The trouble with round numbers is that they always feel a little contrived – especially when we talk about limits. Sailing's so‑called 50‑knot"sound barrier" is a perfect case in point.

Could it really be that such a memorable, neat half‑hundred figure just happens to coincide with a genuine physical barrier in speed sailing?

Given the enormous technological advances of the past three decades, the persistence of this human‑defined milestone seems particularly baffling.

Yet the barrier persists. To break through this"wall" without losing control, teams have poured thousands of hours into design, trying to engineer their way to the other side.

While it is safe to say that it no longer looms as the insurmountable obstacle it once was, it is equally true that bad things still happen when you hit 50 knots – especially cavitation.

Paul Larsen's Vestas SailRocket 2 remains the only boat to have smashed through that barrier decisively – cruising steadily into the 60s, with peak bursts nearing 70 knots. But to get there, they made a bold, last‑minute modification based on gut feeling rather than science.

So perhaps it is no surprise that a considerable number of boats now congregate around this speed threshold. Under the right conditions, America's Cup boats and SailGP's F50s will momentarily spike past that red line during a slingshot gybe at the top mark. Ask any helmsman what it feels like, and you get the same answer every time: sheer terror – or words to that effect.

They describe a moment when the boat takes over, and they are merely along for the ride until the cavitation stops.

At the other end of the spectrum, the 32‑metre Ultim trimarans, while flying on their foils, cruise at around 45 knots, occasionally nudging that magic number. The latest IMOCA designs are a little behind, but if these 60‑foot monohulls were allowed to fit T‑foils on their rudders, it would not be long before they entered the same speed territory.

What is particularly striking is the sheer variety of approaches being taken to push the speed ceiling – and the ambition shown by some teams in tackling this challenge.

My current favourite extreme project is the latest Ultim – Gitana 18.

Technical details such as the A‑frame rudder, America's Cup‑style canting T‑foil arms, and swinging screecher mounts (to name just a few) are hugely impressive – advances that could give them a competitive edge. This team has been working together for decades, raising the bar year after year, and building a track record of success on that foundation.

But the machine that truly took my breath away the other day – for the sheer audacity of its ambition – is the 100‑foot offshore flying monohull slated for launch later this year: the Ferrari Hypersail.

Just imagine the forces required to lift such a leviathan onto its foils while cruising at over 40 knots – it is almost inconceivable.

You might argue that the Ultim class already does that, but the difference is that if things go wrong and the boat drops off its foils, those boats can at least rely on their three hulls to (hopefully) catch them. That makes me wonder: why would the Hypersail team choose a monohull if they want to break offshore records?

The answer surprised me. Among the many reasons, the top one is rigidity. Unlike trimarans, which still flex and twist when hammering through waves – despite their carbon construction and cutting‑edge technology – a monohull is structurally far stiffer. That translates to far more precise control over the foils and their angles of attack.