 In 1844, he was granted permission to start a flour mill with a daily capacity of 75 "fanegas" on the Guadalupe River in San Jose.In 1845, Sainsevain married Paula Suñol (1827–1883), whose father Antonio Maria Suñol owned Rancho Los Coches.In 1846, Sainsevain and Charles Roussillon built a schooner (the "Antonita") on the beach at Santa Cruz.