The lead vessel of Kelvin Class Light Cruiser design (USS Kelvin A) was the first vessel of her class to undergo a moderate refit using technology used in the Tikopai Class Heavy Cruiser, which includes an enhanced sensor package and blast doors on the torpedo shroud. The upgraded nacelle is unique to this refit.

My original Kelvin Class Light Cruiser can be found here: http://www.furaffinity.net/view/11540240/

And the Tikopai Class Heavy Cruiser by captshade can be found here: http://captshade.deviantart.com/art.....View-442631291