Mo. Rev. Stat. § 306.455

When the director of revenue issues a certificate of title for an outboard motor or vessel in the names of two or more persons, it shall be presumed that ownership of the outboard motor or vessel is held by the persons shown on the title as joint tenants with right of survivorship or as tenants by the entirety if the owners are husband and wife, unless at the time the application for a certificate of title is filed with the director of revenue, the application states that ownership of the outboard motor or vessel is held as tenants in common.