Marine & shipbuilding

Aluminium for Marine & Shipbuilding

Seawater-resistant aluminium for hulls, decks, superstructures and offshore structures. Metline Industries supplies marine plate, extrusions, tube and bar from Mumbai, close to India's major ports and shipyards.

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Key alloys: 5083, 5086, 5052, 5059, 6061
Marine tempers: H111, H116, H321
Forms: Plate, sheet, extrusions, bar, tube
Benefit: Lighter, faster, lower maintenance

Overview

Why boats are built in aluminium

An aluminium hull is significantly lighter than an equivalent steel hull, so a vessel carries more payload, needs less power or goes faster. Marine alloys resist seawater without paint, and aluminium does not rot or degrade like wood or some composites.

The key is choosing true marine grades. The 5xxx alloys, with magnesium as the main addition, combine strength with excellent seawater resistance and weld well. The marine tempers H116 and H321 are specially tested for resistance to exfoliation and intergranular corrosion.

Applications

Where aluminium is used

Hulls and bottom plating

5083 and 5086 plate in H116 or H321 for welded hulls.

Decks and superstructures

Lighter plate and 6xxx extrusions to keep the centre of gravity low.

Fast ferries and patrol boats

High-strength 5059 and 5383 for weight-critical vessels.

Offshore structures

Helidecks, walkways and gangways that stand up to salt spray.

Fittings and hardware

5052 and 6061 bar, tube and flat bar for rails, cleats and davits.

LNG and cryogenic tanks

5083 keeps its toughness at very low temperatures.

Alloy selection

Recommended alloys and forms

Alloy	Form	Why it is used
5083-H116 / H321	Plate, sheet	The benchmark marine alloy for hulls and structure
5086-H116	Plate, sheet, pipe	Slightly lower strength than 5083, very good corrosion resistance
5059 / 5383	Plate, extrusions	Higher-strength versions of 5083 for weight-critical craft
5052-H32	Sheet, bar	Smaller boats, tanks and fittings
6061-T6 / 6082-T6	Extrusions, tube, bar	Stiffeners, frames, rails and fittings above the waterline

Why Metline

Supplying marine & shipbuilding

Complete material packages

Plate, sheet, extrusions, tube and bar for the same project from one supplier.

Grade and temper guidance

Engineering-led advice on the alloy and temper that suit the service conditions.

Documentation

Mill test certificates and inspection paperwork to support your quality system.

Materials

Marine & Shipbuilding materials

FAQ

Marine & Shipbuilding questions

What is the best aluminium for boat building?

5083 in H116 or H321 temper is the most widely used hull alloy. 5086 and 5052 are good alternatives for smaller craft.

Is 6061 marine grade?

6061 is widely used on boats for extrusions, rails and fittings, but 5xxx alloys are preferred for hull plating that is permanently immersed.

What do H116 and H321 mean?

They are marine tempers for 5xxx alloys that are tested for resistance to exfoliation and intergranular corrosion.

Building a vessel?

Send us the alloy, temper, plate sizes and quantities. Our Mumbai team will reply with availability and a competitive quote.

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