After conducting research, I could not find any information about a boat ramp named Port Promontory Drive in Comanche County, Texas. It is possible that the ramp has not been documented or that it may be located in a different county. Therefore, I cannot provide information about the type of boat ramp, the width, the body of water, or the permitted craft.

It is important to note that boat ramps in Texas are typically managed by local entities such as cities, counties, or park districts. These entities may have different rules and regulations regarding boat usage and access. Therefore, it is recommended to contact the relevant entity or check their website for information about a specific boat ramp.