Served my time on some 12 passenger ships (more than enough for me ugh!) I was once asked what the rondel was on top of the for'd wooden topmast and what was it called, told her it was called a truck and it prevents rain and seawater getting into the top of the mast thus stopping it splitting. She said NO! tell me what it's really for, so I told her it was still called a truck, but at night we filled it with seagull **** and wheeled it away. Thus ended my career on passenger vessels