our goal. The boat was made from Gaboon plywood and larch. Gluing was done with Recorcinol glue. I worked professionally, by the way, with Epoxy (Araldid).

The boat was a sensation on the Lake of Zurich. We sailed with the boat partly down the Rhine. It was in March 1969 in the high water. The locks after Basel and the Lorelei were not designed for such a small boat so the boat was transported on a barge to Emmerich. And in this way, we came to the Netherlands. We where living on the boat for almost three years. Visited Belgium, the UK, Germany, Denmark etc. The “Pelican“ was in my view my first serious design. We sold the boat and became landlubbers. Life goes on. Flying was for a time my thing. I had got my Ppl lizense in Switzerland some years before. I worked in the aircraft industry, partly for Fokker, until the Dutch government let go the company broke for political reasons.

By the way, Fokker was the first company which used Epoxy. The Aluminum wings from the F 27 where glued together with Epoxy. The F 27 was a very successful small passenger aircraft and is still flying in some countries in Africa.

The first aircraft were glued together. Fokker was no exception. The first passenger aircraft from Fokker the FII was no exception. The most famous from this line was the Fokker F VIIIa with 3 engines. Ford built the aircraft under license in the USA from Aluminum.

In 1966, we restored an old wooden “Pirat“ racing dinghy. We covered the hull with fibreglass and Epoxy (Araldit). Because of the high costs of Araldit, people used Polyester with no great success. Twenty years later the Pirat was still sailing.

PENGUIN on the Zurich lake

Which designer(s) had the greatest influence on you?

This is a very difficult question because there are many. It starts of course with monohull designers like like Manfred Curry, Herreshoff and Bolker. For the multihulls, Peter Spronk, Hugo Myers and Dick Newick. But the biggest influence I see for my work came from Woody Brown. His asymmetrical “Manu Kai“ was built built in 1957 in Hawaii. Length 40 ft, beam 13ft and an empty weight of 2000 lbs (908 kg). Sail area 500 sq ft. Woody used his light aircraft experience. The boat is a plywood construction. On a good day the boat was going 28 knots.

How many boat designs have you drawn in total?

I started designing boats seriously relatively late. My first multihull design is the SC 435. I designed and we built the boat in 1979. In total I designed 38 multihulls, 12 monohulls and two wing in ground effect crafts. This includes also the multihulls which where custom designs. I designed also an Aluminum catamaran of 48ft.

Many of my designs you can find on my web page www.ikarus342000.com/CATpage.htm and www.duckworksbbs.com/plans/kohler/ and also some of my custom designs ikarus342000.com/CUSTOM.htm. The DUO 900 started as an custom design like this houseboat www.ikarus342000.com/houseboat.htm and ikarus342000.com/DUO900page.htm. One of my wing in ground effect crafts is shown here.

www.ikarus342000.com/Skim24.htm and skimmerii.weebly.com . The customer made some not so successful changes and he reverted to the original design. I know the craft will be then be okay.

My most famous design is of course the Albatros named after the sponsor ZEEMAN. Here a photo from the craft on its way around the world.

Which of your designs is your best seller, and which is your personal favorite?

For the small ones, the SC 435. I stopped counting as I reached 600. From the bigger ones the KD 860 is an absolute runner and is going on. From the parallel cats, I sold about 480 plans from the DUO 425. From the newer designs the DUO 480 C sells also very well. I do not have a lot of photos of just the DUO 480 C. The photo shown is a DUO 480 C from New Zealand

My personal favorite is the “PELICAN“. She was part of our lives for 11 years through any weather and party. We built the boat in 1,5 years between regular work. From the power catamarans is the ECO 5.5 is my most successful design with the most sold plans.

SC 435 in Finland

SC 435 Ijsland

DUO 480 C in New Zealand

KD 860 Australia

ECO 5 power cat on the Mississippi

Little Tri is one of my favorites. It is a fantastic sailor, can be build for about US $ 1000, – and can be transported on a roof rack of a small car.

Do you have a design philosophy – certain themes or principles your adhere to?

I speak here only to the amateur builder fraternity. My slogan, which I had some time ago on my website, in line with the slogan of Che Guevara “Power to the people“, is still valid.

We have now so many different construction systems. Most of them in my view are not advisable for amateur construction. So I will, also in the future, design in the Plywood/Glass fiber/Epoxy composite system. Any handy person can build a high quality boat using this system. Most persons will have the tools to build the boat already in their workshop. I am afraid that vacuum pumps, vacuum regulator, or special necessary valves will be not in the arsenal and will cost too much for a single project. The quality of the work can be checked by the builder, which for some composites is not possible. A good built boat with this system is almost maintenance free. Cost wise, nothing can compete with this system. Any other system, like sandwich construction (foam, honeycomb, carbon) is a vacuum or infusion technique about 7 times more expensive. By the way, look at the newest racing monohulls. The are more or less sharpies with rounded off chine. I will also draw in the future asymmetrical hulls for catamarans, so that no keels or dagger/center boards are needed to sail well to windward. As long as you keep them light, they as good as any hull shape or better (for instance, no yaw in a diagonal sea). By the way, I advice you to read my FAQ www.ikarus342000.com/FAQ.htm where I explain these thematics a bit more.

I give a lot of thoughts to the practicality of my designs. Inside parts like the top of the kitchen, benches, berths are part of the structure of the boat. This keeps them light and in the end saves work.

I will stay with the anti vortex panels (winglets, chine runners). Look at the latest aircraft like the Boeing 737 MAX. They worked perfectly on our PELICAN (37 ft long boat with 2 ft draft). We went places nobody could reach. See ikarus342000.com/PELICANpage.htm

Look at the two relevant articles from this page www.ikarus342000.com/Looseends.htm. It is possible to better the shape to be even more efficient. Just.

PELICAN, Los Nietos Spain 1990

PELICAN at Amsterdam 1988, designing the ZEEMAN

What key tips would you give to builders of your designs?

Make a choice and take the next smaller model! Because it is not just the two plywood panels and a bit more paint needed for a bigger boat, but the costs for a bigger rig and sails, ground tackle, engine, mooring, trailer etc.

Try do avoid renting a workshop, when you have to do it, look for something near your home. Experience shows that this is the biggest hindrance and many projects were never finished for this reason.

I have no design where the sitting height is under 940mm. I try for standing height in the kitchen and the bathroom. In the saloon you sit or go outside so standing height is not necessary. But sailing to windward can be your life safer. From about wind force 3 my cats sails on the wind, because through the speed of the boat the apparent wind shifts forward and the boat sails on the wind, but only when the boat is low enough, otherwise the leeway is too big.

Most production catamarans will not sail to windward anymore when the sails are shortened as the projected side surface of the boat is bigger than the sail area. This is the reason why they have relative big engines. These boats are in Principe motor sailors.

My cats have at least a length to beam ratio of 1:2 for a good stability. I know already this collides with the road regulations of some countries (2,44m). But I do not design for the road but for sailing on the water in a safe boat.

You want to sail in the tropical paradises of the worlld like Tahiti, or wherever? OK, rent a big boat for your holiday and build yourself a small one for at home. This will be cheaper in the long run.

What do you have on the drawing board now?

I have a lot of ideas for new designs but only sketches right now. So what will come next, no idea.

If I had the time and money, I would like to build this craft.

ikarus342000.com




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