When you say "Cannon Turrets (35)", please tell me you mean MLA Auto Cannon point defense and not MAC Cannons.
Yes, I think. Edit
I do. Mainly those and several anti-aircraft turrets for Banshees and Seraphs.
Cairo Station Shipyards?Edit
Cairo station was a single SMAC.
Theres also its size, it carries 3 MACs, yet is barely the size of a destroyer?
Answer to MAC question Edit
Cairo Station Shipyards was a placeholder to state it was built orbiting Earth. Also, the Overlord was rather short, but very long, with a single MAC on the nose, and another on the side, on a wing-like appendage. The MACs were a last resort, as it would take out just about any Covenant crusier in a single volley, but it completely drained the ship of all power excluding life support, cryo, and the electricity needed to keep all airlocks closed. It would be completely useless until a repair station could recharge the power. Thus, the MACs were only used once in it's existence.