Complex sentence: On 11 June 1929 a detachment of marines was sent on "Kortenaer" to Curaçao after Venezuelan rebels had raided Fort Amsterdam in Willemstad on 8 June.
Split into simpler sentences: On 11 June 1929 a detachment of marines was ship on the "Kortenaer". The ship was sent to Curaçao after Venezuelan rebels had raided "Fort Amsterdam" in Willemstad on 8 June.