HMS Sirius, colony artillery, and defensive planning

HMS Sirius can appear as either a ten-gun vessel or a post ship in descriptions of the First Fleet. Her known battery was small, but contemporary discussion suggests that additional guns may have accompanied the expedition. Those weapons might have strengthened the convoy, though the fleet's route was deliberately chosen to avoid confrontation. A second possibility is that they were stowed for shore defenses once the colony was established. That explanation fits the decision to embark Marines, while also raising the practical question of why heavy guns would be mounted high enough to worsen topweight if their intended destination was a land fortification.