Choosing a boat is always a trade-off between the functionality, operating conditions and budget you want. When it comes to what metal boats are made of, aluminum comes to mind most often, but the industry offers a much broader range of solutions, from light alloys for calm water to heavy-duty icebreaking hulls, each material has its own niche and unique physicochemical properties.
Understanding the differences between magnesium-aluminum and magnesium-manganese Alloys can save you from buying an unsuitable vessel that will quickly become unusable in an aggressive environment. In this article, we will take a detailed look at all types of metals used in modern shipbuilding, assess their corrosion resistance, maintainability and durability, so you can make an informed choice.
Aluminum: King of Light Shipbuilding
Aluminum is the undisputed leader in small and medium-sized craft, and it's no coincidence that this metal has a unique combination of lightness and strength, and the main advantage is its high specific strength, which allows for lower fuel consumption, but pure aluminum is almost never used in shipbuilding because of its softness.
For the manufacture of buildings used special aviation and shipbuilding It's the additives that shape the structure of the metal, making it resistant to dynamic loads and shocks to waves. Aluminum boats don't rust as we know them, because they instantly form an oxide film on their surface, which protects the deep layers from further destruction.
There are two main types of aluminum alloys used for enclosures:
- 🛡️ AMG (Al-Mg): aluminum alloys with magnesium, which have excellent weldability and high corrosion resistance in sea water.
- ⚙️ AMT (Al-Mn): Manganese alloys, which are slightly stronger but slightly less resistant to corrosion in a salty environment without additional protection.
- 🔧 Duraluminum: a high-strength alloy, which, however, requires complex anti-corrosion treatment and is rarely used for all-welded hulls of small vessels.
When buying an aluminum boat, pay attention to the thickness of the bottom - to reach large water, it should not be less than 3-4 mm, otherwise there is a risk of deformation when hitting a log.
It is important to understand that aluminum is afraid of galvanic corrosion when in contact with other metals in the electrolyte (water). zinc-treading Aluminum hull is a prerequisite for long service if you plan to use a boat in salt water or just want to be safe.
Steel boats: a choice for harsh conditions
If aluminum is a choice of speed and lightness, steel is synonymous with indestructibility. Steel boats are made from low-carbon or low-alloy boat steels. Their main trump card is their incredible strength and ability to withstand contact with ice, rocks and driftwood, which would be fatal to aluminum.
But steel has its drawbacks, which cannot be ignored: first of all, its weight; the steel case is much heavier than the aluminum case of similar size, which requires a more powerful and therefore more voracious engine; and the steel is subject to electrochemical corrosion, and without a quality paint coating, it will turn into rusty rubbish in one season of active use.
Why does steel rust faster than aluminum?
Unlike aluminum, iron oxides (rust) do not form a tight protective film; they are loose and pass oxygen to the deep layers of the metal, continuing the process of destruction until the structure is completely destroyed.
However, for certain tasks, steel remains an alternative:
- 🧊 Ice passability: Steel better tolerates compression by ice and impacts of ice crumbs at high speed.
- 🏗️ Field repairability: A hole in the steel board can be brewed in almost any conditions, even on the knee in the taiga.
- 💰 Cost of material: Steel itself is cheaper than aviation aluminum, which makes such boats more affordable in the manufacture.
When operating a steel vessel, you need to constantly monitor the condition of the vessel. corrosion-proofingAny scratch must be immediately cleaned and painted, otherwise the oxidation process will start instantly, and on steel boats it is critical to monitor the grounding system and prevent wandering currents.
Titanium and exotic alloys in shipbuilding
When you talk about the metal that premium boats or specialized machinery are made of, you can't ignore titanium, which stands out for its extraordinary performance: Titan combines the strength of steel with the lightness of aluminum, and it's more corrosion-resistant than almost all known metals, including noble metals.
Titanium boats are virtually non-corrosive even in the most aggressive marine environments, do not overgrown seashells as intensely as other metals, and have a huge resource life. But the high cost of raw materials and, more importantly, the complexity of processing make titanium the lot of the military, rescue services or very wealthy private owners.
Comparison of the main specifications of metals for shipbuilding:
| Parameter | Aluminum (AMG) | Steel (Vessel) | Titan (BT1-0) |
|---|---|---|---|
| Density (g/cm3) | 2.7 | 7.85 | 4.5 |
| Corrosion resistance | High. | Low (requires protection) | Very high. |
| Cost of material | Medium | Low. | Very high. |
| Difficulty welding | High (needs argon) | Low. | Very high (vacuum/argon) |
Titanium is justified in places where maximum reliability and minimum weight are required while maintaining strength, such as deep-sea craft or special purpose fast boats. For a normal fishing or family trip, a titanium boat would be redundant and economically inefficient.
☑️ What to look for when choosing a metal
Corrosion: the main enemy of the metal body
Regardless of which metal is chosen for the boat, the main enemy is corrosion. In the case of aluminum, it is electrochemical corrosion, which occurs due to the potential difference between different parts of the metal or when contacting other metals (for example, brass propeller), Steel is subject to classical rusting under the influence of oxygen and water.
A set of measures is used to protect metal shells. protector anodes (usually zinc or magnesium), a widely used method of cathode protection, and proper painting with special soils containing zinc (zinc-filled soils) that create a barrier layer is also important.
⚠️ Warning: Never wash an aluminum boat with acidic products or aggressive household chemicals, which can destroy the natural oxide film and cause spot corrosion, which quickly turns into a through hole.
Special attention should be paid to hidden cavities and seams, this is where the destruction of metals due to stagnation of water and lack of oxygen begins most often, regular inspection of internal bulkheads and treatment of hard-to-reach places. corrosion inhibitors Or a preservative will extend the life of your boat for decades.
Welding and repairability of various alloys
One of the key questions in choosing a material is the possibility of repair. If you plan to go far away from civilization, the ability to make a crack or break becomes a matter of survival. Steel is the most democratic in this regard: it can be boiled with conventional welding, gas or semi-automatic, using almost any electrodes.
Aluminum is a more complicated matter. It takes aluminium to weld properly. Argono-arc welding (TIG) Or welding in a protective gas environment (MIG) -- you can't just grab an aluminum side electrode -- the metal is instantly oxidized and floating, and that requires special equipment and a skilled welder.
Titanium structures are not repaired at home, and titanium requires complete isolation of the welding zone from the atmosphere (argon or helium chambers), as it actively absorbs gases when heated, becoming brittle.
Steel’s field-repairability is disproportionately higher than that of aluminum or titanium, making steel boats preferable for expeditions to hard-to-reach regions.
Comparison of durability and service life
The durability of a boat is directly dependent on operating conditions and quality of care. With proper maintenance, an aluminum boat can last 30-40 years or more, maintaining its running performance. Steel boats live slightly less because of the inevitable process of corrosion, although with perfect care they can stand for half a century.
Titanium boats can theoretically last forever, except for mechanical damage, but in practice their service life is limited to the wear and tear or fatigue of metal in places of concentration of stress (corners, welded elements).
⚠️ Warning: Do not keep a metal boat permanently filled with water, and contacting the inner surface with water, especially if it is not flowing, creates ideal conditions for bacteria to develop and corrosion to accelerate.
The build quality is also an important factor in durability. Insulating, residual stresses after welding and poor seam handling can negate the benefits of the most expensive alloy, so you should pay attention not only to the brand of metal, but also to the culture of the manufacturer when buying.
What to choose: final recommendations
Choosing metal for a boat is always about finding balance. If you want a lightweight, fast fishing boat on a lake or river that can be transported by car trailer or even on the trunk, then you can do it in a car. aluminum He's a leader without any choice, he doesn't require any care, he's not afraid of water.
If your element is the north, ice, drag through the stones and the absence of roads, where maximum strength and the possibility of rough repairs are important, then you should look at the road. steely They will forgive many of the operating errors that would be fatal to more delicate materials.
For those who are looking for a trade-off between strength and weight, but are not willing to overpay for titanium, there are modern, high-strength, thickened-bottomed aluminum-magnesium alloys that combine the best of both worlds while remaining affordable for the mass consumer.
The myth of "eternal" plastic
Many people think that plastic boats don't require maintenance. They don't. Plastic is aging from ultraviolet light, can crack from impact, and it's hard to repair in the field without special equipment and chemicals.
Can an aluminum boat be painted with ordinary paint?
No, ordinary paint will quickly get off aluminum. You need to use special soils for non-ferrous metals (for example, on a zinc or chromate basis) and special enamels that have elasticity to repeat the deformation of the metal under stress.
Why are aluminum boats sometimes called “sonic”?
Aluminum has high resonance properties. When a wave hits the side or during rain, an aluminum boat makes a characteristic loud sound that can interfere with quiet hunting. Steel boats sound dumber, and plastic boats are quieter than everyone else.
Do I need to lubricate the aluminum casing?
You can't lubricate the hull with oil or solidol, and it'll stick to dirt and sand that will work like an abrasive, and you can use antifouling coatings or Teflon sprays for boats to protect and improve your sliding.
How does salt affect the aluminum body?
Salt water is a strong electrolyte and accelerates electrochemical corrosion. Aluminum boats can be operated at sea, but only with active cathode protection (protectors) and regular washing with fresh water after each exit.
Which metal is better for a boat for an outboard motor 5-10 hp?
For a motor of this power, thin-walled aluminum is ideal. Steel will be too heavy, and the boat will not be able to achieve a good speed, using all the engine resources to overcome its own weight.