A propagation-delay-aware MAC protocol, based on carrier sensing multiple access, is proposed. The design aims at maximizing the bandwidth utilization by keeping track of neighboring transmissions to avoid collisions, thus enabling interleaved packet transmission between different pairs of users. The performance is compared to several representative MAC protocols: the standard and slotted ALOHA, and three protocols designed specifically for the underwater acoustic environment, APCAP [1], DACAP [2] and T-Lohi [3]. Simulation results identify network settings (traffic load, node density, single/multi-hop topologies) in which each protocol offers the best performance.