Documented here:
https://winscp.net/eng/docs/scriptcommand_open
https://winscp.net/eng/docs/session_url

Though way easier is to have WinSCP GUI generate a script template for you:
https://winscp.net/eng/docs/ui_generateurl#script

finally found it but not exactly easy to find ..
open sftp://username:password@sftp.example.com/

Replace the sftp:// with the ftp://, if you keep using the FTP protocol.
I had been trying to force FTP using open username:passwd@ftp://site.com:21 but all i had to do was change the open statement to
open FTP://username:passwd@site.com job done :)

Hi all,
i have been thru the automation stuff but failing to find something very simple, winscp tries to keep using SFTP which is not supported by the ftp server at the far end. How do i tell winscp to only try to use FTP protocol ?
I thought i had found something using the rawconfig but it still goes off and uses SFTP .. head butt the wall time...