NRP Almirante Gago Coutinho (A523) is a ship of the Portuguese Navy' Dom Carlos I-class survey vessels (ex-US Stalwart-class ocean surveillance ship adapted in Portugal for the execution of hydrography and oceanography surveys). Before transfer to the Portuguese Navy, Almirante Gago Coutinho was formerly USNS Assurance (T-AGOS-5) of the United States Navy.