## 1 Introduction  
Maintaining the energy efficiency with the reliability of the network in UWSNs is challenging. The nodes in UWSNs consume energy to communicate with one another. The limited energy is supplied to each node in UWSNs. The cost of the network increases by deploying the entire network again when the energy of the nodes is consumed [1]. By increasing the lifetime of the networks, more information forwarding can be achieved. Many protocols in the literature minimize the consumption of energy in UWSNs [2; 3]. The reliability of the UWSNs decreases when the packet delivery ratio (PDR) spoils and this happens due to channel properties [4; 5]. The maximum reliability of the networks can be achieved by designing protocols that address the unwanted channel parameters. By following this, maximum information reaches the desired target. The practical accomplishment of the energy efficient and reliable protocols is needed in situations such as underwater forecasting, pathfinding for underwater vehicles, oil leakage and spying [6]. UWSNs are well known to assemble the messages from the nodes and forward them in the direction of the final destination node (DNN). However, in sending information packets from underneath to top of the water surface, many challenges are faced such as multi-path fading, propagation delay and high bit error rate, among many others [7]. By facing these challenges, reliability and energy of the networks are affected. Thus, for the sake of improving networks reliability, many cooperative routing protocols have been designed [8; 9]. However, these protocols have not been energy efficient and thus have high energy consumption of the networks. The limited power is supplied to underwater networks and it requires much effort to change or recharge the battery [10]. Therefore, plenty of energy efficient protocols without cooperation are proposed to minimize the energy usage, but the PDR is reduced [11]. The destination (DSN) and relay nodes (RLNs) work together to transmit the information bags to the sink nodes in cooperative routing. Cooperative communication has two schemes: the first one is the fixed relaying scheme and the second is the adaptive relaying scheme [12]. Fixed relaying scheme has further two sub-schemes, i.e., fixed amplify-and-forward (AF) relaying and fixed decode-and-forward (DF) relaying. In AF relaying, the forwarder node receives the information packet and amplifies it and then transmits to the DSN. In DF, the forwarder node decodes the information, re-encodes it and transmits in the direction of the DSN [13]. Many cooperative and localization based protocols are designed for UWSNs [14; 15; 16]. These protocols need full localization information of each node. To get the localization information of each node, GPS or some measure of the received signal power is required, and, as a result, the cost of the networks increases [17]. In this paper, two routing protocols for UWSNs are proposed. The first proposed protocol is called localization free energy efficient routing (LFEER). The proposed protocol has an energy efficient mechanism which consumes minimum energy in data bags forwarding. The LFEER protocol defines the DSN selection criteria. The selection criteria for the DSN are set through a function. The function has three parameters. These parameters are: residual energy, number of hops and bit error rate (BER). The source nodes broadcast the information bags. The node which has the highest residual energy, the fewest hops and the lowest BER over the transmitting link is chosen as the DSN. If a mechanism for the selection of DSN is not considered, then all nodes which are in source nodes transmission range forward the information packets towards the final DNN. Hence the tremendous energy is consumed by all nodes, as a result the network is probable to die quickly. The second proposed protocol is called localization free energy efficient cooperative routing (Co-LFEER). It is the improved version of the LFEER protocol.