Nakashima Propeller
Spare Parts Supplier
Fixed pitch propellers, the Controllable Pitch Propeller in MODEL XL and MODEL XS, NT-F and NT-C tunnel thrusters and the boss caps behind them. Enquiries are read against the propeller drawing, the boss markings and the thruster plate, not the maker name alone.
Nakashima propulsion equipment met on commercial ships
Nakashima Propeller Co., Ltd. of Okayama, Japan, traces its roots to a copper alloy foundry opened in 1926. It now builds main propellers, controllable pitch propellers, tunnel thrusters and devices that improve the flow around the stern, with a works at Tamashima for large propellers and factories in Vietnam. Its fixed pitch propellers are designed and made to order for each ship, which is why the cards below separate equipment that carries a model designation from equipment identified by its drawing.
Fixed pitch propellers · keyless · high skew
Main propellers made as a single piece for the ship they were designed for, from tankers and container ships to passenger tonnage. Nakashima developed keyless propellers in 1971 and its high skewed propeller in 1981; current designs add tip rake and the minimum blade area NHV (Non-Hub Vortex) propeller. Requests cover a replacement propeller to the original drawing, repairs of bent or eroded blades, the propeller nut and the boss cap.
MODEL XL
The CPP model for large vessels. The hydraulic cylinder sits inside the outboard propeller hub and moves the blades directly, and proportional control valves allow fine pitch corrections such as Automatic Load Control. The hydraulics are doubled: normal and emergency control valves, and separate pumps for main and auxiliary pitch control oil. A request should say which circuit an item belongs to.
MODEL XS
The CPP model for medium and small vessels. The pitch cylinder sits in the inboard intermediate shaft; oil from the hydraulic unit passes a solenoid valve into the OD box, then a pilot check valve, and the piston turns the blades through the pitch rod and crosshead. The hub interior is lubricated with grease instead of oil, which is worth stating on any hub seal request.
MODEL NT-F · TFN types
Fixed pitch tunnel thrusters designated NT-F005 up to NT-F130, with the TFN-15S to TFN-75S types listed in the same range. Nakashima has built tunnel thrusters since 1976. The unit can be withdrawn from the hull for overhaul ashore, and its propeller shaft seal is the same type the maker fits as a main propulsion stern tube seal.
MODEL NT-C · TC-70N
Controllable pitch tunnel thrusters from NT-C010 to NT-C130, plus the TC-70N type. A high-performance filter in the gravity oil tank keeps the oil clean, and the remote-control unit at the bridge console has a touch-panel display. Nakashima also offers low-noise blades for ships such as research vessels and special shaft seals for ships with large draught changes; state either on the enquiry.
ECO-Cap · JET-CAP · Monster Package
Propeller boss caps that break up the hub vortex. ECO-Cap carries thin FRP blades on a copper alloy cap body; JET-CAP carries GFRP fins bolted to a bronze boss cap screwed onto the shaft nut, and a damaged fin can be replaced on its own. The Monster Package combines further flow-improving devices, among them the Ultimate Rudder Bulb and the Neighbor Duct, whose geometry Nakashima works on with Becker Marine Systems, a group company since 2021.
Shaft Horsepower Meter · NASCA
The Shaft Horsepower Meter, developed by group company Shoyo Engineering, uses a detection ring on the intermediate shaft, an electromagnetic induction unit and a processing and display unit; a shaft thrust load meter can be added. NASCA (Nakashima Ship Cruise Assist System) builds speed, shaft power and fuel consumption monitoring on top of it. Name the unit, not just the system.
STEER-JET · CFRP Propeller · Tandem CRP
Designs the maker presents mainly for domestic shipping in Japan: the STEER-JET bottom-intake jet thruster (SJ-010), the CFRP Propeller, which Nakashima describes as the world's first CFRP propeller for general commercial vessels, and the Tandem CRP system, in which an azimuth thruster runs behind a controllable pitch propeller as a contra-rotating pair. If one of these is fitted, the model and serial from the unit itself are the starting point.
What brings a Nakashima propeller or thruster into an enquiry
Nakashima's own after-sales list reads like a damage register: bent edges, cavitation, ageing surfaces and worn thruster seals. Each one points to a different set of parts.
Bent edges and impact damage
Contact with ice, floating debris or a quay leaves curled leading edges and local cracks. The maker's repair list covers bend correction, build-up welding of damaged areas, and splicing and welding repairs. A supply request usually follows for what is opened up with the propeller: the nut, its locking parts and the boss cap.
Cavitation erosion
Pitting near the blade tip or root is the classic sign. Nakashima's tip rake design is aimed at suppressing cavitation at the blade tip, and its repair shops build cavitation areas back up by welding. When erosion returns after every repair, the propeller design rather than the repair becomes the question; the maker also replaces propellers with designs optimised for the ship's actual operating profile. Where the ship seems to make less speed for the same shaft speed and pitch, the propeller slip calculator works out the apparent slip from the log or GPS speed.
Roughness and ageing
A rough or fouled blade surface costs fuel long before it causes damage. Polishing, cleaning and edge cutting are the maker's own remedies for efficiency lost with age, and a shaft horsepower meter is how the loss gets measured rather than guessed.
Seals, O-rings and bearings
Thruster sealing systems and O-rings are rubber parts with a limited service life, and the bearings in rotating parts wear out too. Nakashima warns that a thruster put out of action by poor maintenance can leave the owner with tug and labour costs. Seal kits, O-ring sets and bearings are best requested together, against the thruster model and serial.
Pitch that hunts or lags
A pitch that creeps, hunts or answers late points into the hydraulic chain: solenoid and pilot check valves, proportional control valves on MODEL XL, the OD box on MODEL XS, filters and pumps. The model tells you whether the cylinder is in the hub or in the intermediate shaft, and therefore which end of the shaft line the parts come from.
Propeller, CPP and thruster items handled on request
Requests range from a single cap fin to a complete propeller. The list is grouped by unit, because a fixed pitch propeller, a CPP and a tunnel thruster share a maker but very few parts.
- Replacement fixed pitch propellers to the original drawing
- Propeller nuts, locking parts and boss caps
- ECO-Cap and JET-CAP fins, cap bodies and bolts
- CPP hub seals and blade foot O-rings
- Pitch rod and crosshead parts on MODEL XS
- OD box seals and bearing items on MODEL XS
- Hydraulic unit pumps, solenoid valves and pilot check valves
- Proportional and emergency control valve items on MODEL XL
- Tunnel thruster shaft seals, O-rings and bearings
- Gravity oil tank filter elements for NT-C thrusters
- Thruster remote-control unit and display items
- Shaft horsepower meter detection ring and sensor items
Identifying a Nakashima propeller or thruster
A fixed pitch propeller has no model plate to read: it was made for one ship, so the drawing and the markings on the boss do the work a nameplate does elsewhere. CPPs, thrusters and monitoring units do carry a model. Nakashima itself asks for the damage situation and recent operation records with any service enquiry, and the same evidence settles a parts review. The RFQ evidence guide covers the photographs.
- Which unit: main fixed pitch propeller, Controllable Pitch Propeller, tunnel thruster, boss cap or shaft monitoring
- Propeller drawing number, and the shipyard and hull number it was built for
- Square-on photographs of every marking cast or stamped on the boss, including any class stamp
- Any maker's mark visible on the casting; Nakashima's trademarks have been a three-circle Mitsuwa mark, an Eagle mark and, since 1985, an N mark
- How the propeller sits on the shaft: keyless or keyed
- CPP model, MODEL XL or MODEL XS, and the hydraulic unit plate
- Thruster model as stamped (NT-F, NT-C, TFN or TC types), serial number, fixed or controllable pitch
- Boss cap type: standard cap, ECO-Cap or JET-CAP, and which fin is damaged
- Class certificate for the propeller or thruster where the item is under survey
- A description of the damage and recent operation records, with photographs of the blade or seal concerned
Supply route review for Nakashima propulsion items
A propeller is the part on a ship least open to substitution: it was drawn for one hull and one engine. The review starts from that drawing and works outwards.
Drawing before designation
For a fixed pitch propeller the drawing number is the part number. Without it a replacement propeller or a repaired blade has nothing to be checked against, so the drawing, the boss markings and the class certificate are settled before any route is discussed.
The maker's route where the work is the maker's
Bend correction, edge cutting, dynamic balancing and CPP or thruster service are workshop and technician jobs: Nakashima keeps dynamic balancing machines at each repair facility and sends technicians out for CPP and thruster work. Where a request is really a repair, we say so rather than quoting parts around it.
Equivalent source where the item allows it
Thruster seal kits, O-rings, bearings, filter elements and hydraulic valves are standard components inside a maker's assembly. They can be reviewed on an equivalent-source path, subject to the buyer's approval list and class requirements, against the thruster model and serial rather than the maker name alone.
Two models, two ends of the shaft
On MODEL XL the pitch cylinder is in the outboard hub; on MODEL XS it is in the inboard intermediate shaft, next to the OD box. A CPP list is read against the model first, because the same word, cylinder, points to parts in different places.
Older builds
Nakashima's history records technical cooperation with Stone Manganese Marine of England on controllable pitch propellers and side thrusters in 1972, and its tunnel thruster table notes that some models may be of a conventional type. On an older unit the build year and serial carry more weight than the current catalogue.
Nakashima Propeller parts — questions from superintendents
Which Nakashima equipment can be reviewed at RFQ stage?
Fixed pitch propellers, the Controllable Pitch Propeller in MODEL XL and MODEL XS, tunnel thrusters of the NT-F and NT-C ranges together with the TFN and TC types, ECO-Cap and JET-CAP boss caps, and the Shaft Horsepower Meter. Send the drawing number or the model as stamped, with photographs of the boss markings or the unit plate.
Our propeller has no nameplate. How is it identified?
Nakashima builds fixed pitch propellers to order for each ship, so there is no catalogue model to quote. The propeller drawing number, the shipyard and hull number, the markings on the boss and the class certificate identify it. If the drawing is missing, square-on photographs of every boss marking are the next best evidence.
What is the difference between MODEL XL and MODEL XS for a parts request?
Where the pitch is actuated. MODEL XL, for large vessels, has the hydraulic cylinder inside the outboard hub and a doubled hydraulic circuit with normal and emergency control valves. MODEL XS, for medium and small vessels, has the cylinder in the inboard intermediate shaft, fed through the OD box, and a grease-lubricated hub. Name the model before listing seals or valves.
Which tunnel thruster items belong in a maintenance request?
Nakashima names the sealing systems, O-rings and rotating-part bearings as the items with a limited service life. A maintenance request usually groups them with the propeller shaft seal and, on NT-C units, the gravity oil tank filter element. Quote the model as stamped, for example NT-C040 or NT-F020, and the serial number.
Can a damaged ECO-Cap or JET-CAP fin be replaced on its own?
On a JET-CAP, yes: the GFRP fins are bolted to the bronze boss cap, and the maker states that a damaged fin can be replaced individually. The ECO-Cap carries thin FRP blades on a copper alloy cap body. In both cases state the cap type, the propeller drawing number and which fin or blade is damaged.
Is Vessel Core connected to Nakashima Propeller?
No, and there is no agreement of any kind. Vessel Core holds no distribution, representation or partnership agreement with Nakashima Propeller, and quoting a component against one of its designations implies no approval by the maker and no claim of interchangeability.
Send the drawing number or the thruster plate
Attach the propeller drawing number or the model as stamped, photographs of the boss markings and a short note on the damage. The review starts from that evidence. Send an RFQ.
