The Sina-7 appeared to be a 2,000-2,500 ton vessel armed with one 76mm gun, missiles, and a helicopter. Basically its an improvement over the earlier Jamaran class corvettes. Two of these have been put into service so far. Until the Sina-7 came along the Jamaran class was the largest locally built surface warship in Iran. One of the Jarmarans was assigned to the Caspian Sea, the other to the Indian Ocean. The Jarmarans were described as “destroyers” when first announced (as under construction) five years ago. In fact, it's a 1,400 ton corvette. The new ship has a crew of 140 and is equipped with anti-aircraft, (one 40mm and two 20mm cannon, four small missiles) anti-submarine (six torpedoes), and anti-ship (four C-802 missiles) weapons. At the moment, the Jarmaran seems to be filled mostly with hope and press releases. The navy made a point that the Sini-7s were better built than the Jarmarans.
The Iranian navy could certainly use some new warships. Currently, the only major surface warships it has are three elderly British built frigates (1,540 tons each) and two U.S. built corvettes (1,100 tons each). There are about fifty smaller patrol craft, ten of them armed with Chinese anti-ship missiles. There are another few dozen mine warfare, amphibious, and support ships. The three most powerful ships in the fleet are three Russian Kilo class subs. There are about fifty mini-subs, most of them built in Iran.
All that's been heard of from Iran's naval shipbuilding facility at the Bushehr shipyard are reports of labor problems. There have been strikes and lockouts as well as complaints of poor designs and sloppy management. Iran has, for the last two decades, announced many new, locally made, weapons that turned out to be more spin than substance.
Iran does have commercial shipbuilding firms that produce merchant ships that are larger than destroyers. Thus it was believed that Iran could build something that looks like a destroyer. The Jamaran class ships have Chinese C802 anti-ship missiles, but a lot of the other necessary military electronics are harder to get and install in a seagoing ship. Iran has coped by using commercial equipment. This does not make for a formidable warship but does enable high seas operations.
Iran is trying to expand its growing (slowly) naval power on all its coasts (Caspian Sea, Persian Gulf, and Indian Ocean). Thus, for the last four years, Iran has had one or more of its few surface warships working with the international anti-piracy patrol off Somalia. This was the first time since the 1970s that the Iranian Navy has conducted sustained operations outside its coastal waters. Despite their own Islamic radical government, the Iranian sailors have got along with the other members of the patrol, including the United States (which is officially the "Great Satan" back home). Encouraged by this, Iran announced that it would send more of its warships off to distant areas, mainly to show the world that Iran was a naval power capable of such reach.
Technically, the Iranians can pull this off but just barely. And this is mainly because, in the last decade, Iran has been building some larger warships. Not really large but big enough to take trips across the Indian Ocean. Two years ago, for example, the Iranian Navy sent its first domestically built destroyer, the Jamaran, to sea. In two years it hopes to do the same with the larger Sina-7s. But both these vessels are hastily built by yards with no experience in building surface warships. That means a lot of mistakes will be made. Moreover, the Iranians cannot get modern weapons and are equipping these ships with whatever they can scrounge up.