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IOM Design

Prototype finbox for Noux

Although we've already built a number of finboxes, I've forgotten to publish the plan - so here it is. As the Noux Mk2 is still somewhat of a prototype this finbox has a long 27.5 x 5 mm slot for the mast which will allow optimisation of the best mast position and rake angle during testing. So as not to carry a whole lot of extra water in the boat we made the mast-box narrow, 5mm, which means that the lower end of the mast needs to be an aluminium extrusion of 5mm width... A future Noux Mk3 might again have a more traditional mastbox for a round mast when we have found the optimal position.

4 replies on “Prototype finbox for Noux”

hi there i was wandering this fin box i have study it but i am bit puzzeled as to the slot for the mast why it is oblong instead of round to fit the mast, i am novice and i have built a hull it is not the noux design but a topika and i am stuch as to how to make the fin box

Hi Alexander,

When designing or building a new boat there is always a bit of uncertainty as to where the optimal position of the fin with relation to the mast is. The Sails ETC boats use a fixed mast position, but the fin position can be adjusted forward and aft by cutting the fin to suit the finbox in different ways.

With the Noux we did it the other way around: the fin is fixed, and the mast can be moved forward and aft by about +/- 10 mm. We're hoping that will give us enough room to experiment and find out the best tune for each rig and wind condition. We made the hole rectangular, 5 mm wide, so that the amount of ballast water that the hole carries with it would be a bit reduced from the amount it would be if the hole would be oval and 12mm wide. To fit the mast to the hole we're fitting a piece of 10x5 mm aluminium to the end of the mast. At least that's the plan right now.

Anders

Hello Anders, I’m Luciano from Milan , I’m building boats Noux-2 following your project (NOUX 2 Preliminary layout plan 2006 Feb 15 Anders Wallin). I have a question about fin-bulb: could you give me the exact position where the C.G. of the bulb has to be positioned on the fin.
Many tanks,
Regards,
Luciano