What happens if a fleet involved in a convoy is attacked?
The convoy fails only if the fleet performing the convoy is dislodged. Sometimes, in order to improve the odds that an army gets to it’s destination, multiple fleets may attempt to convoy an army. (i.e. Army in Belgium moves to London. Fleet in the English Channel convoys army from Belgium to London. Fleet in the North Sea convoys army from Belgium to London. Convoy will succeed unless both fleets are dislodged.