At the age of sixteen he entered the navy, and saw a good deal of dangerous service in the extirpation of the West Indian pirates.

The exciting experience was exactly to the liking of young Winslow, whose life more than once was placed in great peril.
After an extended cruise in the Pacific, he returned east in 1833, and was promoted to past midshipman.

His service was of an unimportant character for a number of years, the rank of lieutenant coming to him in 1839.

His conduct was so gallant in the war with Mexico that he was publicly complimented by Commodore Matthew C.Perry, a younger brother of the Lake Erie hero, and given the choice of vessels belonging to the fleet.
A curious incident is mentioned by his biographer.

He went with the division which set out to capture Tampico, but the city surrendered without a fight upon the approach of the boats.