Signals Intelligence

Some navies have them and some do not. Signals intelligence (SIGINT) collection ships may seem like a niche capability, according to Dr. Thomas Withington, who specialises in radar, communications systems, electronic warfare (EW) and all things of C4I. “SIGINT ships operate beneath a thick cloak of secrecy, yet visually they may be among a navy’s most distinct vessels”, he suggested.

Only a few navies operate SIGINT ships, or plan to do it. Among them Poland which is in the process of acquiring two specialised vessels. On 14 January 2026, the launch of the nation’s second SIGINT ship, ORP Henryk Zygalski, took place in Gdańsk. ORP Henryk Zygalski is the final SIGINT ship built for the Polish Navy (Marynarka Wojenna) under the auspices of Project 107 Delfin. The first unit – named ORP Jerzy Różycki – was launched on 1 July 2025.

SIGINT is a highly complex mission. Dr. Withington noted in Naval Forces I/2025: “The secrecy of the mission is because SIGINT ships essentially have a single role; they listen. Typically, a SIGINT collection ship may patrol in international waters, but close to a nation, or area of interest. The task of the ship, and its crew, is to gather SIGINT from a country or region of interest. SIGINT concerns itself with collecting intelligence on happenings in the electromagnetic spectrum.”

According to Dr. Withington, SIGINT ships have a similar mission to the SIGINT-gathering aircraft (as shown in the German Persistent German Airborne Surveillance System; PEGASUS) but perform their tasks at sea. Like the aircraft, they can accommodate analysis who interpret the incoming COMINT (communications intelligence) and ELINT (electronic intelligence). Just as importantly, their interior space can house powerful computers to help crack encryption and to find the signals of interest (SOIs). Dr. Withington further explained: “These SOIs are often protected by low probability of deception/interception characteristics, precisely to mask them from detection. Topside, the ships can house large antenna arrays which collect these signals of interest. Like the SIGINT aircraft, comprehensive conventional radio communication and SATCOM allow the resulting intelligence ‘product’ to be shared.”

To return to Poland’s two new SIGINT ships, both units will be equipped with the mission-critical reconnaissance systems and will undergo sea trials. Ship-based ELINT systems will enable the acquisition of intelligence data across the entire spectrum of maritime ELINT as part of its SIGINT role.

The vessels constructed under the auspices of the Delfin programme are built by Saab as the prime contractor. Remontowa Shipbuilding S.A. in Gdańsk is subcontracted to construct the ships, with Polish company MMC supporting Saab with design work. Saab is fully responsible for supplying and integrating the advanced mission systems. Other entities within the Polish defence industry are also involved in the implementation of the project. Deliveries of the ships, once the next phase of onboard installation work and sea trials are completed, are scheduled in 2027 and 2028. Whether nations have dedicated SIGINT ships or not, the need to collect both COMINT and ELINT on the high seas is unlikely to diminish, Dr. Withington concluded. As the procurements in the Scandinavian and Baltic regions illustrate, keeping tabs on Russian naval and military activity drives the procurement of new vessels. A niche capability they may be, but SIGINT ships are a capability some navies cannot do without.