Specifications
| Parameter | Value |
|---|---|
| Material | AISI 316L / CF3M, duplex 2205 (ASTM A890 4A), super duplex 2507, nickel aluminium bronze CuAl10Ni5Fe4 |
| Process | Silica sol investment casting + CNC machining of shaft seats, bearing housings and mounting foot faces |
| Tolerance | As-cast ISO 8062-3 DCTG 5-6; shaft seat centres to +/- 0.05 mm, bearing housing bore to H7 |
| Surface finish | As-cast Ra 3.2-6.3 um, shot blasted and pickled; machined sealing faces Ra 1.6 um; passivated per ASTM A967 |
| Weight range | 10 kg – 70 kg per piece |
| Heat treatment | Solution annealing 1040-1100 C water quench; duplex grades solution annealed with controlled quench to avoid sigma phase precipitation |
| Inspection | CMM dimensional report, dye penetrant (PT) and ultrasonic testing (UT), radiography of web to foot junctions, load test on request, EN 10204 3.1 certification |
Key features
- Integral webs and bearing housings cast as one piece, spreading rope and wire loads into the transom structure without weld fatigue.
- Shaft seat centres machined to +/- 0.05 mm so the roller runs true and wire rope tracks centrally under side load.
- Duplex and super duplex options deliver the strength needed for high tension anchor handling and towing duties.
- Generous radii at every web junction limit stress concentrations under repeated shock loading from trawl gear.
- Cored grease channels feed the bearing housings for lubrication during operation, reducing wear between dockings.
- Corrosion resistant alloys plus passivation handle permanent immersion in the splash zone and stern wash.
- Mounting foot faces machined flat so the bracket seats fully on the transom, avoiding shimming and fretting in service.
Applications
- Stern roller brackets for trawlers and fishing vessels
- Anchor handling tug supply vessel stern rollers
- Towing and wire rope guide rollers on workboats
- Seismic and survey winch stern rollers on research vessels
- Offshore supply vessel deck machinery supports
- Cable and umbilical handling rollers on subsea support vessels
Quality and compliance
Stern roller brackets are manufactured under IATF 16949 process control with full heat traceability and EN 10204 3.1 certification covering chemistry and mechanical properties. Non-destructive examination, mechanical test witness and final dimensional inspection by IACS member class societies including DNV, ABS, LR, BV, CCS, NK and RINA can be arranged when the purchase order requires it.
FAQ
Q1. Can you cast the bracket and machine the bearing housings in one delivery?
Yes. Casting, heat treatment, CNC machining of shaft seats and bearing housings, NDT and passivation are all handled in-house, so you receive a ready to install bracket.
Q2. What is the largest stern roller bracket you can produce?
Investment casting covers brackets up to roughly 70 kg. For larger transom rollers we can supply a cast and machined bracket assembly in sections, or recommend an alternative process if the section size is beyond our casting envelope.
Q3. How do you handle alignment between the two shaft seats?
Both seats are machined in a single setup on a CNC machining centre, so centre distance and coaxiality are held within 0.05 mm and verified on a CMM before shipment.
Q4. Which alloy suits a high tension anchor handling duty?
Duplex 2205 is our standard recommendation, with super duplex 2507 for the highest loads and most aggressive conditions. Both offer far higher strength and pitting resistance than 316L.
Q5. Can you help improve an existing bracket that keeps cracking?
Yes. Share the failure history and the current drawing. We review wall transitions, fillet radii and alloy selection, then propose a revised design with thicker webs and better radii.
Q6. Do you offer replacement rollers as well?
We supply the bracket as the main scope and can source or manufacture the mating roller, shaft and bearing set, delivering a matched assembly that has been dry fitted before packing.
Talk to Wendy She – sales@cnsandcasting.com – WhatsApp +86-13777124360
