Concave venturi design

Has there ever been a concave (Negative scoop) venturi design in a surfski ? Advantages: Smooth hull profile, nothing to break. Disadvantages: Doesn't drain quite as efficiently ? More labor intensive to manufacture ?

They have invented stuff much better than that, an opening bailer? Smooth hull, zero drag and then drains very fast when open.

Not sure you want a ventury with constant drag 100% of the time, even when empty?

I believe kai waa (makers of the amazing vega surfski) make their outrigger canoe venturis that way. The Venturi cover is flat and the hull is recessed behind and under it. I am not sure why they do not do that on their skis but suspect it might have to do with the need to get center of gravity lower in a ski for balance. To do that the floor of the footwell and the outer hull have to be quite close together. With an outrigger balance seems to be not such a critical issue.

No, If that system were so good they would do it on their skis, and guess what, they don't?

An outrigger has a drop of water to get rid of in the footwell so that system works just fine as it did with skis that had no adjustable footplate. Been there done that!

However a modern ski has huge amounts of water to empty out so a much more efficient system is needed. This involves much more drag to suck much more water out as fast as possible, but with the option of reducing that drag to Zero once empty.

Ranga, you're right about that (bailers). I was interested more from a historic perspective before bailers were the norm.