Welcome to Gaia! ::

rofl

Beh. Mes gonna go look at some new purty sheeps.

Imperial Star Destroyer.
The Imperial 1 outguns the Keldabe signiffigantly and possesses a huge compliment of support vessesls within its hangar. Even factoring in the shield leeching ability of the Keldabe the Imperial Class would still be able to paralyze the mando ship with its compliment of 60 medium and 2 heavy Ion cannons.
In addition, the Naval abilities of the Mandalorians is not exactly something to write home about. The Imperial Starfleet cut its teeth fighting The Separatists, then their reminants, then rebellious systems before the organization of the Alliance. The crew of a Keldabe would be inferiorly trained compared to an Imperial Crew.

the tie is so un aero dymaic lol i like the x-wing the best and the republic gun ship

A Victory 1 would pose a sizeable threat to a Keldabe as well but not nearly as big a one as an ISD. A Victory 1's missile capabilities can make many ships take pause and a particularly tenacious crew can cripple bigger ships even as they're about to bite it. But a Victory 1's achilles heel is space combat, which is where the Keldabe can triumph over the smaller ship.
But one should also note that the Keldabe design is effectively on the black market for th highest bidder. Anyone who wants one and can afford one can buy the plans and construct them. This means that the quality of your average Keldabe is going to be inferior to that of any Imperial Produced ship.
Mon Cals are built by master shipwrights. SDs are made by KDY. Keldabes can be made by anyone with the sufficient funds and resources. This means that the people making them are not up to KDY or Dac quality. This inferior construction can kill an otherwise quality starship design.

Yeah. Basically they retconned it so that the first Star destroyers, while massive, became heavy frigates when the Imperiator rolled off the line and basically made every other Star Destroyer obsolete in comparison, much like what the HMS Dreadnaught did.
The Star Destroyer starship class was now set by the Imperator, now known as the Imperial, with the Venators and Victories relabled as Star Frigates. However, they are still called Star Destroyers by Imperial and Rebel alike, for the are big, powerful ships that have the dagger and tower look of its descendants. They were the first Star Destroyes and will continue to be called as such, but the technical Military specs label them as heavy frigates.

Acclamator-class... burn in hell.