Flender NAVILUS Multiple-Input Single-Output Marine Gearbox

Overview

The Flender NAVILUS Multiple-Input Single-Output Marine Gearbox represents the apex of modern maritime power transmission technology. In the demanding offshore and maritime logistics sectors, modern vessels frequently require massive propulsion power coupled with exceptional operational flexibility. This highly specialized gear unit architecture allows two or more prime movers—such as marine diesel engines or high-capacity electric motors—to drive a single output propeller shaft simultaneously. This design provides marine engineers with a highly scalable propulsion platform, ensuring vessels can maintain optimal fuel efficiency at cruising speeds while retaining the capability to deploy maximum torque when required for heavy towing or high-speed transit.

Seven Star LLC operates as a specialized technical supplier, commercial vendor, and professional B2B procurement consultant, distributing these advanced maritime gear units to offshore fleets, shipbuilding contractors, and port authorities across the Sultanate of Oman, Muscat, and the wider GCC region. By offering the highly resilient Flender NAVILUS multi-engine platform, we enable our maritime clients to modernize their fleet propulsion systems. This ensures maximum vessel uptime, superior shock load resistance, and strict compliance with global maritime efficiency standards, safeguarding critical marine logistics operations from the deep-water Port of Sohar to the Port of Salalah.

Operational Principle

The core power transmission and operational principle of the Flender NAVILUS Multiple-Input Single-Output Marine Gearbox revolves around synchronized multi-pinion engagement and dynamic clutch control. In a standard twin-engine configuration, the kinetic energy from two independent prime movers enters the gearbox via separate input shafts. Each input shaft drives a precision-machined pinion gear, and both pinions simultaneously mesh with a single, massive central bull gear connected directly to the output propeller shaft.

To provide absolute operational flexibility, this gear unit integrates advanced, hydraulically actuated multi-disc clutches or pneumatic torsional couplings (such as the PNEUMAFLEX series) on the input shafts. This allows the vessel’s automated propulsion control system to dynamically engage or disengage individual engines while the propeller remains in motion. During partial load operations, such as low-speed patrolling or dynamic positioning, one engine can be completely decoupled and shut down, pushing the remaining active engine into its most fuel-efficient load range. When maximum propulsion thrust is demanded, the second engine is seamlessly synchronized and engaged, doubling the output torque delivered to the propeller without interrupting the vessel’s momentum.

Engineering Design of the Flender NAVILUS

The structural and metallurgical engineering design of this marine gear unit is purpose-built to withstand the severe multi-axis forces generated by offshore maritime environments. The gearbox housing is fabricated from highly rigid marine-grade nodular cast iron or heavy-duty welded steel. Utilizing advanced Finite Element Analysis (FEA), the casing is optimized to resist the massive structural deflections and torsional twisting that occur in a vessel’s hull during heavy seas, ensuring the internal gear alignment remains absolutely precise under all operational conditions.

Internally, the gearing is forged from premium carburized alloy steel, subjected to advanced case-hardening and high-precision CNC profile grinding. This ultra-smooth surface finish minimizes sliding friction, drastically reduces structure-borne acoustic emissions, and prevents micro-pitting over continuous duty cycles. Furthermore, the gearbox features a heavy-duty, integrated marine thrust bearing. This specialized bearing is engineered to absorb the immense, multi-directional axial thrust generated by the vessel’s propeller, safely transferring these destructive forces directly into the hull structure and completely isolating the engine crankshafts from axial loads. The modular design also supports Power Take-Off (PTO) and Power Take-In (PTI) shafts, enabling the integration of shaft alternators or hybrid electric drives directly into the gear unit.

Key Features

• Multi-engine synchronization allowing multiple prime movers to drive a single output shaft for scalable propulsion.
• Dynamic clutch integration (hydraulic or pneumatic) enabling independent engine engagement and disengagement during operation.
• Extreme fuel optimization capabilities by allowing prime movers to operate in their most efficient load ranges during partial loads.
• Marine-grade, FEA-optimized housing designed to withstand severe hull deflections and extreme ambient offshore conditions.
• Precision-ground, carburized helical gearing delivering an exceptionally low acoustic signature and minimal vibration.
• Heavy-duty integrated thrust bearing engineered to safely absorb and transfer massive axial propeller forces into the ship’s hull.
• PTO (Power Take-Off) and PTI (Power Take-In) readiness for driving auxiliary shipboard alternators or supporting hybrid-electric propulsion.
• Full compliance and certification capabilities with all major maritime classification societies (ABS, DNV, LR, BV, RINA).

Industrial Applications

The extreme operational flexibility and torque density of the Flender NAVILUS Multiple-Input Single-Output Marine Gearbox make it an indispensable asset for a wide range of specialized maritime vessels. In Oman’s rapidly expanding offshore energy sector, these gearboxes are heavily deployed in Offshore Support Vessels (OSVs), Anchor Handling Tug Supply (AHTS) vessels, and heavy-duty ocean-going tugs operating out of the ports of Muscat and Sohar. These vessels require immense bollard pull for towing oil rigs, but also need fuel-efficient cruising capabilities when transiting between the shore and offshore oil fields.

Additionally, this multi-engine gearbox architecture is widely utilized across the GCC in RoRo (Roll-on/Roll-off) passenger ferries, luxury cruise ships, and naval patrol vessels where high redundancy and low acoustic emissions are mandatory. Sourced safely and efficiently through the specialized marine procurement network of Seven Star LLC, these gear units ensure that commercial fleets maintain maximum operational readiness. By providing unmatched propulsion redundancy, the risk of a vessel being stranded at sea due to a single-engine failure is eliminated, safeguarding both crew safety and critical maritime logistics schedules.

Technical Specifications

Call to Action

To submit a formal Request for Quote (RFQ), verify regional marine stock availability, or download complete mechanical CAD drawings and maritime classification datasheets for the Flender NAVILUS Multiple-Input Single-Output Marine Gearbox, please contact the industrial and marine power transmission division at Seven Star LLC today. Our technical application engineers in Oman are ready to assist with propulsion sizing, torque matching, and rapid commercial sourcing for your offshore fleet across the GCC.