This stamp issued by Chile in 1986 for the 540 anniversary of the founding of the town Valparaiso shows us the Spanish ship SANTIAGUILLO, also given as SANTIGUILLO.
Noting found on this ship when and where built, she was used by the Spanish conquistador Juan de Saavedra (?-1554) in the first expedition to Chile. (Most probably built in Peru and a small coastal vessel.)
He got orders from Diego de Almagro ( at that time in Chile) to reconnoitre the coast of Chile, in the SANTIGUILLO that had brought reinforcement from Peru.
When he arrived in September 1536 at Alimapu the farthest south he got, he rename Alimapu in VALPARAISO, named after his birthplace Valparaiso de Arriba in Spain.
I found the name SANTIAGUILLO back in 1544 when she was used by a naval expedition together with the SAN PEDRO. The expedition was under command of Juan Bautista Pastene to reconnoitre the south-western coast of South America.
The expedition left Valparaiso heading south, although Pastene did not reach Strait Magellan, but most of the Chilean coast was explored to the Bay of San Pedro, and he made landings at what now is named Concepcion and Valdivia which was later named in honor of the commander.
When he encountered severe storms further south he returned to Valparaiso.
Chile 1986 40p sg1053, scott?
Sources: Various web-sites and Wikipedia.