So Joseph Zisa is either refusing to share CAD files of his v29 whistle or doesn't have those.
So I decided to make my own based on his.

This one is created from scratch, I only used general idea of Joseph Zisa for that design.
Idea's good.

Shape Is a bit different and there is no internal ribs so you can print it much faster without loosing any function (probably shouldn't print this without infill).
And much cheaper, because thermoplastic can be expensive.
And it can be much lighter, thus allowing it to easier staying afloat if printed with less infill.
It doesn't need all that extra weight from redundant ribs v29 have.

The sources are there:
https://cad.onshape.com/documents/127002769eb5c2412870432a/w/84e3ee8687bc0f8d1c3acb2c/e/6e75b4f3ba9b11e85a305dd4

Do not use it in enclosed room.
It is loud.