The marine label is on the data sheet, but the order is still steel

Plenty of pages in this catalogue carry the word shipbuilding. The ST12 cold rolled sheet page lists construction, machinery manufacturing, container manufacturing, shipbuilding and bridge construction among its applications, and the DX54D+Z galvanized coil listing puts shipbuilding beside steel structure and automobile chassis. Those mentions are the supply side telling the truth: before a vessel or an offshore module is a corrosion problem, it is a stack of plate, sections and coated sheet bought in tonnage, and a buyer who treats the marine word as a grade will overpay for the wrong parts. The alloy ladder for seawater deserves its own conversation; this one is about everything the yard needs before that ladder is even opened.

The structural spine is a hot rolled plate order

Hull blocks, deck panels and topsides floors all start as plate, and the plate economics are published. The hot rolled Q235 plate page lists a 0.3 to 200 mm thickness span in coil lots of 3 to 18 tonnes, cut in the three regular mill widths with 6000 tonnes of monthly inventory and a unique number carried on each roll. The sister grades matter to the weight budget: Q345 raises the yield over Q235 for the same chemistry family, A36 serves the welded, bolted or riveted general structural duty, and the coil equivalents such as Q345 coil and A36 coil feed the panel lines. In general practice the governing thickness on a hull or deck comes from classification rules plus a corrosion allowance rather than from strength alone, which is why panel-line buyers care more about consistent thickness across the coil than about the last few megapascals on the certificate.

Frames, stiffeners and the section stock

Every plate panel is stiffened, and the sections behind it are equally standardised. The A29M H-shape page documents the family from 5 to 34 mm section thickness with flanges 50 to 400 mm wide and 8 to 64 mm thick over a web running 100 to 900 mm deep and 5 to 16 mm thick, supplied in 6 to 12 metre lengths at plus or minus one per cent, with chemical composition, mechanical testing and metallographic inspection before release. The A36 universal beam, the SS400/Q235B/Q345B I-beam and galvanized H listing and the 50x150 mild steel H-beam fill the light and medium frames, and where accommodation steel or deck fittings will sit exposed, the hot-dip galvanized H-beam option buys a zinc layer at the section stage instead of a paint cycle later. Cutting, bending, punching and welding are all listed as processing services on the section pages, which matters because a yard that receives frames pre-cut to length spends its labour welding, not measuring.

Accommodation and outfitting are a coated sheet order

Inside the hull the material changes character entirely. Cold rolled ST12 sheet and DC01 cover linings, furniture and cabinet work, and the coated range takes over wherever moisture is routine: galvanized plate in 0.19 to 2 mm thickness and widths to 2500 mm on the sheet pages, Z275 coil in 0.12 to 3 mm with coating from Z60 through Z275 and certificates to SGS, BV and ISO 9001, and prepainted material such as PPGI coil or PPGL for cabin and trunking panels where the finish is part of the specification. Corrugated profile from the galvanized corrugated plate and prepainted galvalume roof pages closes deckhouse and ventilation work, and the lighter electro-galvanized grades such as the SECCN2 coil suit interior trim where coating mass is specified by the gram. The galvanized processing chain turns any of it into cut, bent and welded parts before shipment.

Seawater systems are a second order with a society stamp

The ballast, cooling and firefighting systems belong to a different conversation, but one clause of it belongs here: certification. Duplex piping such as S31803 and S32205 is inspected to TUV, SGS, BV, ABS and LR on its own page, with squash, extended, water pressure and crystal rot tests listed, and 2205 seamless pipe carries the same regime with a one tonne minimum. Where the alloy ladder does climb, the 254 SMO page names seawater cooling, ballast systems and firefighting lines among its uses, and Alloy 625 lists special seawater applications. The point for the package buyer is procedural: the seawater order will name a classification society, so it should be placed with stock that already carries third-party inspection rather than with generic pipe. Plate follows the same rule at the top of that ladder, with Alloy 825 stocked in 4.8 to 50.8 mm thickness specifically for corrosion duty including offshore oil and gas production.

Small parts decide the maintenance schedule

Mooring, rigging and fastening hardware fail long before structure does, and the catalogue covers them too. Stainless wire rope is described on its page as indispensable in marine engineering for fixing platforms and towing ships, with the custom diameter listing spanning 0.8 to 21.4 mm on wooden reels. 17-4PH is recommended for the offshore sector, shipbuilding and the oil industry, with one honest caveat printed beside the recommendation: stagnant pockets of seawater attack it by crevice corrosion, so its homes are shafts and fasteners, not trapped water. Monel 400 holds the marine fixtures and fastener duties, and Grade 2 titanium bar quotes a seawater corrosion rate under 0.005 mm per year, a twentieth of 316L, with 345 MPa tensile for the internals that outlast everything bolted next to them.

Papers and packing for a sea voyage

Marine cargo punishes loose paperwork, so the delivery language on the pages is worth copying into the enquiry. The P22 alloy pipe page describes bundles protected for sea-worthy delivery, and its crate ends carry order number, heat number, dimensions, weight and bundle count; the duplex coil and pipe listings pack with waterproof polybag, wooden box, end caps and pallet; wire rope travels on wooden reels; and the A53 pages issue certificates to EN 10204/3.1B. A one tonne minimum applies on most of the stainless and duplex range, which keeps small repair lots practical. State the class society, the certificate level and the packing standard in the same breath as the dimensions, and the consignment that reaches the quay is the one that was ordered, which on a marine schedule is the only version that matters.