Tell me the lowest date commissioned for iron rmsrhone and gross tonnage less than 2,738
CREATE TABLE "list_of_rmsp_company_vessels" (
  "ship" text,
  "date_commissioned" real,
  "gross_tonnage" real,
  "propulsion" text,
  "material" text
);
SELECT MIN("date_commissioned") FROM "list_of_rmsp_company_vessels" WHERE "material"='iron' AND "ship"='rmsrhone' AND "gross_tonnage"<'2,738';