Why are aluminum boats more expensive

Aluminum or polyester hulls - what are the advantages and what are the disadvantages?

Choosing the hull material for your boat is important. Before you decide on aluminum or polyester, the respective advantages and disadvantages must be weighed against each other.

1) aluminum hulls:

Advantages:
Aluminum is significantly lighter than steel, but at the same time of comparable resistance and rigidity with similar thickness.
Hulls made of aluminum are solid: hulls made of this material are used by seafarers who travel long distances and often also through the polar seas.
The non-ferrous metal does not rust. Its color can dull over time due to the thin layer of gray aluminum oxide that protects it from corrosion.

Disadvantages and recommendations:
Aluminum is a very conductive material. It is prone to electrolysis in the form of pitting (galvanic and electrolytic corrosion).
The hull must be well insulated.
For ships that remain in the water for a long time, certain essential precautions must be taken:
The underwater hull must be protected by a suitable system, whereby a special primer for aluminum hulls must be applied beforehand and only then the compatible antifouling. These colors can be purchased from the ship chandlers.
Sufficient numbers of sacrificial anodes (8 for a hull length of 10 m) must be attached: zinc for seawater, magnesium for freshwater and aluminum for use in rivers and lakes.
The navigation devices and electrical circuits must be perfectly insulated. In addition, all metal parts (motor, pumps, valves, etc.) must be connected to the shore power earth.

The Band of Boats tip: To protect against grounding on a catwalk, a galvanic isolator must be installed. Don't forget to put a ground strap between the negative battery post and the aluminum hull.
Shipyards that build aluminum hulls have made great strides, especially in argon welding technology. The so-called "STRONGALL" technology enables simplified, very solid, rigid and impact-resistant constructions.
Qualified welders are difficult to find when repairs are needed. (You must be certified)
In terms of prices, aluminum is around 20% more expensive than polyester.


2) POLYESTER HULL:

The advantages:
Composite materials are made up of resins, often with a polyester matrix and fiberglass reinforcement. These elements, coated with gelcoat as skin, are easy to care for, robust and light.

The disadvantages:
Their durability is mediocre due to the chemical degradation of the resins. This is created by osmosis. The water penetrates the gelcoat. It damages the resin, the chemical components of which release an acid. This acid creates pressure with the formation of bubbles under the gelcoat. The fiber absorbs this moisture like a sponge. The material soaks up with water, softens, becomes brittle and rots.

How is osmosis treated?
The osmosis must be treated quickly and the gelcoat of the trunk exposed.
Specialized shipyards work mainly with water jet or planing techniques.
After about 6 months, the hull has expelled the acid.

With certain special products, osmosis can be prevented when buying a new or used boat.

Band of Boats recommends that you adapt the hull to your sailing area. Aluminum is more resistant when driving in ice-rich regions or when encountering floating objects. Apart from that, the budget and the ease of maintenance and repair are decisive factors in the decision: Buy the ideal boat or have it built?