Just a thought I had whilst gazing at bonzer pics on the web.
If a vortex twisted off the fins and was sustained in the concave, running out the back, wouldn’t that help hold a turn, as the faster vortex water would present as “harder” ?
I remember reading in the tubercle article that the tubercles were vortex generators, and that the vortices “injected momentum into the water flow” which kept it attached to the top of the wing better…
It was the five fin model that really got me thinking, in particular, one had little concaves that started between the 2 side fins and ran off the rail, I can picture a little water twister just spinning in that little trough…Then it occurred those flat little ellipse sectioned fins look like wingtips, which are also known to induce a vortex now and again…
Or should I get my tap water tested?