Why Underwater Inspections Matter

Mozambique’s marine and inland water assets operate in demanding conditions: low visibility, sediment, marine growth, restricted access, variable currents, port schedule pressure and site-specific safety constraints.

Underwater inspections are essential for:

• Maintaining vessel hull and running gear condition
• Supporting class, insurance, owner and technical manager review
• Monitoring marine growth, coating condition and fuel-performance impact
• Detecting visible damage, obstruction, debris, deformation or structural anomalies
• Providing evidence for post-cleaning verification and invoice approval
• Reviewing dam intakes, trash racks, water tanks and industrial water assets where safe access is limited
• Creating time-stamped visual records for engineering, operational or maintenance decisions

Main Types of Underwater Inspections

1. Hull Condition Survey

Visual documentation of hull plating, coating condition, marine growth, anodes, appendages, sea chests and visible anomalies.

2. Propeller & Rudder Inspection

Close-range imaging of propellers, rudders, nozzles and running gear to document impact damage, deformation, cavitation marks, rope/net contact or other visible defects.

3. Mini-ROV Inspections

Compact ROV systems are useful in low-visibility, restricted-access or higher-risk areas where diver exposure should be reduced or where a quick visual record is required.

4. Dam Intake, Trash Rack & Industrial Water Asset Inspection

Mini-ROV visual inspection can support dam intakes, trash racks, reservoir walls, water tanks, pump stations, intake screens and other submerged industrial infrastructure.

5. Class IWS Preparation Support

Owner-focused underwater checks, imagery and reporting packages to help prepare for class IWS, drydock or follow-up inspection planning. This is preparation support and does not replace class approval.

6. Biofouling Inspection

Structured marine growth assessment using underwater imaging workflows to support cleaning decisions, fuel-efficiency review, CII discussions and post-cleaning verification.

Biofouling Levels Explained

• Level 0 – Clean: Fresh paint or very recent cleaning.
• Level 1 – Light: Thin slime layer or very light growth, normally with limited drag impact.
• Level 2 – Moderate: Soft algae, slime build-up and patchy barnacles on selected areas.
• Level 3 – Heavy: Dense barnacles, tubeworms or heavy marine growth with likely drag and performance impact.

Mini-ROV Inspection for Hydro & Industrial Water Assets

In addition to vessel and port work, Inhaca Sub supports selected hydro and industrial underwater inspection scopes using compact Mini-ROV systems. This is useful where the asset is submerged, difficult to access, deep, confined or unsuitable for unnecessary diver exposure.

How Vessels Should Prepare for Inspections

• Share GA drawings, shell expansion, sea chest arrangement or relevant plans when available.
• Confirm port schedule, anchorage/berth position, tides and operational windows in advance.
• Ensure engines, thrusters and propellers remain fully stopped and secured during inspection.
• Stabilise the vessel as much as possible during inspection.
• Pause discharges, ballast activity or operations that may affect visibility or safety.
• Provide safe access, ladder arrangement and crew assistance where required.
• Display required signals/flags where applicable and comply with port authority instructions.

How Dam / Industrial Sites Should Prepare for Mini-ROV Inspection

• Provide final drawings, asset references, elevations, no-go areas and priority inspection zones where available.
• Confirm access point, deployment location, work platform and edge protection requirements.
• Confirm power supply, cable routing, safe working area and site communication channels.
• Confirm any shutdown, isolation, permit-to-work, LOTO or operational restrictions before deployment.
• Advise expected depth, visibility, current, flow, debris and known entanglement hazards.
• Nominate a site representative for live coordination, safety confirmation and close-out.

360° Virtual Vessel Tours for Crew Training & Simulation

Inhaca Sub can create interactive 360° virtual tours of vessels above the waterline — similar to real estate virtual tours, but adapted for shipboard operations, crew familiarisation and simple training scenarios.

Using 360° cameras, we can capture key areas such as the bridge, engine control room, accommodation, main deck, mooring stations, lifeboat stations and escape routes. The result is a browser-based tour that crews can explore on any laptop or tablet.

Typical Areas Covered

• Bridge, chart area and navigation workstations
• Engine control room and access routes to machinery spaces
• Main deck walk-arounds, manifolds and cargo control areas where applicable
• Forward and aft mooring stations
• Muster stations, lifeboats, rafts and embarkation areas
• Accommodation corridors, stairways and escape routes
• Gangway, access control points and visitors’ routes

How Operators Use the Tours

• Pre-joining familiarisation for new crew and riding squads
• Port and terminal specific safety briefings before first call
• Internal drills and scenario-based training using the real vessel layout
• Induction for shore-based superintendents, vetting and HSE personnel

Deliverables: a web-based 360° tour that runs in a standard browser, with hotspots and labels for critical equipment, routes and risk areas, ready for briefings, toolbox talks and internal training platforms.

Mini-ROV Ballast Tank Inspection via Deck Access

Inhaca Sub can perform internal ballast tank visual inspections using compact ROVs introduced from deck manholes and access hatches while the vessel is afloat, subject to tank condition, access, safety review and operational feasibility.

The Mini-ROV carries lighting and camera systems to document coating condition, corrosion indications, structural details, anodes and sediment inside tanks. This can reduce the need for initial man entry and provides visual evidence that owners, managers and class can review remotely.

What We Assess Inside Tanks

• Coating breakdown, blistering and rust staining on shell and internal structure
• Pitting, general corrosion indications and areas of possible wastage
• Stiffeners, webs, brackets and critical structural intersections
• Anode condition, wasted or missing anodes and areas with poor protection
• Sediment, scale and debris around suctions, drains and low points
• Evidence of previous repairs, reinforcements or crack-stopping works

Key Advantages for Owners & Managers

• Reduced initial confined space entry and associated risk
• Faster mobilisation using compact ROVs from deck access points
• Time-stamped video and stills that can be replayed, shared and archived
• Practical pre-screen before committing to full tank entry campaigns

Where We Operate

Inhaca Sub is based in Pemba, Mozambique. We support selected vessel, port, hydro and industrial underwater inspection scopes subject to access, permits, mobilisation, HSE requirements and operational feasibility.

• Pemba and nearby marine operations
• Palma and selected northern Mozambique operations subject to approvals and logistics
• Nacala, Beira, Quelimane, Moma, Maputo and Matola subject to scope, permits and mobilisation feasibility
• Selected inland hydro and industrial water assets in Mozambique where access and planning are feasible