The radical new material, called a metal matrix composite, was developed with the US Army.

A boat made of such lightweight composites will not sink despite damage to its structure.

The new material also promises to improve automotive fuel economy because it combines light weight with heat resistance.

Although syntactic foams have been around for many years, this is the first development of a lightweight metal matrix syntactic foam.

'This new development of very light metal matrix composites can swing the pendulum back in favor of metallic materials,' said Nikhil Gupta, an NYU School of Engineering professor in the Department of Mechanical and Aerospace Engineering and the study's co-author.

It was created by Deep Springs Technology and the New York University Polytechnic School of Engineering.

'The ability of metals to withstand higher temperatures can be a huge advantage for these composites in engine and exhaust components, quite apart from structural parts.'

The magnesium alloy matrix composite is reinforced with silicon carbide hollow particles and has a density of only 0.92 grams per cubic centimeter compared to 1.0 g/cc of water.

Not only does it have a density lower than that of water, it is strong enough to withstand the rigorous conditions faced in the marine environment.

-Daily mail