Article 11 of the LOSC provides a rule concerning harbour works:
For the purpose of delimiting the territorial sea, the outermost permanent harbour works which form an integral part of the harbour system are regarded as forming part of the coast. Off-shore installations and artificial islands shall not be considered as permanent harbour works.. the meaning and role of ports on the baseline situation on the law of the sea and LOSC, Article 11 of the LOSC, harbour system, law of the sea, ports, Sulina dyke
