DelftShip – first impressions

So I got this iMac with the dual core capability plus the virtual machine environment to run both OS X and Windows on the same machine. It runs really well! The next step was to get the free version of DelftShip, a nav arch software that can do a lot of things. Not everything but quite a few tricks. Of course it took a while – as one of their forums says in the footer: ‘if something does not work well on the first try, have a beer’.

So here is a body plan from my paper version:


And a lines plan. Not clear yet what the two bodies mean


Finally a curvature plot that indicates a vew weak spots (the blueish areas inside red – this means no compound curvature but more like a saddle configuration.


But what I really wanted are hydrostatics etc. The model predicts a displacement of 1.5 tons. I had done two planimeter exercises (sectional areas plus Simpson’s rule) before with results between 1.3 and 2.1 tons. Something is still a bit off. Metacentric height is 1.8m above base. Total hull area is about 26 m^2. If I use 1/2″ plywood, the hull will come to about 300 kg plus say another 150 kg for keel, frames and rigging (hollow spars). So I will need about 1 ton in water ballast, close to the floor. This will put the CG to about .4 m above base, leaving a nice 1.3 m or so of MG for a stiff flyer.

 And Delftship gives me a resistance curve as well:


Not quite clear what that will mean. At 5 knots the Froude number is already at .34 or so which means that we either plane or won’t get far beyond that speed. We’ll find out, I guesss.

That’s it for another late night.

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