The US Navy lost amphibious assault ship Bonhomme Richard to fire damage. (US Navy)

US Navy (USN) leaders are touting the investments being planned for the country's naval amphibious fleet and associated resources, even as government analysts are questioning the costs of some of these acquisitions and the navy is studying requirements and maintenance issues associated with amphibious forces.

Admiral Lisa Franchetti, the chief of naval operations (CNO), confirmed that the USN and the US Marine Corps (USMC) will review amphibious warship readiness and maintenance issues on 8 April during a discussion with reporters at the Navy League Sea-Air-Space 2024 global maritime exposition in National Harbor, Maryland.

The USMC could not fulfil US emergency-response force needs on two recent important occasions, Bryan Clark, senior fellow and director of the Center for Defense Concepts and Technology at Hudson Institute, told Janes on 31 March in an interview in advance of the symposium.

Marines had to forego disaster relief for Türkiye and the service could not provide similar amphibious operations for Noncombatant Evacuation Operations (NEO) for South Sudan, Clark noted.

With the loss of amphibious assault ship Bonhomme Richard

A full-scale model of Aselsan's first Deringöz AUV under development on display at UDT 2024. The company is set to start work on a smaller version this year. (Janes/Kate Tringham)

Aselsan has outlined plans to start expanding its family of Deringöz autonomous underwater vehicles (AUVs) this year as the first prototype under development progresses through its trials programme.

Speaking to Janes at the Undersea Defence Technology (UDT) 2024 conference and exhibition in London on 9 April, an Aselsan spokesperson told that the first prototype is making good progress following the successful completion of its first diving test in early March, and the company was optimistic that the system would complete development in the first or second quarter of 2025.

The AUV will conduct further navigation and guidance testing during April before progressing to trials in deeper water in May, the spokesperson said.

Meanwhile, the company is planning to start building a second, smaller version this year, which it aims to complete by 2026, according to the spokesperson. Aselsan is planning a family of three Deringöz AUVs in total, although no timeframe has yet been set for the development of the largest version.

A scale model of the active array for the miniature version of Düfas on display at UDT 2024. (Janes/Kate Tringham)

Turkish manufacturer Aselsan is progressing development of a miniature version of its Düfas low-frequency towed active sonar system for unmanned surface vessels (USVs), which it expects to complete this year.

Speaking to Janes at the Undersea Defence Technology (UDT) 2024 conference and exhibition in London on 10 April, an Aselsan spokesperson said the company has been working on the smaller version, dubbed Düfas-M, since 2022.

The company is now progressing through tests of the individual hardware components, which it expects to complete in the coming months. Sea trials of the complete system integrated onboard a Marlin USV will start in the second half of 2024, with a view to completing development by year-end, he said.

Developed under the leadership of Türkiye's Defence Industry Agency (SSB) to meet the requirements of the Turkish Navy, Düfas is designed for long-range anti-submarine warfare and surveillance.

Aselsan officially unveiled the full-scale version of Düfas for use on surface combatants in March 2024 following the successful completion of sea trials in late 2023.