Complex sentence: USS "Ottumwa" (YTB--761) was laid down as a large harbor tug in December 1960; designated 25 April 1961; launched the following month; and completed in October 1961.
Split into simpler sentences: USS "Ottumwa" (YTB--761) was a large harbor tug. Laid down in December 1960; designated 25 April 1961; launched the following month; and completed in October 1961.