Ships with anti ship or anti air missiles mounted on board can obviously stay much farther away. Smaller speedboats with anti aircraft guns mounted on board or rocket launchers have to get close, surround a larger ship. Their tactic is to unexpectedly start shooting at a larger ships vital points all at once, unload, damage while moving and then speed off.
Can a speedboat outrun something like a Brimstone missile, obviously not, just compare the max speed of the boat to the initial-max speed of the missile. A speedboat won't have much of a chance if jets are in the area. If a speedboat is being tracked by a jet it's only chance is for it's countries air defenses to engage the jet first. Ships in the area with SAMs mounted on board are another variable that could perhaps help the speedboats survive.