Final answer:
When emplacing a howitzer, spades should be dug up to 8 diameters wide and 15 diameters deep according to newer recommendations, providing more substantial support and stability for the artillery piece.
Step-by-step explanation:
When emplacing a howitzer, depth considerations for digging spades come from practical field engineering principles. Traditionally, a "rule of thumb" would suggest digging 5 diameters wide side-to-side and 7-8 diameters deep. However, recent work advocates for more extensive preparations, recommending digging spades up to 8 diameters side-to-side and 15 diameters deep for adequate support and operation of the howitzer.
This method ensures that the howitzer is securely emplaced, minimizing recoil and ensuring stability during operations. Comparably, while not directly related to artillery, the ambition for deep-earth projects like dense thermal collection grids is considered unrealistic, as the deepest mine is less than 4 km deep, which serves to highlight the practical engineering limits within our current technological capabilities.