Je was op zoek naar: synchronisation (Engels - Xhosa)

the greatest movement develops when there is synchronisation.
ubukhulu bokushenxisa ukwenzeka xa apho unokwenza kwenzeke ngaxesha-nye.

when the period of encounter approaches synchronisation with the period of roll or pitch, the ship's motion will be violent.
xa ithuba elibalelweyo lokusondeza ukwenza kwenzeke ngaxesha-nye ngokwexesha lokuqengqeleka okanya ugxumeko, inqanawa enetshukumo inganobundlobongela.

whatever sea is running you sometimes have to break the synchronisation of the waves and the boat's roll by altering the boat's speed or its course.
nokuba yintoni ebalekwa lulwandle, wena ngamanye amaxesha kufuneka wophule amaza awenzeka ngexesha linye kunye nomqulu wesikhephe ngokulungisa isantya sesekhephe okanye indlela yaso.