In most existing handshake-based collision avoidance protocols, nodes in the proximity of the transmitter or receiver are kept silent during an ongoing communication session. In this paper, we utilize the long propagation delay in the underwater acoustic channel and the (possible) sparsity of the network topology to increase network throughput. We formalize conditions for which a node can transmit even when it is located one-hop away from a node participating in another communication session. We consider these conditions as problem constraints and form a distributed collision-avoidance handshake-based protocol, which jointly applies spatial and time reuse techniques. Our simulation results show that at a price of complexity, our protocol outperforms a recently proposed handshake protocol in terms of throughput and transmission delay.