Aboard ship, in which directions must aircraft engines be secured to prevent shifting?

Aircraft engines must be secured in all directions—forward, port, starboard, and aft—to ensure their stability during transit on a ship. Securing engines in these four directions helps to mitigate any movement caused by ship motion, such as rolling or pitching, as well as forces experienced during loading and unloading.

Failure to secure engines adequately in all directions could lead to potential damage to the engines themselves, their mountings, or surrounding equipment, and pose safety risks to personnel aboard. By ensuring that engines are secured forwards and backwards (fwd and aft), as well as side to side (port and starboard), the ship's crew can maintain safe and efficient operations.

The other options imply limiting the securing process to just a couple of directions, which would not provide adequate protection against the various movements that may occur on a ship.