Tangier is a major city on the northern tip of Morocco directly at the Strait of Gibraltar. This makes the city a major shipping port.
Two H.A.R.M. employees working at Facility 4524 noticed a ship just off the coast at their location. Not knowing if the ship was there to pick up Cate Archer or just heading to Tangier, the two thugs decided to keep an eye on it before reporting it to their boss Dmitrij Volkov.
Tangier on Wikipedia