Still, the reverse deflector is the hinged bucket that redirects waterjet thrust to slow, stop or reverse a waterjet-driven vessel. Ningbo Ruican casts and machines these bodies to print for workboat, pilot boat, patrol craft and fast rescue craft waterjet propulsion units. Casting the deflector as one near-net-shape body removes the welded fabrication seams that crack under repeated reversing loads, and our in-house CNC work holds the pivot bores, link pads and sealing faces within tolerance so the unit drops straight onto the steering gear without rework.
Specifications
| Item | Specification |
|---|---|
| Casting process | Silica sol lost wax investment casting; water glass process for heavier sections |
| Material options | Duplex 2205 (ASTM A995 4A/5A), super duplex 2507, CF8M / 316L stainless, nickel aluminium bronze C95800, aluminium bronze C95500 |
| Dimensional tolerance (ISO 8062-3 CT grade) | CT6-CT7 as-cast; CT5 held on machined datums and bores |
| Machining | 3 and 4-axis VMC plus horizontal boring: pivot bores, link pads, seal faces, actuation flange |
| Surface finish (Ra) | Ra 6.3 um as-cast; Ra 1.6-3.2 um machined; Ra 0.8 um on bearing and pivot bores |
| Corrosion protection | Pickle and passivate to ASTM A967, or blast to Sa 2.5 with approved marine epoxy and antifouling scheme |
| Weight range | 6-180 kg per casting |
| Typical lead time | 5-7 weeks including tooling and first-article approval; 3-4 weeks for repeat orders |
Scope and options
Key features
- One-piece cast body eliminating fatigue-prone weld seams at the pivot and cheek plates.
- Near-net-shape profiling of the internal flow surface, so thrust reversal stays symmetric and predictable.
- Concentric pivot bores finish-machined in a single setup to protect bearing alignment.
- Duplex and super duplex grades for pitting and crevice resistance in warm seawater and brackish harbours.
- Nickel aluminium bronze option for cavitation and erosion resistance at high jet velocities.
- Moreover, Pattern tooling stored and maintained by Ningbo Ruican for repeat and spare-part call-offs.
Applications
- Waterjet propulsion units on patrol craft and coastguard vessels.
- Generally, Pilot boats and crew transfer vessels with high reversing duty cycles.
- Fast rescue craft and search-and-rescue hulls.
- Harbour and terminal workboats operating in shallow, debris-loaded water.
- Shallow-draft survey craft and aquaculture service vessels.
- Spare and renewal deflectors for in-service waterjet models.
Images
Quality & compliance
Every deflector ships with EN 10204 3.1 material certification traceable to the heat number, plus a dimensional report against the customer drawing. Non-destructive testing is available on request: dye penetrant on all cast surfaces, radiography on the pivot bosses and highly loaded sections, and ultrasonic testing on thick sections. Positive material identification and ferrite measurement are recorded for duplex grades. Ningbo Ruican supports your documentation pack with weld maps, heat treatment charts and surface preparation records, and can supply additional test coupons and inspection release notes for your surveyor. Classification-society type approval of the finished, installed part remains the customer’s responsibility and that of their chosen classification society; we supply the certified component and the evidence behind it, not the class certificate itself.
FAQ
How do you control distortion on a thin-walled deflector body?
Thin-walled deflector castings are gated and fed from simulation-verified rigging before tooling is cut, so fill stays even and hot spots are removed. Castings are solution annealed and stress relieved before machining, and rough machining is followed by a stabilisation pass, which together keep the flow surface true once the final bores are cut.
Can you match an existing OEM part number for a renewal order?
Yes. Send the drawing, the OEM part number and, where available, a sample or 3D scan from the removed unit. We reverse engineer only where the customer owns the design rights, then produce tooling and a first article for approval. Once the pattern is approved and stored, repeat and spare orders run on a shorter lead time without further tooling cost.
Which material do you recommend for high jet velocity service?
For high jet velocity and cavitation exposure we generally recommend nickel aluminium bronze C95800 for its erosion resistance and natural antifouling behaviour, or super duplex 2507 where chloride pitting resistance and high strength matter more. Also, final selection depends on jet velocity, water temperature, salinity and galvanic compatibility with the surrounding hull and steering gear.
What inspection documents come with each shipment?
Each shipment carries EN 10204 3.1 certification with heat traceability, a dimensional inspection report against drawing, material test reports, and any NDT reports requested on the purchase order. Additionally, surface preparation and coating records, heat treatment charts and PMI results are added where specified. In general, first-article inspection reports are available for new tooling programmes.
Do you machine the deflector complete, or supply it rough?
Both. Most customers take the deflector fully machined on the pivot bores, link pads, actuation flange and seal faces so it bolts straight onto the steering gear. In general, others prefer a semi-finished casting with defined machining allowance for final line boring in their own workshop. Also, we quote either route and state clearly which surfaces are machined and which are left as-cast.
How is the casting protected for a long sea shipment?
After final inspection, castings are passivated or primed as specified, then wrapped in vapour corrosion inhibitor paper, bagged with desiccant and crated in fumigated timber with blocking and bracing to stop movement. Also, machined bores and seal faces get mechanical protection caps. Photographs of the packing are sent before dispatch for your records.
CTA
Send your waterjet reverse deflector drawing, material specification and required quantity to Wendy She at sales@cnsandcasting.com, or message her directly on WhatsApp at +86-13777124360, for a quotation from Ningbo Ruican within two working days.
