Marines float and tread water during their swim qualification in the Ramer Hall pool at The Basic School on Feb. 4. Marines are able to tread water or use their blouse or trousers as a floatation device. - Marines float and tread water during their swim qualification in the Ramer Hall pool at The Basic School on Feb. 4. Marines are able to tread water or use their blouse or trousers as a floatation device.