The Tamarian deep space cruiser was an advanced starship-cruiser design utilized by the Tamarians in the 24th century. Information on this class was sparse. Tamarian deep space cruisers were armed with phasers and were comparable in size, but superior in power, to that of a Federation Galaxy-class starship.
Tamarian technology allowed Tamarian starships to create a particle scattering field in the ionosphere of a planet. By projecting a particle sustaining beam into the upper atmosphere of said planet, they could effectively inhibit transporter and communication technology to or from the planet's surface. The field was created with a polarity coil generator, which was located on Tamarian starships in a heavily shielded section, aft of the warp drive.
Between 2268 and 2368, Tamarian starships had encountered Federation vessels seven times. Each meeting was without incident, but formal relations were never established because communication was not possible. The last encounter occurred on stardate 25058.4 with the SS Shiku Maru.
In late 2367, a Tamarian deep space cruiser arrived at El-Adrel IV where they began transmitting a subspace signal toward Federation space. Three weeks later they were approached by the Federation starship USS Enterprise-D. After a failed attempt at communication, the captains of both starships were beamed to the surface of El-Adrel IV, whereafter, the Tamarians projected their particle scattering field around the planet. The Enterprise-D was finally able to disable the polarity coil generator of the Tamarian starship before the two ships exchanged phaser fire.
In the brief exchange between the two vessels, the Tamarian ship inflicted damage that resulted in the loss of forty-eight percent of the Enterprise-D's starboard shields and a complete loss of its forward shields. In the Enterprise-D's retaliatory attack, it caused no damage to the Tamarian vessel. A second volley from the Tamarians completely disabled the shields of the Enterprise-D. (TNG: "Darmok")
Background information Edit
The name "Tamarian deep space cruiser" appeared on an okudagram appearing at the beginning of the episode. According to the script, the Tamarian starship, was described as "formidable looking," a "mysterious, powerful-looking vessel," and "slightly more robust" than the Enterprise-D.
For information about the history and design of this model, please see: Studio models. The Star Trek Customizable Card Game gives its name as Tama and calls it a Darmok class ship. A visual effects model of this ship was auctioned off on the 40 Years of Star Trek: The Collection at Christie's. 
The images shown here are from the original unremastered version of the episode.