Let alone pl an south sea Fleet, they even can't be compared against other regional navies like RSN, RMN and other
The doctrine of the VPN , sister, is defensive in nature. They have the firepower to bleed any interloper fleet to their waters. The Vietnamese would not go beyond their supply lines due to the auxiliary limitations. Because of this aspect, they are a factor that concerns Chinese plans to expand into the western portion of the south sea fleet. In this case, i suppose it is best to support VPN growth to counter PLAN's growth and forays in this region of interest.