Why did Surcouf need several minutes before firing?

Why did Surcouf need several minutes on the surface before firing?

The crew had to remove gun waterproofing, unlock and enter the turrets, dry and check equipment, and prepare the weapons.

The guns had to be unplugged and their waterproof protection removed after surfacing. Crews then needed to unlock and enter the turrets, clean and dry equipment, and check that everything was ready. This preparation left the submarine exposed before its heavy guns could contribute. Launching the reconnaissance aircraft could add another task to the same surface interval.