Underwater RF communication suffers from unstable links and limited transmission range, which poses significant challenges for end-to-end data delivery in Delay Tolerant Networks (DTNs). To address this, we propose a redundant packet assignment method that estimates packet loss based on received signal strength(RSS) and dynamically adjusts the redundancy level using Reed–Solomon coding. Each node periodically transmits beacons, and RSS values are propagated through the network to estimate the minimum signal strength toward the destination. Based on this, the source node determines the number of redundant packets to attach. We implemented the method on Raspberry Pi devices and evaluated its effectiveness in a land-based experimental environment that assumes underwater conditions by inducing packet loss at defined RSS thresholds. The results show that the proposed method improves packet delivery ratios under varying link qualities and uses fewer packets than fixed-redundancy schemes when possible. These results suggest that RSS-based redundancy control can enhance the robustness and efficiency of DTN communication in underwater RF environments.