Perhaps it is a patent or other
Posted by: Kocho on Apr-12-12 5:00 PM (EST)
issue, who knows. I did not come-up with the idea of the bullet (Red or whatever the ski maker is) did some time back (at least for this application) and they sell "kits" to retrofit skis with bulleted drains. But mine works well enough and indeed is simple to make. The tric is that the size, shape, and position matter a lot and being able to quickly see the effect real time (by repositioning the bullet or changing to a slightly different shape) was interesting and allowed me to pick a shape, size, and a position that worked better than others. Still, I have no idea how closely that corresponds to in-water conditions and perhaps there something else might work better. There was an article at surfski.info with a pressure model of a scupper with and without a bullet, so one can visualize what is going on and why suction goes up and resistance - down.