Wednesday, June 27, 2007

Yacht Design

Ok, so after a few days in SL, I saw that there was active sailing going on there... As I am a yacht designer in real life, hey! maybe I can start designing boats for my fellow residents, I thought. Well, there are already quite a few designs out there, the most common of which seems to be the Tako, a dinghy that is raced regularly. The scripts behind it are even available on the lsl wiki !

I tried my hand at modelling a boat in world, but I just don't understand how it is done. The editor is extremely limited. All I could manage was a triangular box...

Anyway, it doesn't matter because the shape has absolutely no influence on the performance. Everything is done is the script. The script I saw is not based entirely on physics, It seems to try and approximate the behaviour a boat, and I don't know how realistic it is as I never sailed one. For example the leeway angle seems to be based only on the angle of the wind, the strength of the wind and the heel angle. This is not true as boatspeed, sail angle of attack and sail angle relative to the boat all have to be taken into account. As I understand this script, if you are on a beam reach and sheet the sail in hard, the boat won't drift sideways like it does in real life, with both the sail and keel stalled.

So my goal is to develop a boat that has a more real life like behaviour, by using a realistic GZ curve, lift and drag coefficient curves for both the sail and underwatershape and solving the resulting equations 3 dimensionnally for the required variables (speed, leeway, heel, etc...)

It's a daunting task, but I think that It can be done. After that, I just need a boat to put this script in :)

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