"Cardinal" fast frigate intelligence report.
Star Fleet Intelligence (SFI) has given this report a 65% reliability rating.

General Specifications:

Length: 58m (Confirmed)
Width: 51.25m (Confirmed)
Height: 17.25m (Confirmed)
Max Warp: 8.1 (Confirmed)
Cruise: 6.2 (Estimated)
Max. Impulse: 0.85 lightspeed (Estimated)
Crew: 6-15 (Estimated)

Armaments: Two disruptors (fwd); one torpedo launcher (fwd).

Type: Fast Frigate

About Ship: In 2266, the Romulan Star Empire (RSE) sent a lone ship through the Neutral Zone into Federation space, to test the Federation's defenses. Although the cloaked vessel was easily able to destroy two starbases before discovery, it was located, tracked, and ultimately destroyed by a single Federation starship. The RSE realized that in the hundred years since their last conflict with the Federation, all their efforts to modernize their fleet had simply not resulted in any significant advantage over their Federation adversaries. RSE diplomats began making overtures to the Klingon Empire, seeking to trade key technologies that would enable them to deal with the Federation from a position of power.

In 2268, the Romulans struck a deal with the Klingons. They not only exchanged technology, but arranged to produce certain ships designed by the Klingons which would fill percieved gaps in the Romulan's capability. The Cardinal is one of those ships.

The Cardinal (Romulan designation unknown) is derived from the Klingon D6 fast frigate. It was intended to serve as a merchant escort and as a fast raider. An initial batch of six ships were purchased from the Klingons in 2268, along with several D-8 battlecruisers. While the battlecruisers were more than satisfactory, the D-6 was much slower at sublight and required some modification before it was deemed suitable for front-line deployment. The RSE obtained license to build their own version of the D-6, modified accordingly.

The Cardinal (also known as "D-6R") is essentially a Klingon D-6 fast frigate with nacelles of Romulan design. The intercoolers for the Engineering section were relocated to short pylons atop the engineering section and additional shielding was added throughout the vessel. The entire engineering section was reworked to include a warp core of Romulan design, and a cloaking device was added. Original plans to add a plasma weapon in an underbelly pod were scrapped as too difficult to implement without a complete redesign.

The Cardinal is still in service, but is used mainly for patrol and rescue. It's role as a fast raider has been usurped by more modern designs.

Starfleet gratefully acknowledges the cooperation and assistance of its counterparts in the Klingon Imperial Defense forces for providing much of the historical data regarding this vessel.