The Fraiser is the lead ship of the first commercial ship produced after the reveal of the Stargate programme to the world. The conception for this vessel was to be a ship capable of being configured quickly for many purposes, from a Hospital ship in this case, to anything from a pure freighter, a mining ship, a commercial passenger ship, or for military purposes as a large troop ship (which would be armed of course).
The configurations are made by virtue of swapping out containerised modules beamed on and off the ship to give the desired ship type required. The vessel is quite large, being almost 800m long.