And back to catamaran

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After some careful consideration (and a few glasses of wine) I decided to go back to my original catamaran design. The main reason for considering the box keel was improved living space and standing-height inside the vessel. My initial catamaran design had quite high floaters, roughly 50 cm. This meant I also had a 50 cm tunnel traversing the vessel. I decided to lower the height of the floaters to only 20 cm, making the tunnel less pronounced and thus increasing inside space. The designed draft is about 10 cm, so 20 cm floaters still provides ample safety margin.

Pictures below show the two catamaran designs side-by-side. The second design clearly shows the less pronounced tunnel in the middle. The pointy bows help increase length over water (LOA), which helps course stability and efficiency.

Other arguments for a catamaran design:

  • Good stability, especially in calm, inland waters
  • Good course stability: the smaller contact area with the water means a better width to length ratio. The box keel, or flat bottom, would have a ratio of around L=3.5 / W=2 = 1.75. The catamaran, having 60 cm floaters, would result to L=3.5 / W=(.60 × 2) = 2.9
  • More storage in the floaters for batteries etc
  • Smaller surface contact area means more efficiency; more speed from the same energy
  • Looks cooler imho


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