Does anyone still use signal flags ?
Admiral Lord Nelson is well remembered for his flag signal "England Expects...." hoisted before the battle of Trafalgar, but you might think that by now signal flags have gone the way of the dodo. While it's true that radio, radar, AIS and the mobile phone have caused the use of flags to be much reduced, they have not gone away completely. And where they are still used, they are important.
Maybe you watched a TV programme recently about a company who were undertaking some underwater work in our locality, and who were unhappy that passing vessels were not keeping sufficiently clear of their diver. They had displayed an appropriate warning flag, but evidently hardly anyone new what it meant.
It's true that the use of flags is mostly confined these days to working and commercial vessels, and they are very seldom seen flying on recreational craft. However, recreational craft are expected to comply with the instructions that they give. So lets review the flags that you are most likely to see.
(To be honest, you wont go too far wrong if you assume that most flags and flag combinations are telling you to keep out of the way. There are a couple of exceptions which we can cover towards the end.)
The next is BRAVO, meaning "I am taking in or discharging or carrying dangerous goods." Again you should stay well clear... but this time it's for your safety.
This combination (occasionally seen in Portsmouth harbour) means 'Pass wide and slow'.
And finally this one means 'keep well away', usually because there is some underwater work going on. 
This one, OSCAR, means 'I have a man overboard'. You might see it on a floating danbuoy that has been put in the water to mark the last known position of the MOB. [If you have such a danbuoy, please ensure the flag is furled while the buoy is stowed. You dont really want to sail around accidentally telling everyone that you have a man overboard. We've seen it happen and it causes unnecessary alarm].
