The mooring bollard cross-bar head body is the cap that closes the top of a mooring bollard and carries the cross-bar or horn that stops a mooring line riding up and off the post. It sits on the open mooring deck in constant salt spray, under shock load every time a hawser surges. Traditional cast naval brass and manganese bronze heads dezincify, leaving a porous copper sponge that loses section with no visible warning, while fabricated stainless heads suffer weld decay in the heat-affected zone at the cross-bar-to-post junction. A one-piece duplex 2205 investment casting removes the weld entirely and gives a yield strength roughly double 316L, so the horn section carries surge load without the distortion and misalignment that make a socketed head bind on its post.
Specifications
| Parameter | Specification |
|---|---|
| Casting process | Silica sol lost wax investment casting; water glass route for large or non-cosmetic mooring heads |
| Material options | Duplex 2205 (UNS S32205 / EN 1.4462); AISI 316L and AISI 316 available |
| Dimensional tolerance (ISO 8062-3 CT grade) | CT7 as cast on the outer head profile; CT6 on the post socket; CT5 machined on the post bore and rope bearing radius |
| Machining | CNC turning of the post socket bore, 4-axis CNC milling of the underside seat and horn radii, drilling of the drain port |
| Surface finish (Ra) | Ra 3.2 um as cast; Ra 1.6 um machined on bore and seat; Ra 0.8 um polished on the rope bearing radius |
| Weight range | 3.5 kg to 18 kg per head depending on bollard size and horn span |
| Typical lead time | Tooling 5-6 weeks; first article 3-4 weeks after tooling; production 6-8 weeks |
Key features
- Duplex 2205 at PREN 35 minimum (22.0-23.0 Cr, 3.0-3.5 Mo, 0.14-0.20 N) gives roughly twice the pitting resistance of 316L in warm seawater.
- Solution annealed at 1020-1100 C and water quenched, with the furnace chart released, to hold the ferrite-austenite balance in the 35-55 percent range.
- Monolithic cast head removes the eight fillet welds at the cross-bar-to-post junction, the classic site for weld decay and under-deposit attack.
- Rope bearing radius polished to Ra 0.8 um, cutting fibre abrasion on 40-64 mm mooring tails and hawsers under surge load.
- Post socket bore machined to CT5, holding bore size within +/-0.1 mm so the head drops onto the bollard post without heat or force.
- Yield strength near 450 MPa, about double 316L, lets the horn section be thinned without losing line-load capacity.
- Cast drain slot at the socket bottom stops water standing in the joint, the failure source that freezes and splits socketed heads in winter service.
Applications
- Foredeck and afterdeck mooring bollards on harbour tugs and escort tugs.
- Deck edge bollards and mooring heads on workboats and pilot boats.
- Mooring stations on passenger ferries and ro-pax vessel ramps.
- Marina and quayside bollards, plus superyacht mooring deck hardware.
- Mooring decks on offshore service and platform supply vessels.
- Barge, hopper and dredger mooring points in estuarine and brackish water.
Quality & compliance
Moreover, Ningbo Ruican casts and machines to IATF 16949 process control and works to ISO 9001 documentation practice. Every shipment carries EN 10204 3.1 material certification tied to the heat lot, with solution-anneal and water quench furnace charts, chemical analysis and mechanical test results. Generally, PPAP and FAIR packages are available to the customer’s submission level. In general, the first article ships with a full dimensional report covering every ballooned feature on the drawing. Duplex 2205 lots receive ferrite count by point count or magnetic measurement, targeting 35-55 percent, and intermetallic phase verification to the buyer’s specified method. Positive material identification, non-destructive testing and inspection acceptance level are all supplied to the standard the buyer names on the drawing and order.
FAQ
Can you work from an existing bollard head sample?
Yes. Send the sample or a worn head and we 3D scan the outer profile, socket and horn geometry, rebuild a model and return a drawing for approval before tooling. We confirm bollard post diameter, socket depth, horn span and the line load the head must carry. Where the original dezincified or cracked, we usually recommend a small section increase at the horn root, quoted separately so you can decide whether to keep the legacy profile. Tooling takes five to six weeks.
Do you supply duplex 2205 with a ferrite count and no sigma phase?
Yes. Generally, duplex heads are solution annealed at 1020-1100 C and water quenched, with the furnace chart released with the lot. Where the drawing requires it, ferrite is measured by point count or magnetic gauge and reported against the 35-55 percent target, and freedom from sigma and chi phase is verified to the buyer’s specified test method. PMI is available on request, and results are reported with the first article and at the production sampling rate in the control plan.
What is the minimum order quantity?
We accept prototype and pilot quantities from a single tooling set, which suits refit and replacement work, then scale to series production with multi-cavity tooling once annual volume justifies it. For bollard heads the practical first release is around 20 to 50 pieces. In general, tooling is maintained and stored for repeat orders across the vessel programme. Also, we can hold agreed safety stock against a released delivery schedule.
Do you machine the parts fully in-house?
Yes. Casting, solution annealing and quenching, CNC turning, CNC milling, drilling, polishing and passivation all run inside our Ningbo facility under one IATF 16949 control plan. Holding every operation in-house means the socket bore and the rope bearing radius are machined from the casting datums we created, so bore size, concentricity and seat flatness are verified against your drawing by one inspection team before release.
Can you match an existing class-approved part?
We reverse engineer an existing part, match the drawing geometry, material and heat treatment, and supply EN 10204 3.1 certification, dimensional reports and NDT evidence to the standard you specify. Also, Ningbo Ruican holds no classification-society type approval and claims none; any class survey. It also holds plan approval or type approval remains the responsibility of the shipyard. It also holds the equipment maker and the society. In addition, we supply the evidence package your surveyor reviews.
CTA
Send your mooring bollard cross-bar head drawing, sample or 3D model for a DFM review, material recommendation and tooling plus piece price. Contact Wendy She — sales@cnsandcasting.com — WhatsApp +86-13777124360, or visit https://cnsandcasting.com to start your marine deck hardware program with Ningbo Ruican.
