On 12 February 1873 Prat was promoted to Lieutenant Commander. On 05 May 1873 he married Carmela Carvajal. They had three children: Carmela de la Concepción, Blanca Estela, and Arturo Héctor.

He remained as Acting Commanding Officer of the corvette until June 1873, when Commander Luis Alfredo Lynch reassumed his position, while he continued as Executive Officer. On 24 May 1875, while in Valparaiso with the "Esmeralda", one of the worst storms in the history of the city hit Valparaiso, a port whose structure in those days had nothing to do with what it is today.

The ship was buoy fast, and as the weather seemed to be good, nobody expected that such a change would take place in so few hours. Both senior officers were on shore: Lynch as an everyday action, and Prat on sick leave.

On the night of 23 - 24 May, the slight North wind started to gain speed and became a storm. When daylight came, Valparaiso was in a turmoil, and the angry waves bursted against the shore, while the wind shaked the fragile vessels as if they were light and precarious feathers. When the waves acquired a gigantic size going across the decks where the people could hardly walk, with a wind that was completely out of control, the steamship "Valdivia" was pushed against the corvette "Esmeralda", cutting her chain, tearing her bowsprit and foremast. In the face of such emergency, the old corvette went adrift and broached impacting the "Maipú", her comrade from the war against Spain, and currently transformed into a pontoon.

It was a hard moment when Lynch arrived on board, after he had been hauled with a rope launched from the deck of the "Esmeralda" to the freight carrier that brought him over. Soon afterwards the Executive Officer Arturo Prat, on sick leave, also arrived on board, after paying a very good amount of money to another freight carrier that at first had resisted in bringing him over. Very brave rowers had absolutely refused to carry the personnel on board, not even if very well paid, but they could not resist the requirements from Lynch and Prat, who finally worked their way to the ship. Prat was just another one among the others who put their lives at risk and were able to get to the corvette and later back to shore.

When the boat was close to the ship's side it ran the risk of capsizing. Prat dived into the water and reached the ship swimming. A rope was launched and then he was hauled to deck where he worked intensely tyind one end of the rope to his waist and the other one to the mast, so as to have enough freedom and at the same time feel secure. Lynch had followed the same procedure at the quarter deck

By night time, and after arduous and intense work, Lynch was finally able to strand the ship by the bow off the now railway station of El Barón. From there they managed to launch cables. Prat got rid of his rope and directed the fasting maneuver, in order to leave, as there was nothing else to be done but go ashore and wait until que storm withered. The Navy Officers and crew ashore were able to rescue the people, and finished doing so around three o'clock in the morning, thanks to the brilliant effort displayed on board by Lt. Commander Prat. The last one to leave the ship was the Commanding Officer Lynch. Ashore were the General Commander of the Navy (currently that would be the Commander in Chief of the Navy), Francisco Echaurren, and the untiring Chief of Staff Juan Williams, and many others.

Once the storm was over and everything was calm, thanks to the appropriate measures taken by Juan Williams and his collaborators, plus the assistance of the "Ancud" and the Ocean Tug "Adela", que "Esmeralda" was saved, lifted, and towed off the shore to the dock.

Many times did Prat replace Lynch as acting director of the Naval Academy, and his activities there were brilliant, for he was constantly concerned with his responsibilities, and always considering justice, straightforwardness, and impartiality in internal disciplinary issues. His notes addresssed to the Navy's General Headquarters were always judicious, as were his requirements for the Naval Academy, revealing his honesty, incorruptibility, which always bore an ever present touch of humanity.

Ultima Modificación: Lunes 30 de Abril de 2001