The IRIS Alborz, pride of the Iranian navy, isn’t much of a warship. Commissioned in 1971, the frigate is both long in tooth and lacking in teeth: Decades of sanctions have obliged Iran to jerry-rig it with homemade combat systems, well short of the firepower of equivalent vessels in the world’s major naval fleets.

The ship serves important symbolic purposes, though. It is a reminder that the Islamic Republic is a maritime state, if not quite a power. Its armaments, limited as they are, also advertise Iran’s indigenous weapons-making capabilities. When it sails out of its home port of Bandar Abbas on the Persian Gulf, the Alborz projects not power so much as defiance.

Right now, the vessel is serving symbolic functions on the far side of the Arabian Peninsula, as reassurance and recognition for a key ally: the Houthi rebels of Yemen, who have been attacking international shipping on one of the world’s most important sea routes. They have also fired missiles in the direction of Israel, in support of another Iranian ally, Hamas, and have also been on the receiving end of U.S. and U.K. military strikes.