In August 1914 just one week after the outbreak of war, Harold Ozanne was posted to HMS Cressy a 15 year old cruiser which had recently been taken out of reserve. Her crew had been thrown together at short notice and was comprised of older reservists and young Boy Sailors, some only 14 years old, including a whole class of cadets from Dartmouth Naval College.
Cressy and her sister ships Aboukir and Hogue were sent to patrol the North Sea off the Netherlands coast. Many senior naval officers pointed out the danger of leaving slow and obsolete warships exposed to the threat of German submarines, and some nick-named the patrol the 'Live Bait Squadron'. But others dismissed the threat, regarding submarines as toys and unproven in battle.
But these three cruisers were soon to be involved in one of the worst naval disasters of the War.
On 22 September they were attacked by a German U-boat. The Aboukir was torpedoed first and sank within 35 minutes. Hogue and Cressy returned to pick up survivors. Whilst stopped in water Hogue was hit by two torpedoes and also began to sink. Cressy then realised the danger and started to move away from the scene, but she was hit and sank within 30 minutes.
Dutch fishing boats rescued 837 men from the sea, including Harold Ozanne, but 1397 men and boys were lost.
Overnight this event changed the world's perception of submarines, put a cloud over the future of the battleship and greatly damaged the reputation of the Royal Navy which until this point had been regarded as almost invincible.