All vessels with a Colombian registration certificate must have a Colombian captain, officers and no less than 80% of remaining crew must be Colombian nationals. 
"Article 99. Additional requirements for Colombian-registered ships. In ships with Colombian registration, the Captain, the Officers and at least eighty percent (80%) of the rest of the crew, must be Colombian. Spanish must be used in the verbal and written command and service orders of the ship and in the annotations, books or required documents. The General Maritime and Port Directorate will authorize shipowners to hire foreign personnel, when in the country they have not trained or qualified in sufficient numbers."
(Decree no. 2324 Reorganising the General Direction of Maritime and Port Affairs (18 September 1984), last amended by Decree no. 2106 of 2019, Article 99 [google translation])
Decree no. 2324 Reorganising the General Direction of Maritime and Port Affairs (18 September 1984), last amended by Decree no. 2106 of 2019, Article 99
[<a href="http://www.suin-juriscol.gov.co/viewDocument.asp?id=1436346">Decree</a>]