SPM result is good enough to be used for application purpose. You can insert your STPM result as well but Im not sure if it gives any advantage in application process. But once you are accepted into the DME programme, whatever you have studied before does not give any sort of fast track/carry over credit so everybody have to follow the programme regardless of previous learning background.

After entering ALAM, you will have the chance to get sponsors from shipping company such as AET and MISC.