This paper proposes a new heterogeneous network topology and a routing algorithm for a marine communication system involving ships and other marine vessels from a terrestrial point on the shore. Topology involves the use of a collection of Long-Term Evolution (LTE) systems and Wi-Fi mesh networks. There are multiple clusters/ships in the network, with an LTE system centered around each cluster. Communication between the clusters happens through LTE, and within the cluster mesh, networking is employed. Every end user in the ship has access to the server application by means of mesh networking from the respective access point in the cluster/ship. The routing algorithm is designed based on the best signal-to-interference-plus-noise-ratio path and minimum delay combination, which selects the best modulation scheme and hence the best data rate. The algorithm employs a new parameter that is derived from signal-to-interference-plus-noise ratio. The topology along with the algorithm provides a connection with a maximum coverage distance of 180 km and minimum data rate around 0.6 Mbps with 2 interconnection clusters. The presence of more interconnection clusters makes the coverage distance, data rate, and reliability greatly improved. Open source network tool Network Simulator 3 is used for the topology design, algorithm implementation, and simulations. The proposed topology and algorithm when implemented can be used to provide long-distance sea communication with improved reliability and higher data rate.