VESSEL REVIEW | Rio Iro & Rio Guadalmedina – Spain's Guardia Civil police adds interceptor pair to Strait of Gibraltar patrol fleet

Spain’s Guardia Civil national police force has taken delivery of two new fast patrol boats in a series built by local shipyard Aister.

Rio Iro and Rio Guadalmedina belong to a series of eight aluminium boats ordered by the Guardia Civil to replace the earlier FRP-hulled patrol vessels in its Maritime Service (SEMAR). The newer vessels will be operated by SEMAR primarily in the Strait of Gibraltar off the provinces of Cadiz and Huelva on Spain’s southern coast.

Although all eight boats in the series were built with similar configurations, a number of improvements have been implemented with each new boat over the delivery period, which commenced in 2023. Modifications cover the bow railings, the ventilation equipment, the mounting of the lifting eyes, making the radar arch removable, and repositioning of the outdoor emergency battery inside the wheelhouse to protect it from the elements.

“It is a genuine step-change in high-speed aluminium interceptors,” Javier Rasilla, Managing Director of Aister, told Baird Maritime. “They are purpose-designed, waterjet-propelled patrol boats that exceed 60 knots, combining exceptional acceleration with very agile high-speed handling.

High transit speeds coupled with extended operating endurance

“The hull and control systems let the craft stop in about two boat lengths and execute controlled turns of less than two lengths while preserving stability — performance attributes that set them apart in this class.”

Rasilla said that the operator required fast response interceptors optimised for maritime security duties — patrolling, border control, anti-drug operations, and surveillance —with emphasis on speed, robustness, crew protection, and low-maintenance operation. The boats also needed to be capable of operating for up to 12 hours on prolonged patrols and cover ranges in excess of 400 nautical miles.

“The brief called for an aluminium platform capable of sustained high-speed patrols, excellent seakeeping, and crew ergonomics for extended missions.”

Each boat has an LOA of 17.7 metres (58.1 feet), a beam of 4.5 metres (15 feet), a depth of 2.4 metres (7.9 feet), a displacement of 26 tons, and space for up to four crewmembers.

Navigation can be done through the main helm station or through the flybridge. The latter can be used during days of clear weather or for situations requiring unobstructed 360-degree visibility.

The boats fill the need for a fast-reaction, survivable interceptor that can pursue and intercept suspect craft at very high speeds while protecting crew and enabling sustained operations.

“It brings a combination of high top speed, rapid acceleration, manoeuvrability and operational endurance that many existing platforms do not provide in a single package,” said Rasilla.

The propulsion setup consists of two MAN D2862LE463 1,800hp (1,300kW) inboard diesel engines driving Hamilton HTX42 waterjets via ZF 3055 gearboxes. This arrangement necessitated forced ventilation in the engine compartment via two fans and a wet-type Halyard exhaust.

The Guardia Civil opted for vessels capable of speeds in excess of 60 knots as suitable interception platforms for dealing with the semi-rigid, outboard-powered “lanchas” that traffickers often use to attempt to smuggle drugs via the strait.

“The propulsion is managed by electronic controls with dual-redundancy architecture for reliability and precise handling,” Rasilla told Baird Maritime. “The waterjet arrangement and control integration deliver exceptional acceleration and tight low-radius manoeuvring. There is also a protective rear platform for the jets and jet-disengagement features for rescue operations.”

Robust construction and ease of servicing to ensure long operational life

The electronics suite includes a Furuno package consisting of a FAR-2228 radar, a TZTouch plotter, and a DGPS. The other electronics are a Simrad autopilot, a Saab AIS transponder, Inmarsat equipment, VHF transceivers, CCTV cameras, an EPIRB, and a SART. The selection of electronics emphasised resilience and operational simplicity, according to Rasilla.

“Secure-mode AIS, redundant radios, integrated NMEA-2000 networking and satellite backup allow continuous situational awareness at high speeds and in contested or degraded comms environments. The electronics fit is also configurable to mission needs.”

Other key features of each boat include Shockwave seats that are adjustable and can mitigate the effects of acceleration and high-speed turns on the crew and stern deflectors that improve trim and visibility from the wheelhouse when the vessel transitions from a standstill position to planing even within just five seconds.

Onboard facilities include a galley, a dinette, a toilet, and a two-person belowdeck cabin. The planning table can be converted into an additional berth. Firefighting and rescue systems are also available on board.

The boats also feature virtual anchor functionality, jet disengagement for recovery, and road transportability if required.

“Maintenance and operability were prioritised,” said Rasilla, “The design features a TBO of 5,000 hours with routine engine service every 500 hours, and engines can be removed through an access hatch in under four hours, enabling re-engining in a single day. These choices reduce lifecycle downtime and supportability costs.”

The hull alloy and build are sized for a service life exceeding 20 years, including structural robustness to withstand aggressive ramming attempts during interceptions.

“The main design challenge was in achieving extreme speed and acceleration without compromising stability, habitability or safety,” Rasilla told Baird Maritime. “That demanded detailed hydrodynamic optimisation of the hull, precise integration of high-power propulsion (i.e., engines and waterjets), and ensuring crew survivability at high impact loads – all while keeping weight and structural stresses within limits.

“Integrating active systems (e.g., interceptors for rapid transition to planing) to preserve visibility and control also required careful system-level design.”

Rasilla added that fabricating an 18-metre high-performance aluminium hull to tight tolerances also posed technical challenges.

“Weld quality, alignment and structural reinforcement are critical for both strength and weight control. Installing and commissioning the two inboard engines, the twin waterjets, and the associated gearboxes and forced-ventilation systems required close coordination with suppliers and rigorous factory testing to guarantee performance and maintainability.”

Development of additional military-optimised variant

Rasilla said that Aister used the SEMAR interceptor project as an opportunity to expand its knowledge on high-speed hull optimisation, systems integration, and ergonomic layout for crews. The project also reinforced the value of early supplier collaboration (for the engines, jets, control electronics) and modular design choices that simplify maintenance, lessons that the company has already begun applying on an upgraded variant.

“While the design has already proven itself as a high-performance interception platform, we are now unveiling a specialised variant. This model inherits the core strengths of the earlier interceptor – speed, agility, and durability – but is further optimised for military use.”

According to Rasilla, notable features of this variant will include troop transport capability, the ability to accommodate modular mission payloads, ballistic protection panels, and a remote controlled mount for automatic weapons, allowing operators to perform defence and interception missions with enhanced safety and precision.

“These enhancements make it ideal for defence and security agencies seeking a vessel capable of both high-speed interception and broader tactical operations,” he told Baird Maritime.