Know more exactly as "Sid Meyer's Pirates!".
This game was one of the best of it's generation, with a deepth and replay value far beyond so many productions.
It was ported on most 80's standards : C64 (looks quite a lot like the amstrad CPC version), Atari ST, Amiga, PC and more.
Some new updated versions were made too : "Pirates! gold" (with VGA colours on PC) and a modern PC "Sid Meyer's Pirates!" 3D version in 2004.
The Amstrad CPC port was released in 1988.
It is notable for being one of the rare 6128 specific game : only disk version and 128Ko Ram were supported.
In theory, 464 (+ disk drive) and 664 with Extra Ram upgrade should work. (maybe not ?)
It included a lot of Graphics (Mode 0) and musics.
Games sequences, possibilities and mechanics were varied.
Despite it's ultimate awesomness, the Amstrad CPC port was a bit slow and Graphics could have been a bit better...