Why maximum subdivision is not a free upgrade

Should the design maximize barbettes and bulkheads for protection?

Not automatically; added protection helps survivability but can reduce range and create stability tradeoffs.

More subdivision and barbette protection can improve survivability, but the design penalties still matter. Maximum bulkheads consume capacity and can reduce the range available for a globally deployed warship. Added protective weight may also interact with stability rather than functioning as a cost-free upgrade. A balanced level of subdivision preserves endurance while still making the ship difficult to disable.