Excalibur-class isn't actually one of Pat's - it's an old SFM mesh, though I can't remember the exact credits. The Hyperion-class was originally for the Arizona-A; The Pathfinder-class Miranda was of course the title ship of the sim, but so was the Jupiter-class - that class was originally created for the Miranda-A. Incidentally, the Miranda originally was a Kelvin-class ship - think a Soyuz-esque Sovereign. Pat had a habit of blowing ships up when he got bored with them. Even the Miranda-B got pretty badly beaten down once so that he could redesign her.
I thought back then it can but all ship designs after the Refit cant cus they used Warp power for phaser power instead of the Phasers having there own power source
If you're referring to why the refit 1701 couldn't fire phasers during the "wormhole" sequence in TMP, it was because the phasers used warp power AND the warp engines were in "antimatter imbalance." It is my impression that under normal circumstances they could be fired at warp speed.
Credit: W.I.P. Master Situation Display of the U.S.S. Phobos by Bmused of SciFi-Meshes.Com Warning: Large Image. http://img222.imageshack.us/img222/1664/loknarmaster2h.png
According to both Mr. Scott's Guide to the Enterprise and the TNG Technical Manual (not to mention the laws of physics), phasers can't be fired at warp for a simple reason: a phaser beam travels at the speed-of-light. Thus there is no way for any ship travelling at Warp One or above to fire a weapon that is going the same speed or slower than it. Torpedoes, on the other hand, are totally acceptable.
According to video footage in TOS, the speed of a phaser beam varies between that of a thrown baseball and faster than most starships at warp, depending on the needs of the script writer...
The same type of rule regularly applied to the speed of the turbolifts and how long it took them to shuttle our heroes from point A to point B. The most egregious example of this was the full minute of screen time it took Spock and the Romulan commander to travel from the bridge to deck 2 at the end of "The Enterprise Incident". Even twentieth century hydraulic elevators don't move that slowly.
I'm just going by what is seen on screen. Kirk orders phasers fired at warp speed in TMP. The only reason given for his order being countermanded is that the phasers were off-line due to engine imbalance. If it were impossible to fire phasers at warp at all then Kirk likely never would have given the order. And if we go by the actual laws of physics then we have to throw out most of what we see on Trek..