Being the person who put the Kim keels on his Eco 6 let me contribute some thoughts. When I ordered the plans for the Eco 6 and began building I accepted that the design called for the daggerboard in one hull, and I also knew this would provide the best windward performance. But while I was building the hulls and joining them together I didn’t think too much about the daggerboard, but I did think a little about keel options. At the same time I was building my boat an Eco 6 was being built in Australia which had drop down keels,(centerboards?) on the inside of the hulls, but as I looked at photos of that build I thought that it seemed a complex structure and would add a lot of weight. I did think about the option of low aspect keels under the hulls, such as on the Wharram Tiki catamarans.

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As I began assembling the hulls to the bridgedeck and forming the cabin structure I realised more and more that the daggerboard case as designed was going to really impact on the interior and make access to the port hull difficult, and I was starting to feel a bit lazy about building the daggerboard and case. About this time Rien in Australia decided that his exterior drop down keels were not working, more because of the weight issue combined with what was already a heavy build, and he needed another option, and that is when Bernd came up with the kim keel design as a solution for Rien and also gave me the drawings. I decided to at least give the kim keels a try and see how they worked because they would be a lot more simple to construct than any of the other options. If they did not work out then I could always retrofit a daggerboard.

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Construction and fitting of the kim keels was very quick and simple and used up about $20 worth of timber which I purchased specifically for that job, and of course a little bit of epoxy product and glass cloth which I already had in abundance. ??

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So as to the sailing performance. As already stated in other posts I am very happy with the way my little catamaran goes to windward. We have a long narrow harbour with up to a one knot tidal flow, and sometimes more at the entrance. I have now many times tacked my way either up or down the harbour against the tidal flow and to me in that situation the boat seems to go to windward just fine. Keeping in mind that it is a cruising yacht, but for cruising needs there is nothing wrong with the windward performance of the kim keels. I do also have good sails and pay attention to sail trim so this will also contribute to the windward performance of the boat. In truth I think there are three factors which contribute to the boats leeway resistance; firstly the deep almost vertical forefoot which extends aft from the bow for quite a distance, the kim keels, and lastly the deep high aspect rudder foils.

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So in summary, the kim keels were quick and easy to construct and fit to the hulls, they add almost no weight to the structure, they do not intrude into the vessels interior, they do not protrude below the hull so hull draft is only 200mm. For a coastal cruising catamaran which needs to be able to sail to windward at times the windward performance of my Eco 6 is perfectly acceptable and certainly equals the windward performance of other cruising yachts I have owned, so happily I see no need to retrofit a daggerboard.

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Cheers,

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David

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