Assistance Towing Endorsement. This course is approved by the NMC for the Assistance Towing endorsement, and may be added to either an OUPV or Masters license. It is designed for boat captains who would like to tow a disabled vessel for a fee. Captains are required by the USCG to hold an Assistance Towing Endorsement on their Merchant Mariner Credential to be able to assist vessels that have run aground, are disabled, or have run out of fuel. Course is 4 hours in length and covers towing equipment and towing forces.