Twenty-five metres decides whether your Mykonos night ends on the Chora quay or at the New Port north of town. Twenty metres — and three metres of draft — decides whether Santorini's only sheltered basin has room for you at all. Twenty-four metres decides which anchoring rules you cruise under in French waters. In the Mediterranean the numbers on a spec sheet are not shopping criteria. They are access, and somebody checks them at the entrance.
The Aegean sorts boats by length before you arrive
Cycladic harbours are municipal, and their limits are published rather than negotiated. The Municipal Port Fund of Mykonos runs both of the island's ports and splits yacht traffic between them on one number: its booking procedure for the Old Port in Chora covers boats over 25 m, while the New Port reservation system at Tourlos works only for boats under 25 m. Same island, same night, two very different walks to dinner.
Santorini draws a harder line, because it barely has a harbour at all. The fishing shelter at Vlychada — the island's sheltered basin — takes boats up to 20 m long and up to 3 m of draft. That is 66 ft on 9 ft 10 in, and it is the whole envelope.
Now read a boat against those numbers. The Ferretti 580 is 59 ft 10 in (18.24 m) overall on a 16 ft 5 in (5.00 m) beam, drawing 4 ft 11 in (1.50 m), with three guest cabins plus crew and 859 US gal (3,250 L) aboard. On the standard Volvo Penta D13 900s it cruises 24 knots and tops 28; with the 1000s, 26 and 32. Nothing about that boat is small. It simply sits under every line the Cyclades draw, which in this water is the more useful kind of big. The Mykonos and Cyclades guide has the harbour-by-harbour version.
France draws its line at 24 metres
In French Mediterranean waters, length changes the regime and not merely the paperwork. A 2019 framework order from the maritime prefect set the principles for where vessels may anchor and stop, and local orders now apply it along the coast, organising the anchoring of vessels of 24 m and over — 20 m and over in parts of the Alpes-Maritimes — for safety of navigation and to protect the posidonia meadows. Off Pampelonne, between the Pointe de Bonne Terrasse and the Cap du Pinet, that means mooring zones assigned by vessel length, plus drop-off zones where you may land guests and do nothing else. The prohibited areas are charted on the official French charts every boat is required to carry, and they are enforced afloat.
The seagrass rules themselves are not a big-boat rule — posidonia is protected whatever you are driving. Put current French charts aboard before a Riviera summer and check the zones that apply to your length. Where the hook can go down has changed more than the boats have, and our Mediterranean anchoring run walks the permits and reservations that now shape the week.
Riva's 76' Perseo Super is the interesting case here. It measures 23.25 m — 76 ft 3 in — which leaves it three-quarters of a metre under the line. It carries 1,479 US gal (5,600 L) on an 18 ft 10 in (5.75 m) beam and 6 ft 3 in (1.90 m) of draft, and on the MAN V12-1550s it cruises 28 knots with a published range of 315 nm; the 1800s lift cruise to 32 knots on the same range. That is a boat that can eat a long day-hop before lunch and still anchor and berth as a sub-24-metre yacht.
Beam buys the day and spends the berth
Aquila's 46 Yacht answers the same water from the other direction: 47 ft 2 in (14.36 m) overall, 23 ft 3 in (7.10 m) of beam, 4 ft 1 in (1.24 m) of draft, 476 US gal (1,800 L) standard with an optional second tank of 211 US gal (800 L), twin Volvo Penta D4 320s, and three-, four- or five-cabin layouts.
Set the three side by side and the trade is arithmetic. The Aquila is 12 ft 8 in shorter than the Ferretti and 6 ft 10 in wider. It draws 10 inches less than the Ferretti and 2 ft 2 in less than the Riva. For the hours a Mediterranean crew actually spends at anchor — and in July that is most of the daylight — width wins outright: more deck to spread across, more shade to sit in, and a draft that opens coves the other two read from further out.
That width is also the thing to settle in advance. Med berthing is stern-to, and a stern-to berth is allocated by the gap between the fingers as much as by the length of the quay, so a boat over 7 m across the beam is a specific conversation with a capitainerie rather than an assumption. Give them your beam when you book a season base, not when you arrive.
What each one is really for
The Ferretti 580 keeps the most harbours on the list: a genuine three-cabin flybridge that still fits under the Cycladic caps and comfortably under the French length line.
The Riva 76' Perseo Super buys speed and a long day — 28 to 32 knots of cruise, 315 nm — and buys it from under 24 m rather than over it, which is what makes the number worth noticing.
The Aquila 46 Yacht is built for the anchored hours rather than the arriving ones: the widest deck and the shallowest draft of the three, on the smallest tank.
One honest gap. Riva publishes a range figure and the other two builders don't, so plan long hops from the tank, the sea state and your own burn rather than from a brochure. In this water that is rarely what bites anyway — a Mediterranean summer is a chain of short passages between harbours that care far more about your dimensions than your endurance.
Tony's Take
I would buy under the line and stay there. Every metre past about 23 opens a file somewhere: a different anchoring zone off the Riviera, a different quay on Mykonos, one more island where the answer is the tender instead of the passerelle. The owners I watch enjoying the Med most are the ones whose boat is a little smaller than their budget and a lot easier to park, and not one of them has ever told me they wished they had gone longer. Buy the boat that gets into the harbour you actually want to wake up in. — Tony Smith, Founder — Minted Yachts
Tell us the harbours you want to wake up in and the weeks you have, and we will tell you which lengths keep all of them on the list — and which extra metre would quietly take three of them off it. Email TS@MintedYachts.com, call +1 (404) 805-9819, or send the brief through the contact form.