to wil and his companions , their trip coincided with a water festival and they became witness to a column of heavily festooned boats each one joined to each other by a platted rope , and each boat propelled along the narrow waterway by brightly costumed oarsmen standing behind each other with their oar tucked in behind one foot , it moving in unison with all oarsmen , and they paddling to the beat of a drummer standing on the bow .