(In this post we share some thoughts on leeboards from multihull designer Bernd Kohler. He uses his “Little Tri“ design for illustration purposes.)

Little Trimaran Leeboard – Some Thoughts
by Bernd Kohler

Here is one approach to the discussions found in the “Hybrid leeboards” article. I was very pleased to read that article. What’s interesting is my over complication of some ideas. But it dos not matter; it’s more important to bring the “outside boards” idea up again.

I am Dutch, so for me, it is a common thing. Many Dutch boats have had them for generations. Another one who used them is my favorite American designer Phillip Bolger. I also note Jim Michalak’s boat designs.

On my old Butterfly catamaran (from 1986) I used these “inside” outside boards. But I wanted to share pictures here of the “Little Tri” that is owned by Hans, who has a good eye for good photos. He is sailing his boat in Holland.

As in most cases, there is nothing new under the sun. Dutch fisherman used slender (dagger) lee boards already for there sea going boats since the 16th century. The boat type is known as Hoogaars…

This historical photo of a vishermans race of hoogaars was made in 1928. * Some find them un esthetic, but beauty is in the eye of the beholder as always.

There are many points which speak for “outside boards.” Why I call them so? I used them not on the lee
side but also on the windward side on some of my designs.

Modern materials make this possible. They are as effective as any leeway preventers inside or outside of a hull. It is more a matter of correct design. The argument that they are not effective is pure nonsense. Watch the photo from a “Little Tri”, for example …

The boat sails clearly to windward. Observe the straight trail on the water. Not a bit of drift to leewards. Almost no water disturbing from the board. The board case is just shown on the windward side.

There merits are obvious. Need no space on the inside of the boat. Very safe too … if grounded hard and there is damage it is outside of the hull. A leeboard is easy to build and easy to handle, especially when only one board is used, as in the case of the boat above.

The notion that they ventilate, and other hydrodynamic arguments used against them, are nonsense when leeboards are correctly designed. Watch the video below. Any ventilation? As I am sailing my Little Tri you can see the board the whole time in action…

From minute 1:08 till 2:26 the boat sails at about 6 knots. There was not a lot of wind at this day by the way (about 6 knots).

What’s important is that the board has a good profile and is set in the correct way. For small boats a bungee or
soft wedge is sufficient to hold them down.

* The “Historical Society Arnemuiden” granted us permission to use the above historical picture

Here are some photos from a week long journey Hans made this summer. I like his photos. They show typical Dutch land and seascapes.

Shortening a lateen sail is not so easy. His solution is to brail the sail the old fashion
way…

A restful day…

On one of the many channels we have in the Netherlands…

On the Waddenzee …

In good company…