Schottel Thruster & Propulsion
Spare Parts Supplier
RudderPropeller SRP, EcoPeller SRE, TwinPropeller STP, TransverseThruster STT, PumpJet SPJ, ControllablePropeller SCP and RimThruster SRT: seal, gearing and control lines, read from the plate and the unit's serial
A propeller that steers, and the families built around it
SCHOTTEL GmbH was founded in 1921 by Josef Becker at Spay on the Rhine, and the SCHOTTEL Group describes itself as an independent family-owned business with further production at Dörth and Wismar. Schottel dates its rudder propeller to 1950: Becker's unit combined propulsion and steering, so the ship is steered by turning the propeller itself rather than a rudder blade, and in 2004 he was honoured posthumously with the Elmer A. Sperry Award for it. Every unit below is ordered against its family letters and the type designation on the plate, and the family decides which gearbox, seal and steering arrangement a part belongs to.
SRP RudderPropeller
A fully steerable unit that, in Schottel's words, makes a rudder superfluous: turning the propeller through half a circle takes the ship from full ahead to full astern. The standard types run from SRP 100 to SRP 800. Separate variants are the retractable SRP-R, the heavy-duty SRP-U, which can be mounted underwater on drilling ships and similar offshore tonnage, and the SRP-D for highly demanding DP operations.
SRP-R · SRP-RT
The retractable version of the RudderPropeller, with the advantages of the standard SRP series, and usable as a take-home system. Schottel states that the RT variant works as a transverse thruster in the retracted position, so on some vessels the unit the crew call the bow thruster is in fact a retractable RudderPropeller. The plate, not the job the unit does, decides which drawing applies.
SRE EcoPeller
Schottel calls the EcoPeller the first azimuth unit consistently developed for an electric drive source. It is offered with the embedded LE-Drive and with a fixed or a controllable pitch propeller, the CP version with a full-feathering mode. HTG gearing and LeaCon sealing are named options.
STP TwinPropeller
Two co-rotating propellers on one underwater unit share the load, an arrangement Schottel aims at vessels with limited installation space, draught or propeller clearance. LeaCon sealing and DuroVario integrated clutches are the options, so the seal and clutch lines depend on what was ordered with the unit.
STT TransverseThruster
Auxiliary drives built on the same design principles as the RudderPropeller. Fixed pitch is offered across the range and controllable pitch on part of it. A unit may sit in a well for easy maintenance access or in an elastic well installation for lower noise, and may run on biodegradable lubricants or carry LeaCon; HTG is a further option.
SPJ PumpJet
An azimuth jet drive for shallow-water operation, installed completely flush with the hull behind an inlet grid, with no protruding drive components. It serves as main or auxiliary propulsion or as a take-home system. Schottel traces its development to 1972 and a bargeman's suggestion; LeaCon and HTG are offered as options.
SCP ControllablePropeller
Shaft-line propellers whose blade pitch is adjusted for manoeuvring and for changing operating conditions, with full-feathering as an option and a hub variant for five blades. On request the scope extends to the hydraulic system, remote control, stern tube with seals, gearboxes, shaft generators, shaft brakes and nozzles. Schottel builds its controllable pitch propulsion at Wismar, where it took over WPM Wismarer Propeller- und Maschinenbau in 1999.
SRT RimThruster
The exception in the range: an electric propulsion system with no gearbox or shaft. The motor stator sits in the outer part of the tunnel and the propeller blades are attached to the inside of the rotor, which runs in water-lubricated, oil-free plain bearings. An SRT enquiry therefore carries no gear-oil items at all.
Seals, gear oil, steering and the underwater parts
A thruster works with seawater on one side of its seals and gear oil on the other. Most Schottel enquiries start at that boundary, in the gearing behind it or at the control that turns the unit.
Seawater side, gearbox side
The propeller shaft seal keeps seawater out of the gear oil and oil out of the sea. Water in an oil sample points at the seawater side; oil traces outboard point at the gearbox side. On a unit with LeaCon, separate seals on each side drain into the LeaCon chamber, a vacuum system draws the leakage into a compact tank in the engine room, and the system registers the quantity collected. That record is evidence of seal condition and belongs in the request.
Bevel gears and their bearings
Power reaches the propeller through bevel gears and their bearings, so water or metal in the oil is seldom a seal question alone. Schottel's own ProCMS condition monitoring analyses acceleration, velocity, bearing and oil temperature and water-in-oil saturation together. Some units carry Schottel's own High Torque Gear (HTG), which the maker credits with a longer gearbox service life; say whether it is fitted.
The drive that turns the unit
The azimuth steering drive turns the underwater unit, and the propulsion control sits behind it. Schottel's PropControl passes the crew's orders to the propulsion unit and also controls auxiliary units, clutches, gearboxes and motors, while the MasterStick joystick commands several units at once. Schottel says it develops and builds every element of that system, from sensors and actuators to the control desk, so control-side lines are quoted against the panel and its own label, not the thruster's type.
Below the waterline
Nozzles (SDV45 VarioDuct or SDC40 CruiseDuct where fitted), ProAnode corrosion protection, which moves the anodes from the outer surface to the outer cross-section of the nozzle, propeller blades and the PumpJet inlet grid are read from the drawing and from photographs taken in dock.
What gets ordered against a Schottel unit
Listed from the seal outward. A line naming a seal, a bearing or a gear set needs the unit's type and serial behind it, because one family spans many sizes.
- Propeller shaft seal sets, seawater side and gearbox side
- LeaCon chamber seals and leakage-tank items, where LeaCon is fitted
- Upper gearbox bearings and seals, on units built with an upper gearbox
- Underwater gearbox bearings and bevel gear sets, per serial
- Vertical drive shaft bearings and seals
- Azimuth steering drive components and steering feedback items
- Clutch parts, DuroVario integrated clutches included, where fitted
- Pitch hub seals, pitch mechanism and hydraulic items on CP units
- Gear-oil filter elements and oil temperature sensors
- Anodes and ProAnode nozzle items on the underwater unit
- PumpJet inlet grid parts
- PropControl and MasterStick panel items, control levers and indicators
- Overhaul gasket and O-ring sets, per type and serial
Which family, which type, which arrangement
Thruster parts are ordered against the family, the type and the unit's serial rather than a catalogue number, and the thruster room is rarely a place where a clear photograph is easy. The RFQ evidence guide lists what else to attach.
- Family and type exactly as stamped (SRP, SRE, STP, STT, SPJ, SCP or SRT, then the type designation), with any suffix such as R, RT, U or D
- The serial number of the unit from the type plate
- An older four-digit designation, if that is what the plate carries, sent as stamped and not converted
- Drive arrangement as the documents name it: Z, ZY (SYDRIVE), L or LE; whether the module is a compact CL or CZ; whether an electric motor sits directly on top of the unit
- Fixed or controllable pitch, and the nozzle type where one is fitted
- Whether LeaCon is fitted; a separate leakage tank for the thruster in the engine room is the visible sign
- What drives the unit, an engine through a clutch or an electric motor, and the clutch type where one is fitted
- The control system and panel label (PropControl, MasterStick) for any control-side line
- The latest gear-oil analysis, water content especially, with the oil grade in use
- Running hours since the last overhaul, the class society and the date of the next docking, with photographs of the type plate, the upper part of the unit 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.
A bevel gear set and a filter element are not answered alike
Requests naming Schottel components arrive mixed, and the review follows what each line touches.
Gearing, hubs and LeaCon: OEM-route first
Bevel gear sets, gearbox bearings opened at a class overhaul, controllable pitch hub internals, LeaCon components and anything a surveyor sees at docking go to an OEM-route review by default, checked against the unit's type and serial. Where the service history is too thin to confirm a match, the reply names the drawing the part was checked against instead of guessing.
Age is no reason to leave the maker's route
Schottel's after-sales overview lists the production of spare parts for very old propulsion units, and its service recommissions propulsion units on reactivated vessels. An old plate is therefore read against the maker's records first, under the name it actually carries.
Filters, O-rings, anodes: an alternative can be reviewed
Gear-oil filter elements, O-rings, standard rolling bearings that carry their own maker's reference, anodes and hoses are routine supply lines with measurable geometry and a stated material. A verified alternative route can be reviewed on them where a buyer's approval requirements allow, with dimensions and material documents checked at RFQ stage.
Steering and control in between
Steering drive components, sensors and control panel items sit in the middle: the route depends on whether the part carries a Schottel reference or a sub-supplier's own, and on whether the unit is presented to class afterwards. Each line of a mixed request is marked separately.
One docking, one list
Schottel's preventive maintenance guidance says vessels subject to class acceptance must be serviced at regular intervals, that components under particularly high mechanical loads are replaced, and that oil analyses and condition monitoring can find damaged parts before docking. A request that arrives with the docking date is read as one overhaul list; one that arrives after the unit is opened tends to become two.
Schottel thruster parts — common questions
Which Schottel units can be reviewed at RFQ stage?
The RudderPropeller (SRP) in its standard, retractable (SRP-R, SRP-RT), underwater mountable (SRP-U) and DP-optimised (SRP-D) versions, the EcoPeller (SRE), TwinPropeller (STP), TransverseThruster (STT), PumpJet (SPJ), ControllablePropeller (SCP) and RimThruster (SRT), plus PropControl and MasterStick control items. Send the family letters and type as stamped, the serial number, the drive arrangement and whether the propeller is fixed or controllable pitch.
Our plate reads SRP 1515, a name current Schottel material no longer uses. Can it still be quoted?
Schottel's own pages say the SRP 460 was formerly the SRP 1515 and date the first SRP 460 to 1999, and another Schottel story gives the renamed type as SRP 460 / SRP 490. Send the designation exactly as stamped together with the serial number. The request is read against the old and the new names rather than one being quietly corrected into the other, and other older designations are handled the same way, from the serial.
How do we tell whether our thruster has LeaCon, and does it change the seal order?
LeaCon uses separate seals on the seawater side and the gearbox side, with an intermediate chamber between them. A vacuum system draws the leakage into a compact tank in the engine room, and the system registers the amount collected and checks seal condition continuously. If the thruster has such a tank, LeaCon is fitted and the seal set is ordered for that arrangement. Say so in the request and send the logged readings.
The gear-oil sample shows water. What should the request contain?
The oil analysis itself, the type and serial, whether LeaCon is fitted, running hours since the last overhaul and the next docking date. Water in the oil points first at the seawater-side sealing, and Schottel's ProCMS monitoring tracks water-in-oil saturation alongside bearing and oil temperature. With those details the seal set, the gearbox bearings the overhaul opens and the filter elements can be read as one list rather than in two rounds.
Do a TransverseThruster and a RudderPropeller on the same ship share parts?
Schottel builds the STT on the same design principles as the SRP, but it is a different unit in a tunnel, and parts are quoted separately per type and serial. Note the SRP-RT: the maker states that it works as a transverse thruster when retracted, so on some vessels the bow thruster is in fact a retractable RudderPropeller. The plate decides.
Is Vessel Core connected to Schottel?
No, and there is no agreement of any kind. Vessel Core holds no distribution, representation or partnership agreement with Schottel, and quoting a component against one of its designations implies no approval by the maker and no claim of interchangeability.
Send the plate, the oil report and the docking date.
Name the family and type as stamped (SRP, SRE, STP, STT, SPJ, SCP or SRT), the serial number and the drive arrangement, and attach photographs of the type plate and of the unit in the thruster room. The how we work page explains the review that follows.
