Choosing a boat slip—especially when it comes to long-term moorings—is a decision that deserves careful consideration. There are, in fact, quite a few factors to take into account when choosing the ideal marina for your boat, and we’ve actually already published in-depth guides on selecting the perfect marina. One thing is certain: among the essential requirements that simply cannot be compromised is a berth large enough to accommodate your boat. More specifically, the body of water you’re considering should be wide enough to allow for easy maneuvering when entering and exiting; but not so large that you end up paying a berthing fee that ’s excessive compared to your boat’s actual needs. But what should the actual size of the berth be? It is, of course, the ports that offer the most suitable berths on a case-by-case basis based on the dimensions of the boats, while also taking into account the characteristics of the berth itself (with fixed or floating docks, with or without a gangway, and so on). However, it can be helpful to understand the criteria marinas use to assign berths based on the size of the hull!

Choosing a Boat Slip: Before Considering Size

Of course, even before considering the size of the berth, in order to choose the perfect mooring—perhaps within the same marina—you need to make sure that other requirements are met. What’s the point of making sure the berth’s length and width are sufficient, only to discover that the maximum draft in that particular area is insufficient to ensure the boat doesn’t touch the seabed at low tide? And this is just one of the considerations that should be taken into account. Consider, for example, those looking for a berth for a superyacht—that is, a vessel over 30 meters—or for a megayacht, over 60 meters. Some ports with sufficiently long docks and ample draft could potentially offer berthing for these large vessels, but they do not, knowing they cannot provide the yachts with even basic services: think of the availability of electrical outlets with high amperage, proximity to fueling stations, facilities for the crew, and so on.

So yes, making sure that the marina you want has a berth that’s large enough is essential, but it’s never the only factor to consider when making your choice. With that said, let’s move on to how to calculate the size of a berth.

Berth Dimensions: The Required Clearance

Mooring a boat isn’t like playing Tetris. Even the most skilled recreational boater, the most meticulous and patient skipper, the most experienced captain, and even a yacht equipped with the most advanced automatic mooring system—they all need a little leeway to perform their maneuvers. But exactly how much clearance should there be between the hull and the dock? There are no set rules, although , to be honest, there are several technical recommendations for designing welcoming and safe ports, including guidelines for the minimum dimensions of berths.

That said, as a general rule, it’s always best for the size of the berth—and we’re talking about small or medium-sized berths— to be 10 or 15% larger than the boat’s current length, and 10 or 20% larger than its maximum beam. As mentioned above, it all depends on the type of berth as well: the difficulty of mooring changes if, for example, there is a cushioned finger alongside our boat instead of another vessel.

Let’s consider a boat slip designed to accommodate watercraft, with a water area 3.5 meters wide and 10 meters long: to ensure easy maneuvering and to avoid creating difficulties for other users crossing the adjacent channel, it would be best to reserve that spot for boats with a maximum length of 9.5 meters and a maximum beam of 3.2 meters—and even better for boats that are slightly smaller.

Or, let’s look at it the other way around, assuming we need to find a berth large enough to accommodate a superyacht 29 meters long and 7.3 meters wide, such as Azimut’s fantastic Grande 30M: the ideal berth would need to be at least 35 meters long, with a width of at least 8.5 meters.

In addition to the boat slip: keep an eye on the space on land

Anyone who has never given much thought to the nature and operation of modern marinas might assume that, in a marina, the only thing that matters is the size of the berths—that is, the bodies of water available for mooring. However, that’s not really the case: as the number and area of berths for boats increase, the amount of space on land should also grow. That’s because every port, in order to provide good service to boaters, must have sufficient onshore areas—think of parking lots for cars and for boat trailers, which should be available in sufficient numbers (in proportion to the number of berths), be large enough, and preferably located nearby. But let’s also consider maneuvering areas, spaces designated for restrooms, areas equipped for dry storage or maintenance operations, and so on. In short, when choosing a port for your boat, it’s always a good idea to consider the size of the onshore areas as well, rather than focusing exclusively on the docks.

Marina Porto Antico, berths for yachts and superyachts in Genoa

Marina Porto Antico offers 270 berths to recreational boaters who wish to moor in the center of Genoa. These include 5 berths for superyachts up to 35 meters, 2 berths for maxi-yachts up to 40 meters, and, finally, one berth for megayachts up to 75 meters. Are you looking for the perfect spot for your boat? Contact us to reserve it!