As you go further up the river, both banks are lined with rafted boats. Thousands of them, up to four in each raft. This picture is taken at the eastern end of the isola which runs for about 1.5km in the centre of the river, and ends just before the main motorway bridge which closes the river to anything sporting a mast.
The isola itself has yachts rafted along it. We went up the north side of it, and chickened out of the south side when the depth got to 5m even before we entered the channel proper. Otherwise we carried at least 6m pretty much all the way to the bridge.
Most of the yards lining the banks are private, many of them clubs. You might wangle a berth for a while with fluent Italian and good connections, neither of which we have. We had booked ourselves into Nautilus Marina, about a third of the way up the island, on the north bank. We arrived just before dark and were told to raft to a boat and we'd sort out the paperwork in the morning. In the dark, the place was rather eerie. We found the toilets, but no shower. Only one other boat (a posh motoryacht on the hard) seemed to have anyone aboard. A peek outside found a busy road with no signs of shops, houses or any other life.
In the morning we met the helpful Oliva, with whom we had been exchanging emails. How do we get into Rome? Ah - you go the bridge, about 2km away, and get the bus. And to get to the bridge? Walk, or take the dinghy. Laundrette? No. Shower? No. Clearly this would not be an easy place to spend much time. It's not their business model: these marinas are really boat warehouses, where nobody expects to spend their leisure hours. Instead they untie their lines and go. It's a shame really as it's quiet, very sheltered and the island is pretty. No-one seemed to be anchored anywhere in the river, which isn't that wide; it would need a mooring to reduce your swing, and we don't know if it is permitted.