Here we can see the midships area of HMS Hood:
The hull form in this area, was protected by the thickest belt armour - of up to 12 inches. The idea was a simple one: important machinery (such as the boilers and engines), were enclosed in the thickest belt armour, so that warships like Hood, could take punishment under fire, and still maintain a manoeuvrable gun platform (aka the ability to fire their primary naval guns). Unfortunately, Hood's machinery spaces were considerably long (about 391 feet, 45.5 percent of her length), and she had been designed in a time, when plunging shell fire (which would penetrate the deck), had not really been considered. Hence, the midships deck armour was way too thin, and what armour there was (of up to 3 inches thick), was spread over too small an area! Such short comings, were not known to her sailors - who believed her to be the greatest warship in the Navy, and she was :) This view also best showcases Hood's secondary armament - her twelve 5.5 inch naval guns. These were designed to engage surface targets only, such as destroyers - which could have easily launched torpedoes at her. These guns, would also have supported the primary 15 inch naval guns (when in range).
Here we can see the details of the midships area of HMS Hood:
Of particular interest are: i) The eight barrelled 2 pounder anti-aircraft pom poms gun. ii) The 4 inch high angle anti-aircraft gun. iii) One of the secondary armament 5.5 inch naval guns (with it's protective shield). iv) The smaller crane derricks, which were helpful for lifting both ammunition, and smaller boats. v) The torpedo look out control towers. Which I believe, would issue just one command: take evasive action! vi) Venting for the boiler rooms (located at the base of the funnels, just under various life rafts). vii) The smokestacks themselves, which vented waste gases and heat, from Hood's boiler rooms. There's an unproven theory, that the shell that sunk HMS Hood, may very well have penetrated one of these, and detonated the oil fuel (inside her boiler rooms).