Berg Propulsion CPP & Thruster
Spare Parts Supplier
Controllable pitch propellers, MTA azimuth and MTT tunnel thrusters and MPC800 propulsion control, for engine-room and thruster-room enquiries — whether the plate reads Berg or Caterpillar
Berg Propulsion equipment seen in shipboard enquiries
Berg Propulsion designs and builds its propellers and thrusters in Sweden, with the head office at Hönö and production at Öckerö outside Gothenburg. The company dates itself to 1912 and a small Swedish shipyard, and has built controllable pitch propellers and heavy-duty thrusters since the late 1920s. Its propellers turn behind general cargo ships, product tankers, ferries, fishing vessels, tugs and offshore tonnage, and the families below are the ones a ship's documents or a plate are likely to name.
Controllable Pitch Propeller
Berg's main-shaft propeller, the blades turned in the hub by hydraulic pitch control, for diesel-mechanical and diesel-electric plants. The hub circulates its oil with integrated moisture monitoring, and that one oil both lubricates the hub internals and carries the pressure that moves the blades. Blade seal kits, hub components and pitch hydraulic items are the recurring lines.
BCP hubs · feathering
BCP, for Berg Controllable Pitch Propeller, is the hub name under which Berg launched a feathering design that works inside its standard hydraulic hub, with pitch running from full astern through full ahead to feathered, and later offered the option across its BCP hubs. On twin-screw ships one propeller can be feathered while the vessel runs on the other shaft. Say in the enquiry whether the propeller documents mention BCP or feathering.
Fixed Pitch Propeller
Berg also builds fixed pitch propellers for steady-load operation. With no pitch mechanism in the hub, the hub-oil and pitch-hydraulic items do not apply, and the recurring lines move to the shaft line: stern tube bearings, the stern seal and their gaskets.
MTA series
Berg's steerable thruster, with a controllable or fixed pitch propeller, often in an integrated nozzle. The Z-drive takes a horizontal input shaft from an engine or a motor; the L-drive takes a vertical input shaft from an electric motor. Berg names tugs, ferries and offshore vessels as its usual applications; gear sets, bearings, shaft seals and steering seals as the recurring lines.
MTT
Bow and stern transverse thrusters with fixed or controllable pitch, driven by an electric motor, a diesel engine or a hydraulic motor, and built in modular form so that key components can be exchanged as units. Propeller-shaft seals, gear and bearing parts and, on controllable pitch units, hub seals recur.
MPC800
Berg's marine control system for its propellers and thrusters, on a redundant dual-processor architecture with interfaces to joystick, autopilot, DP and VDR. Where the panel on board does not show MPC800, a photograph of it settles more than a guess at its name. Control modules, panels and levers are the lines it brings.
Switchboards, drives and NFS
On hybrid and electric packages Berg also supplies main switchboards, variable frequency drives and a Net Frequency Stabilizer for shaft generators. These are reviewed as electrical equipment rather than as propeller parts.
Where a propeller or thruster enquiry usually starts
Propeller and thruster work follows dockings and oil condition more closely than running hours. Most Berg enquiries trace back to one of these five situations, and naming which one is in front of you shortens the parts list.
Water in the hub oil
Berg hubs circulate their oil and watch its moisture content, so a seal problem usually shows up as a rising water reading or a wet oil sample before any oil reaches the surface. The routes in are the blade seals at the blade roots, the hub's own static seals and the propeller-shaft seal at the stern tube. Water here does double damage, because the same oil lubricates the hub internals and transmits the pitch pressure. Renewing blade seals means opening the hub, which is normally planned around a docking, so the seal kit, the O-ring set and the stern seal parts belong on one list.
Pitch that lags, overshoots or drifts
When pitch follows the lever late, overshoots or creeps away from its setting, the cause usually sits in the hydraulic circuit outside the hub: worn pump elements, sticking control valves, or filters loaded with particles and oil degradation products. Berg itself ties maintenance of this system to oil condition — water saturation, particles, degradation — with offline filtration as part of it, so the latest oil report belongs with the enquiry.
Lever and pitch indicator disagree
A gap between ordered and indicated pitch, alarms on pitch feedback, or a panel dropping to backup control point to the feedback transducer, its linkage or the control electronics rather than to the hub. Berg lists control system electronics among its own spare-parts lines, and the panel actually fitted, not the family name, decides which module fits.
Gear, bearing and seal wear in MTA and MTT units
In azimuth and tunnel thrusters the gear set, bearings and shaft seals run in the thruster's own oil. Metal in that oil, water entering through a propeller-shaft seal, or new noise from the gear housing are the usual first signs. On an MTA unit the steering mechanism that turns the thruster adds its own seals and bearings to the list.
Stern tube bearings and seals
A shaft-line CPP sits at the end of a shaft line with its own stern tube bearings, the stern seal and, inboard, the seals where the pitch oil enters the rotating shaft. Berg supplies shaft-line bearings and seals as part of its own parts range, and a propeller enquiry that leaves the shaft line out tends to come back as a second enquiry.
Propeller, pitch-system and thruster parts on Berg RFQ lines
A Berg request is three lists under one plate: what sits in the hub, what sits around it in the pitch system, and what sits in a thruster. They are grouped that way here because a line from one list never fits a unit on another. Berg also sells task-based service kits for defined maintenance jobs; if an earlier kit reference exists for the unit, send it.
- Blade seal kits and hub O-ring sets, per hub type
- CPP blades, blade bolts and their locking hardware
- Hub internal components as named in the part book for that hub
- Seals and bushes where the pitch oil enters the rotating shaft
- Pitch-system hydraulic pump units, pump elements and couplings
- Control, proportional and relief valves of the pitch circuit
- Pressure, return and offline filter elements
- Oil condition and moisture sensor items
- Pitch feedback transducers and linkage parts
- MPC800 and other Berg control-system modules, panels and levers
- MTA and MTT gear sets, bearings, propeller-shaft seals and steering seals
- Stern tube bearings, stern seal kits and shaft-line seal parts
What makes a Berg propeller or thruster enquiry quotable
Propeller and thruster parts are ordered against the installation, not against a catalogue table. A plate on a hub can rarely be read while the ship is afloat, so the drawing set and the documents aboard often say more than the plate does. One ship can carry a Berg propeller, Berg thrusters and a Berg control system at once, so name the unit first; the RFQ evidence guide lists what else to attach.
- Which unit the request concerns: shaft-line CPP, FPP, MTA azimuth thruster, MTT tunnel thruster or the control system
- The maker name exactly as on the plate or drawing — Berg, Caterpillar or Cat — without correcting it
- The designation exactly as printed, in the form Berg uses, for example MTA836 or MTT216
- Serial, order or project number from the plate or the propeller documents
- Year of build or delivery, which places the unit before, during or after the Caterpillar period
- Hub type where the documents name it, and whether the propeller can feather
- The control panel on the bridge, photographed rather than described, whether or not it reads MPC800
- The vessel's IMO number, for which Berg's own spare-parts form has a field
- Drawing and position number, or the page from the parts book
- The latest hub-oil or thruster-oil report where seals or gears are in question, with photographs of the plate and the removed part
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. For a controllable pitch propeller, the propeller slip calculator works out the apparent slip from the pitch, the shaft speed and the ship speed by log or GPS.
Underwater parts, pitch-system parts and consumables take different routes
Requests for Berg equipment arrive mixed, and the review follows what each line touches.
Blades and hub internals: OEM-route by default
Blades, hub internals and blade seal kits belong to a docking and to the class surveyor who sees the propeller opened. Berg engineers its blades for the installation, so these lines are checked against the vessel's own installation record on the OEM-route; where that record cannot confirm a match, the reply says which drawing the reference rests on instead of filling the gap.
Consumables: a verified alternative where approval allows
Filter elements, O-rings, hoses, gaskets and standard hydraulic valves that carry a readable sub-supplier reference are ordinary supply questions. A verified alternative can be examined on them where the buyer's approval list permits, once size and material have been confirmed at RFQ stage.
Feedback, control and pumps in between
Pitch feedback transducers, control modules and pump units carry either a Berg reference or a sub-supplier's own, and that decides the route. Each line on a mixed list is marked separately, so a hub seal kit and a filter element on the same request get different answers.
A Caterpillar plate is read as Berg
A CPP or thruster delivered between 2013 and mid-2020 may carry Caterpillar branding while the design came from the same Swedish company at Öckerö. It is read against the same Berg documentation, and the plate name is kept as it reads so that the maker's records can be matched.
Shaft line on the same list
Stern tube bearings, stern seals and the seals where the pitch oil enters the shaft belong to Berg's own parts range. They are read together with the propeller lines, because the docking that opens the hub is usually the one that reaches the stern seal as well.
Berg Propulsion CPP and thruster parts — common questions
My propeller plate says Caterpillar, not Berg. Is it the same equipment?
Very likely. Caterpillar completed its purchase of Johan Walter Berg AB in 2013 and rebranded the Berg Propulsion products Caterpillar; in mid-2020 the company, then Caterpillar Propulsion AB, passed to a new owner and its products were branded Berg Propulsion again. A CPP or thruster delivered in that period can carry Caterpillar branding on a Berg design. Send the plate as it reads, together with the build year.
Does the Kongsberg Maritime acquisition change anything for Berg spare parts?
Kongsberg Maritime completed its acquisition of Berg Propulsion AB on 1 October 2026, and the earlier agreement announcement said Berg would operate as a separate brand and standalone business unit. The plates and documents already aboard do not change with the owner, so they remain the reference for the enquiry.
Which Berg Propulsion equipment can be reviewed at RFQ stage?
Shaft-line controllable pitch propellers, including BCP hubs with or without feathering; fixed pitch propellers; MTA azimuth thrusters in Z-drive and L-drive form; MTT tunnel thrusters with fixed or controllable pitch; and the MPC800 control system or whichever Berg control panel is actually fitted. Say which unit each line belongs to, because one vessel often carries several of them.
The hub-oil monitoring shows water. What should the enquiry include?
The oil report or the monitoring trend, the hub type and designation, and the date of the next docking. Water in hub oil usually comes past the blade seals, the hub's static seals or the propeller-shaft seal, and renewing them means opening the hub, so blade seal kits, O-ring sets and stern seal parts are best quoted together for that docking.
Can CPP blades, hub parts and seals be supplied on an alternative route?
Blades and hub internals are reviewed on the maker's reference by default, because Berg engineers them for the installation and class sees them when the propeller is opened. Filter elements, O-rings, hoses and standard hydraulic items can be examined on a verified alternative where the buyer's approval list allows it, each line checked against the stated unit and drawing rather than against a family name.
Is Vessel Core connected to Berg Propulsion?
No, and there is no agreement of any kind. Vessel Core holds no distribution, representation or partnership agreement with Berg Propulsion, 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 oil report — the list follows from them.
Name the unit — CPP, MTA, MTT or control system — and send the designation and serial as they read, the build year, the latest oil analysis where seals or gears are involved, and the port or docking date. What happens after that is set out on the how we work page.
