Subskimmer

The Subskimmer represents a unique convergence of maritime technologies, conceived to offer unparalleled operational flexibility. Originating from Submarine Products Ltd. in Hexham, England, during the late 1970s and first commercialized in 1983-84, its fundamental design principle is transformation. It functions as a conventional rigid inflatable boat (RIB) when on the surface, propelled by a gasoline outboard engine, enabling rapid transit.

However, its defining characteristic is its capacity for submersion. This transition is achieved through a sophisticated system that seals the combustion engine, deflates the buoyant inflatable tubes, and engages battery-electric thrusters. These thrusters, mounted on a rotatable cross-arm that also houses navigation systems, provide silent, low-signature propulsion underwater.

The heavy batteries are integrated into a keel tube for optimal stability, lowering the center of gravity. The central compartment serves a dual purpose, containing the inflation/deflation pump and miscellaneous equipment, underscoring the design's focus on efficiency and multi-functionality. The inclusion of a long snorkel for the outboard engine allows for submerged operation just below the surface, a critical feature for covert approaches.

The Subskimmer's journey through different manufacturers reflects its enduring appeal and evolving applications. Following its initial development and release by Submarine Products Ltd., the craft demonstrated impressive performance metrics: a surface range of 100 nautical miles at 20 knots, contrasted with an underwater range of 6 miles at 2 knots. This duality made it attractive for various roles.

A notable adaptation was the 'Seasearcher' variant, an orange-hulled version featuring high-intensity submersible spotlights, specifically designed for search and rescue operations, showcasing the platform's potential beyond purely military or clandestine uses. When Submarine Products Ltd. ceased operations, the manufacturing rights passed to Defence Boats Ltd. in Hexham by 1989. The design was further developed and produced in France by Serrico, under the designation 'Kraken 90,' by December 1992.

In 1993, KSA (Underwater) Ltd. acquired all intellectual property rights. The company later faced commercial challenges, leading to the acquisition of KSA (Underwater) Ltd., including the Subskimmer and Subtug product lines, by the Special Products division of Marine Specialised Technology Limited in 2009. This consolidation brought production to their Liverpool facility, integrating it with their existing surface craft manufacturing capabilities.

As of December 2014, production has been reported in Indonesia for its armed forces, indicating continued international relevance.

The Subskimmer's transformative capability is rooted in its ingenious engineering. The core mechanism involves the manipulation of buoyancy through its inflatable tubes. When inflated, these tubes provide the necessary displacement and stability for surface operation, accommodating the combustion engine.

For submersion, a controlled deflation process reduces the craft's volume and increases its density relative to the surrounding water. Simultaneously, the gasoline engine is rendered inoperable and watertight. Propulsion underwater is then exclusively handled by electric thrusters.

These thrusters are mounted on a versatile cross-arm that can rotate, allowing for precise directional control and maneuvering in three dimensions. This arm also serves as a platform for integrated navigation and sensor equipment, crucial for underwater operations. The strategic placement of heavy components, particularly the batteries within a reinforced keel tube, is vital for maintaining a low center of gravity.

This design choice enhances stability during submerged transit and reduces the likelihood of capsizing, especially in challenging underwater conditions. The snorkel system for the outboard engine is a testament to the design's focus on stealth, enabling the engine to operate while the craft remains partially submerged, minimizing its surface radar and visual signature.

The Subskimmer's strategic value lies in its inherent duality, offering a tactical advantage by bridging the gap between surface and subsurface operations. Its ability to rapidly transit over water and then transition to a stealthy underwater mode makes it suitable for a variety of specialized missions. For military applications, this could include covert insertion of personnel or equipment, reconnaissance, or mine countermeasures, where avoiding detection is paramount.

The speed advantage on the surface allows for rapid deployment over longer distances, while the silent underwater propulsion minimizes acoustic and visual signatures. The 'Seasearcher' variant exemplifies its utility in non-military contexts, demonstrating how the platform can be adapted for critical humanitarian or safety operations. The ability to cover significant distances on the surface and then conduct detailed, low-impact searches underwater provides a unique capability set.

This hybrid nature positions the Subskimmer as a niche but highly effective platform for scenarios demanding both speed and discretion, offering a distinct operational profile compared to traditional surface vessels or dedicated submarines.