Whats the difference between nautical flags R and M?
Wikipedia has the flags incorrect. International code flag “M” means “Vessel stopped, making no way”. This means that the vessel is drifting. To be “underway” means the vessel is not made fast to shore, anchored, or aground; to be “making-way” means that the vessel is moving through the water. International code flag “R” is a procedure flag signal meaning that your message has been received.