Metal Fabrication Resources by Blackstone Advanced Technologies

Blackstone Advanced Technologies Blog
Oct 25, 2019 10:00:00 AM

Marine Grade Aluminum vs. Marine Grade Steel

Aluminum and steel are both hard metals suitable for ships and other naval vessels. While they both look and seem similar, there are a few major differences between them. Consumers who don't know the differences between steel and aluminum may end up choosing the wrong material for their ship, leading to complications here and there.

With that said, here is a rundown for steel and aluminum for ships, boats, and other naval vessels:

What Is Steel Used For?

Steel is commonly used for hulls in ships and other components. As other materials such as wood have not panned out well for use on the water, steel has been known to be a material that is more than formidable for long-term performance in the structural support of naval vessels.

What Is Aluminum Used For?

Aluminum is used in a limited amount of parts compared to steel in ship-building. Aluminum does not last as long as steel in terms of longevity, but it is more ideal for boats that are smaller and need to move faster than larger boats. Finishes have been developed for today's aluminum boats to extend their life on the water.


--aluminum canoe

What Are The Main Features Of Steel And Aluminum?

Steel is known for being strong, resilient, and long-lasting. Additionally, it is easy for ship builders to weld steel together to give the ship form, shape, and structure. Steel used for ship-building is also known to be affordable, even for large, heavy boats. Steel is typically the go-to material for ships in order to last the longest on the water possible.

Aluminum is known for being lighter and more aerodynamic, thus, you will find aluminum in smaller boats to make them travel faster in the water. In larger boats and ships, you might find some components of steel replaced with aluminum in order to get the best of each material depending on its use. For instance, steel could be used for structural support and foundation, whereas aluminum can be used in the same boat to make it lighter and less likely to capsize.

What Grades Do Steel And Aluminum Come In?

For steel suitable for marine use, there is 316-grade stainless steel. This steel extra nickel and molybdenum so it's strong and resistant to corrosion.

For aluminum suitable for marine use, you can buy 5000 or 6000 series aluminum alloys. These grades indicated they are the strongest and most immune to corrosion compared to all other aluminums.

What Finishes Do Steel And Aluminum Come In?

Steel on its own can become corrosive and rusty over time, which originally does not make it seem like a material that is suitable for aquatic use. For steel, a polished finish will prevent this from happening earlier than expected. A polished finish will allow chromium inside the steel to react with oxygen that will form a layer on the surface that helps shield water. If stains appear on the surface of steel, they can fortunately be removed after another finish.


--powder coat

Aluminum is more vulnerable to the effects of saltwater, so it requires more care to stay safe. Aluminum requires a powder-coated or anodized finish. From anodizing, aluminum reacts to a chemical to oxidize its surface, creating a textured layer that looks appealing. Powder-coated finishes involve the additional layer being chemically-bonded to the surface of aluminum. It is typically easier to re-coat an aluminum surface with powder-coat over anodizing.


Steel and aluminum have special grades for aquatic use, but they both serve unique purposes for building ships. One type of metal is not typically considered better than the other, and it should ultimately depend on the size of the ship you want to build. If you are crafting a small boat or ship, choose aluminum; Otherwise, you will want steel. If you need a large ship and want it to be the lightest weight possible, you can incorporate both materials into your plans.



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