Water Ingress

ST SEAL
Stern Tube Water Ingress Control

The ST Seal range is designed to support stern tube systems affected by water ingress. Core, Plus, and Max are selected based on water ingress level, system condition, oil volume, seal arrangement, and operating profile.

System Compatibility & Blending

Our Water Ingress treatments are based on high-quality stern tube oil and are designed to blend with most commonly used stern tube lubricants. The product is added to the relevant oil system according to the recommended dosage and application guidance.

Suitable System Types

Water Ingress treatments can be considered for selected aft seal, forward seal, and stern tube applications, including common lip seal, face seal / Cedervall-type, and air seal arrangements.

The correct treatment approach is recommended based on water ingress level, oil volume, system condition, seal arrangement, lubricant condition, and operating profile.

Assessment Before Application

Before treatment, we review the seal type, water ingress level, oil type, viscosity, oil volume, filtration, system configuration, water contamination level, and operating conditions. This allows us to recommend the most suitable product, dosage, and onboard application approach for the specific case.

ST Seal Product Range

Water Ingress rates are indicative only. The final recommendation is based on a technical review of the system, seal arrangement, lubricant, oil volume, filtration, and operating conditions.

Application Example

Developed for real operating conditions across a wide range of vessel types and sealing systems.

Low-Level Leakage - Fishing Vessel

Vessel type: Fishing vessel
Stern tube volume: ~600 L
Observed issue: Low-to-moderate water contamination in the stern tube oil

Scenario

During regular fishing operations, the crew observed signs of water contamination in the stern tube lubrication oil. The oil condition had gradually changed over time, with increased cloudiness and indications of water ingress during routine checks. While the vessel remained operational, the operator wanted to reduce further water contamination and support stable seal performance until planned maintenance.

Action

The operator contacted Addvation to assess the situation. Based on system volume, oil condition, operating profile, and observed water ingress, a water ingress treatment was recommended.

Recommended starting point: ST Seal Core
Indicative quantity: ~40 L total

Application

The product was applied by the crew during a routine port stay, following the recommended application guidance and monitoring procedures.

Outcome

Water ingress was reduced and brought under better control. The oil condition stabilized, and the vessel was able to continue operation while the system was monitored toward the next planned maintenance window.

Moderate Leakage - Harbour Tug

Application Scenario
Water Ingress – ST Seal Plus for a Harbour Tug

Vessel type: Harbour tug
Stern tube volume: ~450 L
Observed issue: Water contamination in stern tube oil

Scenario
During harbour operations, the crew observed increasing cloudiness in the stern tube oil during routine checks. The tug was operating with frequent manoeuvring, high load changes, and repeated low-speed operation, creating demanding conditions around the seal system.

Action
Based on the oil condition, system volume, operating profile, and observed water ingress, ST Seal Plus was recommended as a targeted water ingress treatment.

Recommended starting point: ST Seal Plus
Indicative quantity: ~25–35 L total

Application
The product was applied during a scheduled service window in port, following the recommended dosage and onboard monitoring guidance.

Outcome
Water ingress was reduced and brought under better control. The oil condition stabilized, allowing the tug to continue operation while the system was monitored toward planned maintenance.

High Leakage - Trailing Suction Dredger

Application Scenario
Water Ingress – ST Seal Max for a Dredger

Vessel type: Trailing suction hopper dredger
Stern tube volume: ~1,800 L
Observed issue: High water contamination in stern tube oil

Scenario
During dredging operations in shallow and sediment-heavy waters, the crew observed a clear deterioration in stern tube oil condition. Routine inspections showed increased water contamination, with the oil becoming cloudy and unstable under demanding operating conditions.

Action
The operator contacted Addvation to assess the situation. Due to the harsh operating environment, system size, and water contamination level, a stronger water ingress support approach was recommended.

Recommended starting point: ST Seal Max
Indicative quantity: ~120–150 L total

Application
The product was applied during a planned port stay, following the recommended application guidance and monitoring procedures.

Outcome
Water ingress was reduced and the oil condition became more stable. The vessel was able to continue operation while the system was monitored until the next planned maintenance opportunity.