The Icebreaking Tug is Designed for Arctic and Sub-Arctic Ports, Delivering Superior Icebreaking, Ship Assist, and Escort Capabilities
Canadian naval architecture firm Robert Allan Ltd. announce a new contract, signed in November 2025 for the design of a TundRA 3100 icebreaking tug for the Port of Skellefteå, Sweden. As the newest member of the highly regarded TundRA series, the vessel is engineered to excel in the harsh conditions of Arctic and sub-Arctic ports, providing superior icebreaking, ship assist, and escort services.
With the TundRA 3100, the Port of Skellefteå will benefit from enhanced ice management capabilities, reduced winter downtime, and improved safety for vessels operating in icy waters. The tug’s advanced design and icebreaking performance make it an ideal choice for supporting the growth and resilience of northern ports that face challenging ice conditions.
The vessel will be equipped with innovative electrically driven azimuthing propulsors, an electrical battery energy storage and a diesel power generation plant. The flexibility offered by this electric powering system will let the tug perform some ship assistance operations on electrical battery power alone without engaging diesel engines. This will save fuel, cut emissions, and reduce maintenance costs.
The advanced RIM-Drive tunnel thruster will allow for heading control during buoy-tendering/fairway management duties.
Key TundRA 3100 Particulars:
- Length overall: 30.5 metres (excluding fenders)
- Breadth: 12.8 metres
- Draft navigational: 5.6 metres
- International gross tonnage: 495 (approx.)
- Accommodation: 6 persons
- Fuel oil: 110 m3
- Potable water: 10 m3
- Bollard pull: 60 tonnes minimum
- Icebreaking performance: breaks up to 1.0-metre-thick ice with speed of 2.5 knots
Innovative Design for Icebreaking Performance:
The compact (under 500 GT) TundRA 3100 is designed to break ice efficiently using a combination of a powerful and effective propulsion system and an advanced hull geometry methodically developed from previous Robert Allan Ltd. icebreaking designs. The hull geometry for the TundRA 3100 is well-proven from both extensive model testing and lessons learned from accumulated operational experience from previous TundRA vessels. Powerfully propelled by a pair of electrically driven contra-rotating propulsors, the tug can operate in challenging ice conditions to ensure safe and reliable port operations throughout the winter season.
Ice Testing and Ice Performance Validation Process:
Model-scale ice breaking testing played a crucial role in validating the icebreaking performance of the TundRA 3100. Testing was conducted at the National Research Council of Canada’s Ocean, Coastal and River Engineering Research Centre’s facilities in St. John’s, Newfoundland and Labrador, in July 2023, with valuable advisory services and financial support from the National Research Council of Canada Industrial Research Assistance Program.
A key question to answer was how ice performance was affected by the hull shape and interaction with propulsors. For the TundRA 3100, the hull shape was optimized for operation in the extreme climate conditions and ice-infested waters of the northern Gulf of Bothnia on the basis of previous experience, model tests, and feedback from operators.
Another goal was to verify and optimize the performance of the hull-propulsor system under icebreaking conditions. The TundRA 3100 is equipped with ice-capable azimuth propulsors with contra-rotating propellers. With two propellers per propulsor, the thrust is at least 10% greater than that produced by a single propeller Z-drive of the same diameter. This can make a significant difference in icebreaking performance.
The model tests results exceeded expectations. Tests confirmed that this relatively small 30.5 m long TundRA 3100 can break 1.0 m thick ice at a speed of 2.5 knots. When going astern, the TundRA 3100 can break 0.7 m thick ice at a speed of 2.0 knots. This level of the astern icebreaking performance is impressive for such a compact icebreaking vessel.
The success of the testing program was due in no small part to the excellent support provided by the National Research Council of Canada’s ice testing team.
The TundRA 3100 represents the continuation of Robert Allan Ltd.’s legacy in the icebreaking vessel design, supporting sustainable operations in some of the world’s most demanding environments. Robert Allan Ltd. remains committed to delivering innovative and reliable marine solutions worldwide.
