[jonex]

It's clearly not properly designed to be for swedish, this is noted in the reply, apart from some letters being off, it lacks åäö. But it's still not clear why they would use "u-boat" for u. While apparently correct english (never heard it), it being Swedish ubåt seems higher likelihood to me.

I'm wondering if they might have combined mixed two designs, as a lot of the letters works in both. Maybe they looked at two pictures and didn't realise one was for another language? It seems possible to me that they'd design the ball based on product pictures, and those are often not showing all angles of a product.

Don't think it's easy to say one answer or

[HideousKojima]

U-boat nowadays is used almost exclusively for WW2 era German submarines

[thaumasiotes]

That's not a "nowadays" thing. That has always been the meaning of U-boat; it was an explicit propaganda goal to use different words for German submarines and American ones.