Brunvoll Thruster
Spare Parts Supplier
Tunnel, retractable and propulsion azimuth thrusters from Molde, identified by the type letters on the plate and the control generation in the cabinet, then quoted by OEM route or verified alternative.
Brunvoll thruster families and the letters that mark them
Brunvoll goes back to 1912 and a works building engines and controllable pitch propellers for fishing vessels; the move to Molde came in 1918, and thrusters followed in 1964, when local fishermen asked for tunnel thrusters on a new vessel. The maker's tables group the thrusters under letters that mostly separate the families, and those letters, copied from the plate together with the digits after them, are where identification starts.
FU
The standard bow and stern tunnel unit, built with a controllable pitch or a fixed pitch propeller and in L-drive or Z-drive form. The electric motor stands on a bed frame on the thruster, upright or tilted, or on a separate foundation with a vertical intermediate shaft. The maker designs the gearbox to come out of the tunnel with the propeller blades left in place, fits replaceable blade bearing liners and seals the propeller shaft with a multiple sealing system. A trunk-mounted version sits in a trunk with a bolted tank top plate and can be lifted out for repair without dry-docking.
FW … R · LowNoise FU
Two quieter types sit beside the standard one. The Resiliently Well-mounted Tunnel Thruster carries FW designations ending in R, bolts into its well and is built to be serviced without dry-docking. The LowNoise Tunnel Thruster is resiliently mounted in a full-length double tunnel, leaves the factory complete and turns a CP propeller with skewed blades in one direction only; the maker dates its first low-noise thruster to 1977. LowNoise units are tabulated under the same FU letters as the standard tunnel thruster, so the double tunnel, not the designation, tells them apart. Where noise is measured in the thruster room, the sound level calculator subtracts the background from a reading and adds the levels of several sources.
RDT
The RDT puts a permanent magnet motor and the propeller into one unit, with no external motor, shafts or couplings, and is fed from a variable frequency drive. Units are built shaftless on water-lubricated bearings, with a central shaft on the larger sizes, and the maker states that the bearing design needs no oil lubrication. With no gearbox, most of the lines that fill a conventional thruster request do not exist here; the motor and the drive do.
AR
The retractable unit is a long vertical column with the electric motor on top, lowered and raised by hydraulically operated lifting equipment, held in the hull by spring-loaded locking devices and closed underneath by a flush plate on the bottom of the nozzle. Lowered but not turning, it is held in azimuth by mechanical brakes, and the stem passes through a combined sealing box and bearing housing on the tank top integration plate. The Combi works on the same principle with a nozzle designed to fit the hull tunnel: retracted, it acts as a tunnel thruster; lowered, as an azimuth. Both carry AR designations, so say which one is fitted.
AUP/AWP · PU
The propulsion azimuths carry AUP/AWP designations with a push ducted propeller and PU designations with a pulling open propeller. Both come in L- or Z-drive, with CP or FP propellers, welded in or bolted into a well, and the bolt-in arrangement lets the complete unit be lifted out of the ship without dry-docking. Ducted units are offered with a choice of nozzle profiles, among them the maker's own HE and DL1; pull-open units can have full feathering on CP propellers and an electrical steering gear with variable speed drive.
BruCon · Saia PCD
The control system is identified from the cabinet, not from the thruster plate, and since 2017 three control lines belong to one group: Brunvoll's own BruCon systems with the Saia PLCs behind them; the Volda line, from the VERC system on Siemens Simatic S5 to CPP@Control on S7; and the Mar-El line from Dalen, with Marco joystick systems and the Neptune and Triton families. Each is quoted from its own panel and controller.
Oil where it should not be, and a cabinet that has outlived its spares
Three questions decide most Brunvoll thruster requests, and only one of them can be read from the thruster plate.
The propeller shaft turns behind a multiple sealing system and the CP hub carries the blade seals; these are the places where oil meets the sea, and they are also where Brunvoll's EAL conversion works. Written for the US Vessel General Permit, it is a split system: environmentally acceptable lubricant only at the oil-to-sea interfaces, meaning the hub with its blade seals and the propeller shaft main seal, and ordinary mineral oil kept in the gearbox behind static seals, so that at least two barriers separate the gear oil from the sea. The maker says the conversion modifies both the thruster and its operating systems and includes a general upgrade of the pitch mechanism. A seal enquiry that does not say whether the unit was converted leaves open which arrangement is meant.
Whether parts are wanted for a docking or for a lift depends on how the unit is mounted rather than on its family. The maker designs trunk-mounted tunnel units, the resiliently well-mounted type and bolt-in propulsion azimuths to come out of the ship without dry-docking, offers retractable units with options for service afloat, and makes the blades of retractable and ducted azimuths replaceable inside the nozzle. Otherwise its service guidance is to schedule work in line with planned dockings and with the intervals in the instruction manual, and the parts are ordered for that window.
The third question sits in the cabinets. Brunvoll's control history starts with stand-alone cabinets and a 'frying pan' thrust lever, delivered from 1965 to 1980 and still in operation, continues with a second generation known as '631' after its controller card versions and a 'Black Box' controller for the retractable azimuth, and moves to PLCs from 1990: Saia PCD2 and PCD4 until about 2009, then BruCon 3 on Saia PCD3, BruCon 4 in the 2010s and BruCon 5, now the maker's standard for new projects. The maker states that PCD2 and PCD4 have been obsolete at Saia for some time and that it can no longer promise spare parts for them, and recommends an upgrade: a conversion kit that puts a PCD3 into the existing cabinet without new wiring, panels, sensors or pitch feedback, new PCD3 cabinets with encoder-type pitch feedback, or BruCon 5.
What gets ordered against a Brunvoll thruster
Grouped as the unit comes apart: the underwater end, gearbox and hydraulics, the drive, the retractable and azimuth mechanisms, then control. Seal and bearing lines are quoted against the designation, the serial number and the oil arrangement actually in use; neighbouring lines sit on seals, gaskets and bearings and electrical and control components.
- Propeller shaft seal rings and complete multiple-seal sets, for mineral oil or the split EAL arrangement
- Blade seals and hub sealing parts on controllable pitch propellers
- Replaceable propeller blade bearing liners
- Propeller blades and blade fixing parts, including re-blading sets
- Pitch mechanism parts and servo oil pipe seals
- Hydraulic power unit pumps, valves and filter elements
- Header and gravity tank fittings, level indicators and oil level switches
- Gearbox bearings, gear sets and static housing seals, quoted against the drawing
- Couplings and intermediate shaft parts where the motor stands on a separate foundation
- Electric motor bearings and terminal box parts
- Starter parts: contactors, soft starter and frequency drive components, read from the starter's own plate
- Lifting and lowering actuator seals, spring-loaded locking devices and azimuth brake parts on retractable units
- Parts of the combined sealing box and bearing housing on retractable azimuths
- Shaft brake parts on propulsion azimuths, where the project specified them
- Tunnel protection grids and anodes
- Control cabinet items: Saia PLC modules, power supplies, bridge levers, indicators, push buttons and lamps
- Pitch feedback units, both the older type and the encoder type
- Condition monitoring sensors where fitted, including oil quality sensors and particle counters
The plate on the thruster, and the cabinet that drives it
A Brunvoll request is answered from two places: the plate on the unit and the controller in its cabinet, and the numbers on both carry more weight than any description. Photograph the plate, the open cabinet and the leak or part in place; the RFQ evidence guide lists what else to attach.
- Type designation exactly as stamped, letters and digits together, with any suffix such as the R on a resiliently mounted unit
- Serial or order number from the same plate, under whatever heading the plate gives it
- Position on board, bow or stern, and how many units of that type the ship carries
- Controllable or fixed pitch, L-drive or Z-drive, and whether the motor sits on the thruster or on its own foundation with an intermediate shaft
- Mounting: welded tunnel, trunk, resilient well mounting, LowNoise double tunnel, retractable, Combi, or a weld-in or bolt-in azimuth
- Oil arrangement: mineral oil throughout or the split EAL system, and when the conversion was carried out
- Control generation as seen in the open cabinet: the BruCon version, or the Saia PLC type printed on the controller
- Starter or frequency drive type, taken from its own plate in the starter cabinet or switchboard
- The name on any gearbox, propeller or bridge panel plate in the same system: Brunvoll, Volda or Mar-El, with or without Scana
- Vessel name and IMO number, class society and the next planned docking, with drawing and item numbers where the instruction manual is aboard
Tools for this equipment: the lubricant code reader for the gear and hydraulic oils, the oil cleanliness code reader for an oil analysis report and the hose assembly builder for the hydraulic hoses.
A seal set, a filter and an obsolete PLC are three different questions
Thruster requests arrive mixed, and the lines in them are not answered alike. Vessel Core is an independent spare parts supplier and states the proposed route against each line.
The underwater end stays on the OEM route
Shaft seals, blade seals, blade bearing liners and pitch mechanism parts are changed as one job, in dock or with the unit lifted out where the mounting allows, and on a unit converted to split EAL they must match the conversion. These lines are reviewed on the OEM route, with the reference the request was checked against stated, and an unknown conversion status is flagged.
Measurable items can be cross-checked
Filter elements, O-rings and static seals, gauge glasses and level switches have measurable geometry and a stated material, so a verified alternative can be reviewed where the buyer's approval requirements allow, with dimensions and material documents checked at RFQ stage.
Obsolete controllers: both routes on paper
For Saia PCD2 and PCD4 controllers the maker's own answer is a PCD3 conversion kit or a new control system. A like-for-like module can be searched for on the market, with its origin and condition stated, but the quotation sets the maker's conversion route beside it so that the owner makes the choice.
Drives and bridge items by their own plates
Starters, frequency drives, levers, indicators and pitch feedback units carry designations of their own, and the route depends on whether the system has to be surveyed again once the work is done.
Brunvoll thruster parts — common questions
The plate starts with AR. Is it the retractable thruster or the Combi?
It can be either: the maker lists the Retractable Azimuth Thruster and the Retractable Azimuth Combi Thruster under AR designations. The Combi has a nozzle designed to fit into the hull tunnel and a top motor in a reinforced housing that forms part of the moving column, and it works as a tunnel thruster when retracted. Tell us which one is fitted and send a photograph of the unit in the thruster room; the nozzle, column and motor lines differ.
Our thruster cabinet runs on a Saia PCD2 or PCD4. Can you supply the controller?
We can look for one and will say where it comes from and in what condition. The maker, though, describes PCD2 and PCD4 as obsolete at Saia for some time and says it can no longer promise future spare parts for them. Its own answer is a conversion kit that fits a PCD3 into the existing cabinet without replacing cabinets, wiring, panels or sensors and without changes to the pitch feedback, or a new control system. We put both routes on the quotation so that a one-off replacement is chosen knowingly, not by default.
Our thrusters were converted to EAL. Does that change a seal order?
Yes. Brunvoll's conversion is a split system: the environmentally acceptable lubricant sits only in the hub with its blade seals and at the propeller shaft main seal, while the gearbox keeps mineral oil behind static seals. The conversion modifies the thruster and its operating systems and includes an upgrade of the pitch mechanism, so seals for a converted unit are read against the conversion. Tell us whether and when the conversion was made, and which oil is in which system.
The gearbox plate says Volda and the control panel says Mar-El. Are those Brunvoll?
Since 2017, yes. Brunvoll bought Scana Propulsion that year, with Scana Volda, which builds gearboxes, CP propellers and control systems, and Scana Mar-El, which builds control systems for propulsion, manoeuvring and steering gear, including the Neptune and Triton families. The maker still lists separate service contacts for thrusters, for gearboxes and propellers, and for the Triton and Neptun systems, so each line is quoted against its own plate.
Do we need to dock the ship to change shaft seals?
It depends on how the thruster is mounted. The maker designs trunk-mounted and resiliently well-mounted tunnel units and bolt-in propulsion azimuths to be lifted out without dry-docking, and offers retractable units with options for service afloat. For other units its service guidance is to plan work around scheduled dockings. That decision belongs to the owner and the yard, and it sets the window the parts have to reach.
Is Vessel Core connected to Brunvoll?
No, and there is no agreement of any kind. Vessel Core holds no distribution, representation or partnership agreement with Brunvoll, and quoting a component against one of its designations implies no approval by the maker and no claim of interchangeability.
Send the plate and the cabinet together.
List the Brunvoll parts needed, whether shaft or blade seals, blade bearing liners, hydraulic items or control cabinet parts, and attach a photograph of the thruster plate and of the open control cabinet. Say whether the unit runs mineral oil throughout or the split EAL system, and give the port. Vessel Core checks the route for each line and sends a structured quotation.
