Presumably the Dutch pronunciation sounds somewhat like the English ‘skate’?

Although always willing to defend a Dutch CANOE, I’m afraid that in this case it is a bit of a stretch. The glide -ui- is difficult to render in English. I would expect it to come out more like an -au- or -oo- in English. I’m thinking of the pronunciation of Dutch names like ‘de Bruin’ and such.

Maybe schuit is the origin of skate, but I don’t think the pronunciation supports that theory.

The Afrikaans pronunciation of skuit is nearer to the English, sounding something like uh-i.  Say skuit in Afrikaans quickly and you get an approximation of skate.

I too am skeptical of the sexual origin story. An association with the sea is enough to explain it--the choice of fish may be pretty much random (e.g., the US equivalent derogatory term for a sailor is squid).

I haven’t seen any actual evidence of a sexual origin--claims at various wiki-driven websites aside. I’m away from my slang resources at the moment, but when I get the chance I’ll comb through them and see what they say about the term.

Good point Eliza. I was thinking of course of ‘Algemeen Beschaafd Nederlands’ (“Proper Dutch”), but there are so many local variants. E.g. in Amsterdam dialect ‘schuit’ sounds a bit like ‘skaat’. One may doubt that the sailors back then were speaking ABN.