At the very top of the Castle is the Ramparts and accessed through a small door in the attic.
This is an area that encompasses the structure and would have given views over the land of Hunterston and is also the defensive part of the castle.
There would have been a soldier patrolling the ramaprts of all times day and night looking out for any threat to the castle and watching over those passing nearby and would have been able to shout out warning to other soldiers of an impending attack.
This stone structure has various holes in it and known as Crenels and Merlons of which there are seven of them. The cut out portions are called Crenels and the solid portions between the crenels are called Merlons.
While being attacked by an enemy the soldier could take cover behind the merlons and when attacking those below they are protected by the part of the wall below the crenel so only the upper part of the body is exposed during the shot. The merlons also protected the soldiers from arrows and other objects that might be launched from most angles other than straight on.
Due to the small size of the castle and ramparts only small bow and arrows or guns would have used but it was still adequate to protect the inhabitants.