*Review* **Review on Ship Manoeuvrability Criteria and Standards**

**Serge Sutulo \* and C. Guedes Soares**

Centre for Marine Technology and Ocean Engineering (CENTEC), Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisbon, Portugal<EMAIL_ADDRESS>**\*** Correspondence<EMAIL_ADDRESS>
**Abstract:** Possible reduction of the installed power on newly designed merchant ships triggered by requirements of the Energy Efficiency Design Indices (EEDI) raised concern in possible safety degradation and revived interest in manoeuvrability standards to make them capable to compensate for negative effects of underpowering. A substantial part of the present article presents a detailed analytical review of general principles laid in the foundation of consistent safety standards in the naval architecture and analysis of the existing IMO manoeuvrability criteria and standards. Possible ways of extension of the existing standards to embrace situations associated with adverse sea and wind conditions are discussed and modification of the present standards related to the directional stability is considered as one of the possible solutions. At the same time, it was found that introduction of additional standards for the ship controllability in wind is justified, and the second part of the contribution is dedicated to developing a theoretical basis useful for devising such standards. This includes obtaining a set of analytical solutions related to the steady motion in wind and analysis of wind-tunnel data which resulted in simple equations for conservative generalized envelopes for the aerodynamic forces which are especially convenient for standardizing purposes. Possible design decisions aimed at augmentation of the ship's capacity to resist adverse environmental factors are outlined.

**Keywords:** manoeuvrability standards; standardizing methodology; EEDI; influence of wind and sea waves; controllability in wind; ship aerodynamic characteristics


*4.3. Phylogenetic Clustering*

The Sunshine Cast heath data found phylogenetic clustering (a high NRI) on one of the nine regional ecosystems, in the dry, high, wind-buffeted, leached sand dunes, and along with a high NTI (clustered), which provides evidence for single clusters of taxa on the species pools, as opposed to several clusters evenly distributed around the tree [93]. This clustering, also found in global dune plant communities, leads to the conclusion that environmental filtering is at play [92]. This is supported by this regional ecosystem (RE 12.2.13) having a distinct community composition but overlapping in composition with a structurally taller system (RE 12.2.9), both growing in highly nutrient leached sands [94]. No other heath regional ecosystems were found to have a clustered NRI, but six had a clustered NTI, suggesting several clusters evenly distributed around the tree [93]. Phylogenetic clustering, due to the presence of closely related species, could indicate environmental filtering [23] and may be disadvantageous in terms of species competition. Yet, in long term heath studies in New South Wales, phylogenetic clustering became more pronounced over time since fire, in contrast to the expectation that increased competition would inhibit the coexistence of species with high niche overlap [95]. Furthermore, it is argued that closely related species may not necessarily compete more closely than distantly related ones, that filtering may not be the dominant mechanism, and that facultative interactions may play a part in this [14,96,97]. The co-occurrence of closely related species may be beneficial, for example, when facilitated by mutualistic exchange, such as through mycorrhizal symbiosis shared by co-occurring members of a clade, increasing the host's tolerance to environmental change [98]. Mycorrhizal strategies have been suggested as drivers of heath assemblages in Western Australia and Brazil, with well-known strategies used by the distinctive heath families Ericaceae, Orchidaceae, and Myrtaceae [99,100]. For the Sunshine Coast heaths, whose phylogeny is consistent with the general theory of sclerophyll and heath derivation, there are indicators that environmental filtering is a driver of their assembly but hints that facilitation and mutualism may be factors contributing to their community assembly and their general pattern of phylogenetic clustering.


**5.2 Blockchain**

Blockchain technology can improve the security and privacy of IoT-enabled energy management systems. Using a decentralized, tamper-proof ledger, blockchain can help prevent unauthorized access and data manipulation, ensuring the integrity and security of energy management systems [12]. Additionally, blockchain can facilitate secure, peer-to-peer energy transactions, enabling more efficient and flexible energy management solutions (**Figure 5**).

Blockchain technology addresses critical concerns related to data security, privacy, and transparency in IoT-enabled energy management. By creating an immutable and transparent record of energy transactions and data exchanges, blockchain ensures data integrity and prevents unauthorized tampering. Decentralized and peer-topeer energy trading becomes feasible, enabling direct transactions between energy producers and consumers. This disintermediation can lead to more efficient utilization of energy resources and greater flexibility in energy management. Blockchain's auditability also aids regulatory compliance, which is crucial in regulated energy markets. Energy certificates, carbon credits, and other compliance-related records can be securely stored and verified on the blockchain.