Submarine
Propulsion
Systems

Get In Touch

Silvercrest Submarines together with our Australian partner company SME (Submersible Motor Engineering) designs and manufactures bespoke submarine propulsion systems for manned submarines worldwide. Our Australian manufactured motors range from 3.7kW to 1,500kW configurations in 2-pole, 4-pole, 6-pole and 8-pole specifications, purpose-built for tourist submarines, luxury vessels, research platforms, and commercial underwater operations.

Unlike off-the-shelf motor suppliers, Silvercrest manufactures proprietary submarine propulsion systems with complete in-house lamination design and production. This vertical integration enables custom engineering solutions tailored to each submarine's operational requirements - from compact luxury submarines requiring lightweight 5-15kW thrusters through to high-capacity tourist vessels demanding 200-400kW propulsion systems for passenger operations.

Our submarine motors are designed specifically for horizontal-axis operation with robust thrust bearing assemblies to manage propulsion loads, distinguishing them from traditional vertical down-hole pump motors. Available in 316 stainless steel, Super Duplex, or hard-anodised marine-grade aluminium (6061 T6) construction, our motors are oil-filled and externally compensated for operational depths to 4,000 metres, with specialist units certified for 6,000-10,000 metre operations.

Silvercrest Submarines' manufacturing facilities in the United Kingdom, Australia, and USA provide global service coverage, whilst our ISO 9001:2000 certification ensures rigorous quality standards for design, development, manufacture, and testing of submersible electric motors. We also provide comprehensive repair, rewind, and refurbishment services for all submarine motor manufacturers, including Alstra, Aturia, Grundfos, Hayward Tyler, Hitachi, Mercury, Pleuger, Byron Jackson and Franklin.

Submarine operators seeking proven, British-engineered propulsion systems are invited to discuss their specific operational requirements with our technical team.

Get In Touch

Submarine Motor Range & Specifications

Silvercrest Submarines/SME manufactures submarine propulsion motors from 3.7kW through to 1,500kW in configurations from 24 Volts to 6,600 Volts at 50Hz or 60Hz frequencies. Our flexible design capabilities accommodate custom external dimensions, drop-in replacements for existing installations, and bespoke motor designs for unique platform requirements.

Power Range & Typical Applications

1kW - 50kW Motors: Ideal for luxury submarines, auxiliary thrusters, steering systems, and compact research platforms. Typical configurations include 5.5kW, 11kW, 15kW, 20kW, 30kW, and 40kW units in both aluminium and SS316 construction.

50kW - 150kW Motors: Standard propulsion for medium tourist submarines (16-28 passengers), research vessels, and commercial diving platforms. Common configurations at 75kW, 100kW, and 150kW provide reliable main propulsion for operational vessels.

150kW - 400kW Motors: High-capacity tourist submarine propulsion (36-48 passengers) and large research platforms. Typical installations include 200kW, 260kW, 300kW, and 400kW configurations for vessels requiring substantial continuous power output.

400kW - 1500kW Motors: Specialist high-power applications including large tourist submarines, underwater excavation systems, and heavy-duty marine engineering operations requiring exceptional propulsion capability.

Voltage Configurations: Silvercrest motors are available from 240VAC through to 6,600VAC, with specialist units manufactured at 10,000VAC for specific applications. Our proprietary insulation system enables motors up to 4,160V to utilise random winding construction, reducing size and weight whilst maintaining reliability for operation in hydraulic oil or bio-degradable compensation oils.

Construction Materials

316 Stainless Steel: Standard marine-grade corrosion-resistant construction suitable for saltwater and freshwater operations
Super Duplex: Enhanced corrosion resistance for demanding chemical environments and extreme operational conditions
Hard-Anodised Aluminium (6061 T6): Lightweight construction meeting military specifications whilst maintaining structural integrity

All motors feature external compensation for depth operations to 4,000 metres as standard, with specialist configurations rated to 6,000 metres and beyond.

Enquire About Our Submarine Motor Range

Engineering & Manufacturing Capabilities

Silvercrest Submarines/SME operates as a fully integrated manufacturing facility, producing our own laminations designed specifically to meet individual customer requirements rather than purchasing off-the-shelf rotor sets. This approach enables bespoke motor designs that are more efficient and generally smaller in both diameter and length than comparable products for any given power rating.

In-House Lamination Manufacturing: Our facility manufactures laminations from the "lamination up," ensuring motors are ideally suited for specific applications. We utilise low-loss lamination steel (3 Watts/kg) which allows higher flux densities with reduced heat generation and material weight.

Construction Philosophy: To ensure motor housing integrity, SME does not use castings—all components are machined from solid metal or extrusions. External aluminium components are typically 6061 T6 marine-grade aluminium, hard-anodised to military specifications. All hardware is 316 stainless steel, with all fixing holes blind except oil in/out fittings.

Winding Technology: Our superior Mylar-coated windings represent the ultimate in winding coating technology, with insulation ratings exceeding 16kV at temperatures to 140 degrees C. Winding wire for high-voltage motors is double-insulated and passes twisted wire testing at 16,000 volts, rated to 155 degrees C. All windings are designed to minimise turn-to-turn voltage, with materials and cables specially selected for operation in hydraulic oil.

Thermal Management: SME motors are designed to avoid overheating—typical motors can operate on deck for at least 10 minutes at full load without cooling. We offer heat exchanger motors (10-inch through 16-inch, 2-pole and 4-pole) providing significantly lower temperature rise compared with standard motors, extending operational life substantially.

Quality Components:

Ball bearings from SKF, FAG, or NSK
High-temperature Viton oil seals
Burgmann mechanical seals (single or double arrangements)
PT100 temperature sensors in windings and bearings
Water detection probes as standard
Subsea connectors (Subconn, Impulse, Burton) or oily tube power connections

Testing & Certification: All motors are pressure-tested to ensure oil-tight integrity for compensated operation to 4,000 metres. All motors are rated for continuous operation, with prototype motors undergoing full-load performance testing at rated voltage and frequency. Type Test Certificates are available, with full-load testing available upon request.

Enquire About Engineering Services

Submarine Thruster Systems

Silvercrest manufactures specialist submarine thruster motors with integral thrust bearing arrangements to handle propulsion loads in both directions. Unlike standard motors, thruster units are purpose-designed for voltage/speed control and incorporate thrust bearings to manage impeller loads.

Electric Thrusters for Manned Submarines

We supply AC thrusters as direct replacements for existing DC thrusters from 1kW to 50kW. Thruster motors feature reversible operation with robust shaft seals and bearings designed for continuous directional changes.

Typical Thruster Configurations

5.5kW, 4 Pole, 400/3/50, SS316 construction for steering and auxiliary propulsion
11kW submarine thruster motor (illustrated in source materials from submarine installations)
Custom designs with propellers mounted directly on motor shafts
Horizontal or vertical mounting arrangements

Thruster Design Features

Thruster motors incorporate integral thrust bearing assemblies, enabling direct propeller mounting whilst managing thrust loads effectively. Motor mounting arrangements and shaft requirements are customisable for specific submarine integration.

Enquire About Submarine Thrusters

Bespoke Subsea Motor Engineering & Custom Solutions

Silvercrest's flexible design capabilities enable custom motor manufacturing to suit virtually any submarine propulsion requirement:

Flexible External Dimensions: Motors can be designed to suit specific installation constraints, providing drop-in replacement capability for existing units or entirely new configurations for custom submarines.

Drive Configurations:

Single drive shaft with standard coupling
Close-coupled arrangements (eliminating coupling and housing weight)
Double shaft extension (drive shafts at both ends)
Female spline hubs for direct hydraulic pump fitment

Weight Optimisation: When weight is critical, motors can be designed for minimum weight utilising aluminium construction and hollow motor shafts whilst maintaining generous full-load operational ratings.

Voltage Flexibility: Custom voltage configurations from 24V to 6,600V (with specialist 10,000V units available) accommodate diverse electrical systems. Compatible with Variable Frequency Drives (VFD/VVVF) for speed control applications.

Interface Options: Motors can interface with various driven equipment including hydraulic pumps, water pumps, propellers, and specialised submarine systems. Shaft and flange specifications manufactured to precise customer requirements.

Enquire About Bespoke Subsea Motors

Global Manufacturing & Support Network

Submarine Motor Manufacturing Facilities

United Kingdom: Design, manufacturing, sales, service, and repair division
Australia: Primary manufacturing facility in Perth with 1,200 square feet workshop purpose-built for submersible motor manufacture
United States: Service and support facilities

Subsea Motor Service Capabilities

Silvercrest Submarines/SME operates comprehensive motor refurbishment and rewind programmes including strip-down inspection, cleaning, shaft seal replacement, bearing replacement, insulation testing, dynamometer testing, rewinding, and complete rebuild with despatch. Our service capability extends to all submarine motor manufacturers, often returning motors in better-than-new condition through implementation of latest engineering practices.

Subsea Motor Manufacturers Serviced

Alstra, Aturia, Bamsa, B.J., Elmaksan, Exodyne/EEMI, G.E., Hayward Tyler, Hitachi, Mercury, Oddesse, Pleuger, Saer, S.M.E., Subteck, Sumo, Sun Star, U.S.

Australian Facility Capabilities

New submersible motors (6" to 20", 5HP to 550HP, 2-pole and 4-pole)

All voltages and frequencies

Full machine shop capacity

Voltage testing through 10,000 volts

ISO 9001 quality-assured workshop

Overhead crane (10-tonne SWL)

Water pressure test facility with international certification

Full-load dynamometer testing to 250kW with detailed certification

Balancing facility to 250kg

High POT and surge testing

Enquire About Manufacturing & Support

Oil Compensation Units for Submarines

Silvercrest supplies oil compensator units for manned submarines, providing pressure compensation for oil-filled motor systems and other subsea equipment requiring compensation circuits.

Available Sizes:

270cc capacity compensators
2,700cc capacity compensators (2.7L)
13.5L capacity compensators

Specifications (2.7L Unit):

Rolling diaphragm positive pressure compensator
2,700cc (2.7 litre) capacity
Corrosion-resistant Delrin plastic construction
Grade 316 stainless steel spring
Adjustable pressure relief valve
Mounting feet included
Low-level proximity sensor option
7 x 1/4" NPT (BSPT) fittings

These compensator units are particularly suitable for submarine thruster systems, oil-filled junction boxes, valve packs, and other submarine applications requiring pressure compensation at operational depths.

Enquire About Oil Compensation Units

Why Choose Silvercrest Submarine Motors

Manufacturing Expertise: Complete vertical integration from lamination design through final testing ensures motors optimised for submarine applications rather than adapted from industrial designs.

Proven Performance: Motors operating in demanding submarine environments including tourist operations, research expeditions, filming platforms, and commercial diving support demonstrate real-world reliability.

British Engineering Quality: ISO 9001:2000 certification for design, development, manufacture, and testing ensures rigorous quality standards throughout production.

Comprehensive Support: Global service network with facilities in UK, Australia, and USA provides technical support, commissioning assistance, troubleshooting, and complete refurbishment services.

Custom Engineering Capability: In-house lamination manufacturing and flexible design capabilities enable bespoke solutions for unique submarine applications unavailable from standard motor suppliers.

Quality Components: Premium bearings (SKF, FAG, NSK), high-temperature seals (Viton, Burgmann), and military-specification anodising ensure long-term reliability in demanding marine environments.

Competitive Delivery: Bespoke orders regularly completed in 6-8 weeks from specification agreement, with emergency availability for critical submarine operations.

Technical Specifications & Standards

Depth Ratings:

Standard: 4,000 metres (oil-filled external compensation)
Specialist configurations: 6,000 metres and beyond
Testing: All motors pressure-tested to ensure oil-tight integrity

Operating Parameters:

Continuous operation rating
On-deck operation capability: minimum 10 minutes full-load without cooling
Temperature sensors: PT100 fitted in windings and bearings
Water detection: Standard water ingress detection probes
Monitoring: Temperature protection units (SME4TM) available for multi-sensor monitoring

Power Connections:

Preferred: "Oily tube" connected to oil-tight rubber gland fixed to stator frame
Alternative: Subsea connectors (Subconn, Impulse, Burton)
Rationale: Oily tube eliminates endshield complications during service strip-down

Thermal Protection:

Four PT100 sensors standard in heat exchanger motors
Sensor locations: thrust bearing, non-drive end winding, mid-motor winding, drive end winding
Temperature monitoring units alarm on abnormal temperature rise

Certification:

ISO 9001:2000: Design, development, manufacture, and testing of submersible electric motors
Type Test Certificates available
Full-load performance testing at rated voltage and frequency

Investment Considerations & Operational Economics

Long-Term Reliability: Mylar-coated windings with >16kV insulation rating at 140°C provide extended operational life. Heat exchanger models operate 25 degrees cooler than standard motors, significantly extending insulation life (industry rule: insulation life halves for every 10°C increase in operating temperature).

Maintenance & Serviceability: Horizontal-axis design with heavy-duty tapered roller bearings provides calculated bearing life exceeding 11,000 hours even under continuous load. Superior design extends service intervals compared with vertical down-hole motor designs adapted for horizontal submarine use.

Operational Efficiency: Low-loss lamination steel (3 Watts/kg) with higher flux densities reduces heat generation and improves electrical efficiency, lowering operational costs through reduced current draw.

Custom Engineering Value: Bespoke motor designs optimised for specific submarine installations eliminate oversizing common with off-the-shelf products, reducing initial investment and operational costs whilst improving performance.

Support Network Value: Global service capability with UK, Australian, and US facilities ensures rapid technical support and cost-effective refurbishment services, minimising operational downtime.

Frequently Asked Questions About Submarine Propulsion Systems

To prepare an accurate specification and quotation, Silvercrest Submarines requires the following details: the submarine application type (tourist, research, luxury, commercial, or military); power requirement in kilowatts or horsepower; supply voltage and frequency; preferred pole configuration (2-pole, 4-pole, 6-pole, or 8-pole); operational depth; preferred construction material (316 stainless steel, Super Duplex, or hard-anodised aluminium); shaft and flange interface requirements; and details of the driven equipment (propeller, hydraulic pump, gearbox, or water pump). The more detail provided at enquiry stage, the faster a precise specification can be developed. Contact our technical team via form to begin the consultation process.

Lead times depend on specification complexity and current production scheduling, but bespoke submarine propulsion motors are regularly completed in six to eight weeks from receipt of confirmed order and specification sign-off. As a reference point, Silvercrest Submarines manufactured and delivered ten 260kW submersible motors to a subsea operator in just six weeks from order. For urgent or emergency requirements, please discuss timescales directly with our technical team, as priority scheduling may be available for critical operational situations. Standard replacement motors and smaller thruster units may be available more quickly. Contact us to discuss your specific timeline requirements.

Yes. Silvercrest Submarines/SME offers direct replacement motors designed to fit many established submarine and ROV platforms, including Perry, Hydrovision, Slingsby, Sunn Star, and Fowler systems. Where an exact replacement is not available, SME's flexible external dimension design capability enables motors to be manufactured to match the mounting interfaces, shaft dimensions, and flange specifications of the unit being replaced — eliminating the need for costly submarine modifications. Motors can also be redesigned to suit different voltages or frequencies if the electrical system has been upgraded since original installation. Provide the existing motor's nameplate data and we will identify the most cost-effective replacement route.

All standard Silvercrest Submarines/SME motors are oil-filled and externally compensated for operational depths to 4,000 metres as a baseline specification. For deeper operations, specialist configurations are available: bespoke units have been manufactured and certified for 10,000 metre operations, as demonstrated by the 260kW motors supplied for subsea trenching operations at that depth rating. The appropriate depth specification is determined at the design stage and pressure-tested prior to delivery to confirm oil-tight integrity. If your submarine operates — or may operate — beyond standard depth parameters, discuss this during the initial specification consultation so that compensation systems and sealing arrangements can be designed accordingly.

Yes — Silvercrest Submarines/SME provides comprehensive repair, rewind, and refurbishment services for all major brands of submersible and subsea motor, regardless of manufacturer. Brands regularly serviced include Alstra, Aturia, Bamsa, Byron Jackson, Elmaksan, Exodyne/EEMI, GE, Grundfos, Hayward Tyler, Hitachi, Mercury, Oddesse, Pleuger, Saer, Subteck, Sumo, Sun Star, and Franklin. In many cases, motors can be returned in better-than-new condition through implementation of current engineering practices — including upgraded winding materials, improved sealing arrangements, and the addition of condition monitoring equipment not present in the original build. Contact us with motor nameplate data and fault description to obtain a service assessment.

Yes. Silvercrest Submarines has designed and installed complete propulsion system upgrades for existing manned submarines, including battery bus redesign, motor replacement, and drive controller matching. A key example is the installation of a 69kW AC propulsion and ballast system (comprising six 11.5kW thruster/ballast pump motors) into an Odyssey class tourist submarine operating in Southeast Asia. The system replaced an ageing DC drive arrangement and incorporated CT Commander SE invertor controllers with digital control and onboard fault diagnosis. If your submarine is operating with a propulsion system more than five years old, the drive controller capacitors may already be approaching the end of their serviceable life — a comprehensive assessment is advisable before failure occurs.

Silvercrest Submarines/SME motors are available across a wide voltage range to suit the electrical systems of different submarine platforms. Standard configurations cover 24V through to 6,600V AC at 50Hz or 60Hz. Motors up to 4,160V can be built with random wound stator windings, reducing size and weight whilst maintaining full reliability; above 4,160V, formed coil construction is used. All winding wire for high-voltage motors is double-insulated, passes twisted wire testing at 16,000 volts, and is rated to 155°C. Variable Frequency Drive (VFD/VVVF) compatible designs are available across the range. For tourist submarine applications, common configurations range from 340–480VAC for thruster systems through to higher voltages for main propulsion motors.

Next Steps for Submarine Operators

Silvercrest Submarines welcomes technical consultations with submarine operators, manufacturers, and marine engineering firms seeking propulsion solutions for new-build vessels, retrofit projects, or replacement motor requirements.

Technical Consultation Process

Initial Requirements Discussion: Power requirements, voltage specifications, operational depth, mounting constraints, and submarine integration requirements

Custom Specification Development: Detailed motor design incorporating shaft/flange requirements, interface specifications, sensor requirements, and testing protocols

Engineering Drawings & Approval: Technical drawings and specifications for customer review and approval

Manufacturing & Testing: Bespoke motor manufacture with full factory performance testing on dynamometer at rated voltage and frequency

Delivery & Support: Motor delivery with technical documentation, commissioning support available, and ongoing service network access

Information Required for Quotation

Submarine application (tourist, luxury, research, commercial)

Power requirements (kW/HP)

Voltage and frequency (VAC, Hz, phases)

Pole configuration (2-pole, 4-pole, 6-pole, 8-pole)

Operational depth requirement

Construction material preference (SS316, Super Duplex, Aluminium)

Shaft/flange interface requirements

Driven equipment details (propeller, pump, gearbox)

Pricing Strategy: All submarine motors are supplied on a Price on Application (POA) basis following technical specification agreement. This consultative approach ensures motors are optimally specified for operational requirements whilst qualifying serious submarine engineering projects.

Get In Touch