Over 125 Years Of Service

L.L. Rowe manufactures to Navsea and Bureau of Ships drawings, as well as the latest Military Standards and Mil Specs including a full line of  Pressure Proof Electrical Hull Fittings.  Many of the Products that we manufacture are found in the U.S. Navy Standard Electrical Symbol List (Navsea Publication S0300-AT-GTP-010/ESL).

The company consists of two divisions, the Submarine Division and the Surface Ship Division, both of which will custom manufacture products from one to many thousands.

Whatever your needs, Electrical Connectors, Molded Cable Assemblies, Hull Penetrators, Magnetic Switches, Distribution Panels, Control Boxes, Navigational Lighting, Interior Communication Equipment, the L. L. Rowe Co. and it’s expert staff will work with you to develop a quality product.

L.L. Rowe – Integrated Solutions for Submarines and Surface Ships

Quality Requirements

DoD Security Document



L.L. Rowe Company
15 Gray Lane, Suite 108,
Hopkinton Industrial Park,
Ashaway, RI 02804, USA.

TEL: +1 (401) 637-4952
FAX: +1 (401) 637-4953



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Hull Connectors


L.L. Rowe has supplied single and multiple hull connectors and multi-pin receptacles for virtually every class of U.S. submarine built in the 30 years.  Connector bodies are machined under computer control from chemically and physically certified Monel 500 (per QQ-N-286 class A) bar stock.  After  age hardening, connectors undergo  welding and nondestructive testing.  Symbol 516 Multiple  Hull Connectors are made to customer specifications for size and receptacle configuration.  Symbol 737 Receptacles can carry from 3 to 40 conductors depending on the type of wire and epoxy insert chosen.  L.L. Rowe is the qualified source for any MIL-C-24231 requirement.



Multiple Hull Connectors

 Single Hull Connectors

Miltary Spec: MIL-C-24231/5 thru /11

Electric Boat Specs:

  • CPG1025/1
  • CPG1022
  • EB2982
  • EB3004

All connectors are hydrostatically tested to 2,000 psi in L.L.Rowe’s 250 gallon ‘Hydrotank’ in full compliance to military specifications.

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infrared approach signal192

Infrared Transmitter

Approach Light Symbol 164.3

Signal Light Symbol 192.1

navred navclear navamber navblue

Submarine Navigational Lights for Port, Starboard and Masthead,
SYM 174, 188 and 189 Series

subid warning sight

SUB ID Light SYM 177

Aircraft Warning Symbol 160.1

Sight Light Symbol 136/156

signal lantern flood
Symbol 190 Series Signal Lights SYM 100, 101, 102 & 103 Series Hand Lanterns

Symbol 303 Series Flood Lights


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gptp ic-1 fuse-1
Symbol 2457 General Purpose Test Panel Symbol 2840 Shipboard Communication Testing

Symbol 600 Series Fused Feeder Distribution Panel


dimmer pbcu starter-1
Symbol 989.1 Dimmer Control Panel Symbol 2945 Portable Bridge Control Panel

Symbol 815/816 Motor Starter Control Panel


emergency telltale monel_box_new
Symbol 2470.2 Emergency Switch Panel Symbol 969 Power Distribution Panel

Connectorized Box Vertical launch System New Generation 


supplcontr blank-box-hx150 blank-box-hx150
Symbol 940.1 Supply and Control Panel

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Plugs and Receptacles Per MIL-C-24231, Different Configuration,

Available from Stock




Glass Seal Headers, Pressure Proof for Different Submarine Hull Penetrators




Connectors Per MIL-C-24217

Connectors Per navy Drawings 1197351

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Cable Assemblies and Molded Products


L.L. Rowe manufactures a full line of MIL-C-24231 pressure-proof electrical fittings.  Cable assemblies are made to customer specifications for cable type, length, number of conductors, and plug style.  Each completed assembly is tested to prove its electrical performance and its ability to withstand up to 2,000 lbs./sq. in hydrostatic pressure.



SYM 713 (Series) Cables and Special Purpose Cables

Shore Power Insert




Cable Assembly and Plug for Submarine Secondary Propulsion Motor,
440 Volts, 600 amps, 60 HZ




Receptacle Outlet Symbol 779

Molded Inserts Per MIL-C-24231
All Configurations,
Available from Stock



High Voltage Shorting Cables for Large Batteries

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Proximity Switches


L.L. Rowe manufactures a variety of pressure-proof Magnetic Switches such as the Symbol 2742 and 2744.  These are commonly used to indicate mast and antenna position.  Housings are available in monel, molded polyurethane, or glass-filled epoxy resin.



Submarine Magnetic Switch, Symbol 2744

Submarine Magnetic Switch, Symbol 2742



Submarine Magnetic Switch, Symbol 2652.1

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Electrode, Snorkel Symbol 3007

Electrode, Snorkel New Generation




Electrode Sensors for Submarine Use,
Symbol 3012

Electriode, Special Purpose

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Whatever your needs, Electrical Connectors, Molded Cable Assemblies, Hull Penetrators, Magnetic Switches, Distribution Panels, Control Boxes, Navigational Lighting, Interior Communication Equipment, the L.L. Rowe Co. and its expert staff will work with you to develop a quality product.

Whatever the size of the run, our sales staff and our project engineers will work closely with you to develop a product of unfailing quality.


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All our work is performed to the highest level of dependability.  Our quality control personnel exceed, as a matter of policy, the requirements of the MIL-I-45208 Inspection System.

Electrical Testing

  • Insulation resistance to 1,000,000Ω (1 Megohm)
  • High potential to 5000 Volts
  • Continuity check
  • All electrical testing can be performed during hydrostatic pressure testing

johnmagTesting a Magnetic Reed Switch

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Mechanical Inspection and Testing


Below  listed are some of our  capabilities;

  • Material Certification
  • Concentricity
  • Parallelism
  • Perpendicularity
  • Run out
  • Micro finish
  • True Positioning
  • Dye Penetrant

measureChecking dimensions of a Submarine Hull Penetrator

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Hydrostatic Testing


All Penetrator Hydrostatic Testing in Accordance with:

Los Angles Class Ohio Class SeaWolf Class Virginia Class
MIL-C-24231/5 thru 11 CPG1022 PSSSN21C-305 EB4210
EB3004 CPG1025 EB4211
EB3648 CPG1027 EB4212
EB2982 EB3851 NAVSEA DWG #7491201


tonyhydroInserting a MIL-C-24231 Hull Body

Hydrostatic Test Tank  Specifications:

  • Fully Automated / Variable timed data logging (Pressure vs. Time)
  • 1% Accurate Transducer – Output to MS Excel Spreadsheets
  • 2000 psi – regulated to your requirements
  • 30 inch internal diameter
  • 66 inch depth
  • 150 gallon, 6,200 cubic inch capacity
  • 4 – 4″ diameter internal penetrations


Data Logging:

A typical Pressure VS Time graph from a EB 3004 Specification Test derived in MS Excel

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Environmental Testing


All Environmental Testing is at a minimum is accomplished in accordance with MIL-STD-810.

HALT (Highly Accelerated Life Testing) is performed on a product as part of the design process. Typically it is performed an a product when pre-pilot or pilot run units are available, before the design verification begins. During a HALT, a product is stressed far beyond what the product will encounter in a typical use environment. The actual functional and destruct limits of the product are found and pushed out as far as possible. These limits are used as the basis for the implementation of the HASS (Highly Accelerated Stress Screening) process during normal production of the product. HASS is a production screening test, performed on products built as part of the production process. The goal of HASS is to catch production run induced errors and weak link components that would otherwise fail in the field, thereby quickly weeding them out and fixing them prior to release to the customer.

Chamber Specifications:

  • Temperature Range: -100ºC to +200ºC
  • Vibration: 30Grms at 10khz – 6 Axis (3 Linear / 3 Rotational)
  • Remote Actuation via Pneumatics
  • Variable Timed Data Logging: Chamber Internal / Exterior National Instruments Data Acquisition System






Chamber Setup for a SELS Burn-In

Chamber Setup for a SELS H.A.S.S.


Data Logging:


2 Screens associated with H.A.S.S. Test: 

Top – National Instruments / LABVIEW Data Acquisition Screen.

Bottom – Chamber Control Screen

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To ensure reliability, L.L. Rowe has a broad range of highly sophisticated manufacturing capabilities including:


Mechanical and electrical (wiring)



Assembly of a Photonics Mast Penetrator

Assembly of a General Purpose Test Panel


Precision machining of high-tech alloys


Machining a MIL-C-24231 Hull Body

Welding and Brazing


Welding a magnetic reed switch frame


Polyurethane, silicone, epoxy, neoprene


Back-filling magnetic reed tubes

Quality Control

We can trace all materials we manufacture to “SubSafe” and “Level One” requirements


Back-filling magnetic reed tubes

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Innovative and experienced product engineers are available to assist you with special requirements.  We will custom manufacture product you require in quantities from one to many thousand.

Below are the samples of some of the products  that L.L. Rowe engineers developed for our customers.



Water Sensing Heated Electrode


This is a new fully automatic generation of  heated electrode originally designed to NavSea Dwg 1197032, Symbol 3007-3010. This electrode ensures closure of the snorkel head valve and main induction valve during submergence.

  • Automatic Heating from 2 to 21 Deg. C
  • Solid-state Temperature Controller
  • Relay output to 200 milliAmp
  • 120 VAC/60 HZ input
  • Operating Range  -40 to 66 Deg. C
Development Includes:
  • Shock Testing (Wetted Surface)
  • Vibration Testing (to 25 Hz)
  • Pressure Testing (to 2000 psi)
  • Temperature Testing (-55 to 71 Deg. C)

Custom Applications are Available – Call for More Information


Submersible Electronic Limit Switch (SELS)


The Submersible Electronic Limit Switch (SELS) was developed by L.L.Rowe and Electric Boat for US Navy VIRGINIA Class submarine outboard launcher and weapons systems applications. The SELS provides precise, repeatable and reliable position sensing in the extreme sub-sea environment. Additional systems and classes of ships also use the SELS. The SELS is fully qualified to VA Class military requirements.

The SELS is a connectorized, stainless steel, hermetically sealed, pressure-proof cube approximately 3.5” on a side. The major components internal to the SELS are linear variable differential transformers (LVDT) and the interfacing LVDT signal conditioning printed circuit board (PCB).  The SELS has two independent channels capable of monitoring two separate actions, or to provide redundancy for a single action. Position sensing is provided from either of two cube faces. The SELS uses an LVDT in concert with interfacing circuitry for each channel to sense the proximity of an external ferrous pellet. The ferrous pellet is encased in a stainless steel probe for strength, a means of attachment, and to prevent corrosion. In most cases, the probe is attached to the component whose position is being monitored. The SELS can also be attached to the moving component while the probe remains stationary. Each channel of the SELS provides a SPST contact closure for position sensing. In addition, a single tell-tale signal, derived from both channel relays in series with the excitation power is provided.



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Copyright ©  1997-2004  L. L. Rowe Company. All rights reserved.