The weekly rate in the listing is the beginning of the price. On top of it comes the advance provisioning allowance, usually 30 per cent of the rate, which pays for fuel, food, drink, berths and everything the guests consume; it is an estimate, settled at the end. Then VAT at the rate of the country where the charter starts, and a gratuity for the crew of 10 to 15 per cent in the Med and 15 to 20 in the Americas.
A week is also a distance. A 50 metre motor yacht cruising at 12 knots covers about 60 miles in a comfortable morning, so a Riviera week runs Monaco to St Tropez to Corsica and back, an Ionian week runs Corfu to Lefkada and the islands south, and a Virgin Islands week hardly moves at all. The best itineraries are short on miles and long on anchorages.
Seasons decide everything. The Med runs June to September with July and August at full rate, the Caribbean December to April with Christmas and New Year at a premium and a minimum of ten nights, and the shoulder months on both sides are where a well-advised charterer goes.