A partnership that includes naval architecture firm Icarus Marine has introduced South Africa's first locally designed unmanned surface vehicle (USV).
The 9.5-metre (31-foot) Sea Serpent was developed through a collaboration between Noble Concentric Solutions (NCS), Legacy Marine, and Icarus Marine. It features IMO Level IV autonomous navigation, allowing it to interpret environments and avoid obstacles with minimal human intervention.
The USV can be used in both security and underwater survey applications. A sophisticated sensor suite and over-the-horizon communication links enable persistent surveillance.
“This project was a collaborative effort within South Africa’s maritime sector,” Eddie Noble, Managing Director at NCS, told Baird Maritime.
“Initiated by a systems‑level concept from NCS, the platform was developed by Icarus Marine with supplementary design input from Gloss Design, constructed by Legacy Marine, and delivered under integration oversight from NCS. The result is a genuinely multi‑stakeholder engineering programme and a national first in locally conceived, designed, and built autonomous-capable vessel development.”
Noble said the operational requirements were defined through the combined domain expertise of all participating entities, with each contributing insights from their respective involvement in maritime security, offshore oil and gas support, surveillance, patrol, and multi‑mission operational environments. This included detailed consideration of payload configurations, mission‑specific equipment suites, endurance expectations, and platform adaptability across diverse deployment scenarios.
“Given the objective of producing a vessel optimised for South African design, build, and operational conditions, significant effort was invested in systematically analysing mission needs, environmental constraints, and performance parameters.
"This rigorous requirements‑engineering process informed a hull and systems architecture capable of meeting the broad spectrum of identified use cases, and the resulting platform serves as a proof‑of‑concept vessel that validates the feasibility and performance of a locally engineered solution."
Developed as a proof-of-concept unmanned vessel for a client that wanted to evaluate the capabilities of autonomous vessels, Sea Serpent was designed to perform various kinds of operations with a broad selection of sensors, in effect making the USV a technology demonstrator.
“As such, the vessel design had to be capable of such broad functionality, whilst still having required speed, stability and stealth properties imbedded into the design,” said Noble. “Coupled with this was the full integration of all vessel systems and associated hardware control into the autonomous control system.”
“The design was developed from a clean sheet based on the requirements of the client,” added Gunther Migeotte, Executive Director at Icarus Marine. “Care was taken to come up with a modern yet functional design.”
The USV was developed to perform missions including anti‑piracy operations, harbour protection, mine countermeasures (MCM) support, intelligence, surveillance and reconnaissance (ISR), and electronic warfare. Noble said it delivers a powerful blend of autonomy, agility, and mission versatility.
“Its rugged design, high‑speed handling, and commercial off-the-shelf (COTS) based architecture make it a sustainable, future‑ready solution for modern maritime forces seeking to expand capability without expanding crew requirements,” Noble told Baird Maritime. “Far more than a proof‑of‑concept craft, it provides a fully functional testbed through which the armed forces can evaluate emerging technologies, refine operational concepts, and build the foundational knowledge required for integrating autonomous systems into their fleet.”
Noble explained that by operating an actual platform rather than relying solely on simulations or paper studies, the client can gain practical insight into autonomy behaviours, command‑and‑control workflows, and the logistical and maintenance demands of unmanned operations.
“This platform enables structured experimentation across navigation autonomy, sensor integration, remote command architectures, and multi‑mission payload deployment. Such hands‑on evaluation is essential for validating requirements, identifying capability gaps, and informing future procurement decisions. It also allows operators, engineers, and mission planners to develop the tactics, techniques, and procedures that will ultimately govern how USVs are deployed alongside manned assets in real‑world missions.”
Noble remarked that Sea Serpent supports the development of a coherent national USV doctrine by allowing the armed forces to explore roles such as persistent ISR, force protection, MCM support, and distributed maritime operations.
Through iterative testing and feedback, the client can assess how unmanned platforms enhance situational awareness, reduce risk to personnel, and expand operational reach in both littoral and offshore environments.
The USV’s propulsion system consists of a single Volvo Penta D4-600 inboard engine with stern drive, which Noble said was chosen for simplicity of installation and electronic control by the autonomous stack.
“Ideally, two engines will be installed for reliability and redundancy. However, this configuration [i.e., one engine] was chosen by the client as the vessel was to serve as a proof-of-concept craft to be used for further test and evaluation of core capabilities before the design is finalised for production.”
According to Noble, the Volvo Penta inboard is well‑suited to the USV because it combines high power density, fuel efficiency, and proven marine reliability in a compact package. The D4-600 delivers strong torque across the rev range, which is ideal for precise low‑speed manoeuvring as well as sustained transit speeds, both of which are critical for unmanned missions.
“Another important factor of the Volvo Penta stern drive is its small footprint,” added Migeotte. “The engine room could be kept small, allowing suitable space for a helm station. The helm station was not a ‘must have’ requirement from the client, but past experience designing USVs has shown that an onboard helm makes the operation considerably simpler when coming into port or during in-port operations.”
“The stern drive configuration adds further advantages to the USV by offering excellent manoeuvrability, trim control, and hydrodynamic efficiency,” said Noble. “Being able to trim the drive improves seakeeping, fuel economy, and speed across varying load and sea states, while steerable drive enables tight turning circles and precise track‑keeping, which are important for survey, patrol, or inspection missions.”
Noble explained that the propulsion configuration was deliberately selected for its mechanical simplicity and high reliability, ensuring seamless integration with the autonomous control system. The design prioritises straightforward, deterministic control behaviour over complex or maintenance‑intensive solutions, enabling robust autonomous operation with minimal intervention.
“Being of compact design as well as the high propulsion efficiency made the Volvo Penta duo-prop stern drive an excellent choice,” Migeotte told Baird Maritime. “It allowed the vessel to achieve the high speed and long endurance not easily achievable with other types of propulsion.”
The USV boasts a standard navigation suite consisting of a Furuno radar and navigation display, an AIS/GPS, weather stations, a compass, and an echosounder, which are all standard vessel equipment easily integrated via the N2K CAN bus to allow for easy integration into the autonomous control system. Situational awareness is enhanced by four fixed onboard IP cameras and further supported by a high-specification electro-optical/infrared camera system.
The autonomous control system from Robosys Automation provides full IMO Level IV autonomy. The vessel engine interfaces are also easily nitrated by means of Volvo Penta’s real-time monitoring system. Onboard systems monitoring and control (of the auxiliary systems, fire and bilge alarms, hatches, navigation lights, horn, mission bay, etc) are also performed by the Robosys control system, thus providing for full autonomous control of the vessel and its systems.
“Sea Serpent platform has been engineered around predominantly COTS electronic subsystems to maximise supportability, streamline logistics, and ensure long‑term spares availability,” said Noble. “Significant effort was invested in the overall system architecture to achieve high operational reliability despite the use of COTS components. This includes the integration of subsystem redundancy, fallback operational modes, and fail‑safe design principles throughout the vessel’s control and mission‑critical functions.”
Provisions for anti‑jamming and anti‑GPS‑spoofing capabilities have also been incorporated into the baseline architecture. These features are available as modular upgrade packages, enabling clients to select enhanced resilience measures according to mission requirements.
The deck equipment is intentionally minimised, limited primarily to essential fittings such as towing bollards, cleats, and associated hardware. Structural reinforcement provisions have been taken into account to support the optional installation of a small‑calibre, remote‑controlled weapon station, ensuring deck load compliance and stability margins under various mission configurations.
“The foredeck has been structurally engineered as a modular, multi‑mission zone,” added Noble. “This area can be configured as a mission bay capable of accommodating a range of payloads, including UAV support systems, over‑the‑side handling/winch equipment, or compact surface‑to‑surface missile modules.”
To enhance vessel handling across diverse sea states and mission profiles, the USV is equipped with a Humphree active stabilisation system, which delivers real‑time dynamic trim and roll compensation. This can significantly improve platform stability during high‑speed transits, rapid acceleration, and tight manoeuvring.
“By maintaining a more stable operating envelope, the system not only improves vessel responsiveness but also optimises the performance, accuracy, and operational efficiency of onboard sensors and effectors, particularly during precision navigation, ISR tasks, and weapons employment,” Noble remarked.
Development of Sea Serpent posed challenges, particularly in the integration of its many diverse features.
“It was challenging to arrange the spaces on board in a functional way so that there was a helm station, a payload bay, an electronics compartment, and an engine room in such a small boat,” Migeotte told Baird Maritime. “Coupled with this was ensuring the boat weight and centre of gravity remained within limits. Getting this right on a small craft is more difficult than on larger vessels.”
“The real complexity lay in integrating a constellation of onboard systems – i.e., navigation, autonomy, communications, power, auxiliary systems, etc – into a single, coherent platform capable of operating reliably in unforgiving marine environments,” Noble added. “The vessel’s success depended on our treating it not as a boat with electronics, but as a distributed system where every component influenced the behaviour of the whole.”
Noble said power management added another layer of complexity. The USV’s compact platform had to support high draw systems alongside sensitive navigation and autonomy electronics, and electrical noise, voltage fluctuations, and peak‑load events all posed risks. Delivering clean, stable power to critical systems demanded isolation strategies and redundancy planning.
“Sensor fusion was equally demanding,” said Noble. “The vessel relies on multiple sensors, which are integrated into a reliable navigation picture requiring robust filtering and failover logic. The autonomy stack can only perform as well as the data it received.”
Communications integration also presented challenges, as the USV needed to be able to maintain control and telemetry links across varying ranges and conditions, using RF and satellite pathways. Seamlessly switching between these links, managing bandwidth, and ensuring secure, low‑latency communication required a carefully layered architecture with robust fallback modes.
“Finally, all of this had to fit into a small, harsh, constantly moving platform,” Noble commented. “Safety and compliance added further constraints, from independent kill‑switch pathways to redundant control mechanisms.
“In the end, Sea Serpent’s greatest achievement was not any single subsystem, but the orchestration of all of them. Its development demonstrated that building an autonomous vessel is less about hardware and more about harmonising complex, interdependent systems into a resilient, intelligent whole.”
In Noble’s view, designing and building Sea Serpent led to a deep appreciation for the importance of starting every autonomous vessel project with a disciplined systems architecture.
“The experience showed that defining interfaces, data flows, timing requirements, and failure modes early prevents the occurrence of integration bottlenecks that emerge when hardware and software evolve independently,” he told Baird Maritime. “This architectural foundation will be a non‑negotiable element of all future builds, ensuring that each subsystem fits into a coherent, predictable whole.”
The team also learned that autonomy is fundamentally an integration challenge rather than a purely software challenge. The performance of the autonomy stack depended heavily on the consistency, timing, and validity of the data it received.
“The physical realities of the platform underscored the importance of early attention to equipment layout and installation, cable routing, and weight distribution,” said Noble. “These factors proved to be some of the most critical determinants of system reliability and maintainability. Incorporating them from the earliest design stages will reduce rework, streamline integration, and improve long‑term serviceability.”
| Sea Serpent | |
|---|---|
| SPECIFICATIONS | |
| Type of vessel: | USV – Naval and survey |
| Designer: | Icarus Marine, South Africa; Gloss Design, South Africa |
| Builder: | Legacy Marine, South Africa |
| Length overall: | 9.5 metres (31 feet) |
| Main engine: | Volvo Penta D4-600 inboard |
| Propulsion: | 2 x propellers |
| Electronics supplied by: | Noble Concentric Solutions |
| Display: | Furuno |
| Radar: | Furuno |
| Monitoring system: | Volvo Penta |
| Cameras: | 5 |
| Other electronics: | Robosys Automation control system |
| Other deck equipment: | Towing bollards |
| Other equipment installed: | Humphree stabilisers |