GMI Shipsurveyor 1 Marine Tankscope Gas Detector

GMI Shipsurveyor 1 (S-1) Marine Portable Gas Detector (LEL / VOL)

The GMI Shipsurveyor 1 (Model S-1 / MPN 48021) is a dual-mode marine portable gas detector engineered specifically for crude oil tankers, chemical carriers, LNG/LPG vessels, and offshore terminals. Unlike standard catalytic bead monitors that fail in nitrogen-purged or oxygen-depleted environments, the Shipsurveyor 1 utilizes advanced non-dispersive infrared (NDIR) dual-sensor technology. This allows precise hydrocarbon vapor measurements across both Lower Explosive Limit (0–100% LEL) and volume concentrations (0–100% Volume Gas) inside totally inert cargo tank atmospheres.

Designed to meet strict international maritime safety mandates (SOLAS Reg. XI-1/7 and MED Directive), the unit functions seamlessly as both a Combustible Gas Indicator (CGI) for inerting, purging, and gas-freeing operations (Tankscope function), and as a Confined Space Monitor (CSM) for personal protection during pre-entry checks in ballast tanks, cofferdams, pump rooms, and double hulls.

Technical Details

Features

1. Infrared (NDIR) Sensor Technology: Measures 0–100% LEL and 0–100% Volume hydrocarbons accurately without requiring oxygen, preventing sensor poisoning or false zero readings common with pellistor sensors during nitrogen inerting.
2. Integrated High-Vacuum Sampling Pump: Delivers an uninterrupted suction draw capable of pulling samples through conductive sample lines up to 30 meters, equipped with rapid flow-fail sensor protection against line blockages.
3. Dual-Mode Operation (CGI & CSM): Switch between Combustible Gas Indicator (CGI) mode for tanker cargo piping and inert tank testing, and Confined Space Monitor (CSM) mode featuring latching audible/visual alarms for personnel tank entry.
4. Vessel Location Tagging (LOC Selector): On-board datalogger stores up to 300 vessel-specific compartment names (e.g., Cargo Tank 1P, Forepeak, Pump Room Bilge), matching logged records to exact ship locations for audit-compliant record keeping.
5. Rugged Anti-Static Construction: Built in an anti-static carbon-impregnated polypropylene enclosure rated to IP54, purpose-built to withstand mechanical shocks, saline maritime exposure, and harsh deck conditions.

Applications

• Inert Cargo Tank Monitoring (Tankscope): Hydrocarbon concentration measurement during nitrogen/flue gas inerting, purging, and gas-freeing stages on crude oil, product, and chemical tankers.
• Pre-Entry Confined Space Testing: Enclosed space entry clearance verification for ballast tanks, double bottoms, cofferdams, chain lockers, duct keels, and cargo compressor rooms under IMO Resolution A.1050(27).
• Cargo Piping & Manifold Leak Detection: Sniffing and locating fugitive hydrocarbon leaks around cargo pump mechanical seals, manifold blind flanges, pressure relief valves (P/V valves), and deck expansion joints.
• Post-Discharge Tank Atmosphere Verification: Monitoring hydrocarbon vapor evacuation progress during mechanical ventilation cycles before drydocking or hot-work repair operations.
• Terminal & Jetty Transfer Safety Checks: Verifying vapor recovery lines, barge loading manifolds, and shore-to-ship connection safety zones.

Compatibility

• Calibration Test Systems: Fully compatible with the GMI Auto Calibration Station / GDUnet (Part No. 14750) and manual bump test kits utilizing certified Methane / Propane span gas cylinders.
• Software Interfaces: Fully supported by GMI FlexiCal Plus calibration software and Shipsurveyor Data Downloading software via the instrument’s optical IrDA link.
• Sample System Accessories: Compatible with standard GMI quick-connect sample handles, hydrophobic water traps, and conductive sampling hoses (10 m, 25 m, and 35 m lengths).

Part Number Cross-References & Equivalent Options

• 48021: GMI Shipsurveyor 1 (S-1) – LEL / Volume Gas (Infrared)
• 48022: GMI Shipsurveyor 2 (S-2) – LEL / Volume Gas / O₂
• 48023: GMI Shipsurveyor 3 (S-3) – LEL / Volume Gas / O₂ / H₂S
• 48100: GMI Heavy-Duty Protective Hard Carrying Case
• 48120: Quick-Connect Probe Handle with 1-Meter Conductive Line
• 12358: External Hydrophobic Filter Assembly
• 10077: Box of 10 In-Line Cotton Dust Filters
• Direct Industry Equivalents: Riken Keiki RX-8000 / RX-8500 (Tanker Version), Crowcon Triple Plus+ IR (Inert Tankscope), Dräger X-am 5600 IR Dual Gas.

Frequently Asked Questions

Can the Shipsurveyor 1 measure gas in inert or oxygen-depleted atmospheres?

Yes. The instrument uses dual-wavelength infrared (NDIR) absorption technology. Unlike catalytic bead detectors that require atmospheric oxygen to combust and register flammable gas, infrared sensors operate independently of oxygen concentrations, providing reliable measurements inside nitrogen-purged cargo holds or inert gas atmospheres.

How does the dual-mode operation switch between CGI and CSM?

The Shipsurveyor features two user-selectable operating modes:

• Combustible Gas Indicator (CGI): Designed for active tank sampling, purging, and leak sniffing. Auditory gas concentration alarms are muted to avoid nuisance trips while monitoring high-volume vapors, though safety fault alerts remain active.
• Confined Space Monitor (CSM): Configured for personal entry safety with high-decibel audible (>85 dB) and visual LED alarms that latch when hydrocarbons exceed programmed LEL safety thresholds.

What is the maximum sampling line length for remote tank sampling?

The internal high-vacuum rotary pump is engineered to draw samples through antistatic tubing up to 30 meters (approximately 98 feet) with an integrated flow-rate monitoring circuit that immediately triggers an alert if the probe or line becomes blocked or pinched.

What type of batteries does the GMI Shipsurveyor 1 use?

The instrument is powered by two commercial LR20 / ‘D’ size alkaline cells, providing approximately 20 hours of continuous operational runtime. It can also be powered by certified rechargeable ‘D’ battery packs, which offer around 8 hours of continuous runtime per charge. Battery replacement must always be carried out in an identified gas-free safe zone.