Portumna round Lough Derg

Le Boat's base is in Connacht Harbour, on the upstream side of Portumna Bridge, so your first job is to catch an opening of the swing span. From April to September it opens Monday to Saturday at 10:00, 11:00, 12:30, 14:30, 16:00, 17:30 and 18:30, and on Sundays at 10:00, 11:00, 12:30, 14:30, 16:00 and 17:00; wait at the floating jetty above it. If you miss the last opening, stay in Connacht Harbour, which is public. Then it is a short run onto the lake to Terryglass. Moor along the inner walls of the harbour; the outer side is lively in a strong wind. Paddy's Bar and The Derg Inn both serve food and host music.

Before you leave, take a look at Old Court, the four-towered castle built beside the harbour between 1219 and 1232; it is a national monument, seen from outside only. Terryglass has no pump-out, so empty the tank at Dromineer. Today's run south to Dromineer is about 22 km of open lake, so read the forecast first and keep to the marked channel. Dromineer has a public marina with floating jetties, shore power and a pump-out, and a new building with showers paid by tapping a card. The Whiskey Still is a few steps from the berths, the beach beside the harbour is an official bathing water, and the RNLI's Lough Derg lifeboat is based here.

Garrykennedy lies on the way south, so stop there for lunch: the floating jetties outside the old stone harbour suit visiting cruisers, and Larkins, a thatched bar two minutes away, is known for food and traditional music. This is open water, so check the forecast before each leg. Then follow the lake as it narrows to Killaloe & Ballina, where public jetties lie above the old bridge on both banks. Stay above it: it is the lowest bridge on the main Shannon. St Flannan's Cathedral, from about 1200, is open daily, and pubs, restaurants and supermarkets are a short walk from every berth.

Head north up the Clare shore: open water again, so check the forecast. At the head of Scarriff Bay the lake gives way to the winding, tree-lined Scarriff River. On a sharp bend you pass Reddan's Quay at Tuamgraney, where a restored lime kiln stands by the water; St Cronan's Church, ten minutes' walk away, has parts from the 10th century and a claim to be Ireland's oldest church in continuous use. Scarriff harbour has concrete finger berths, so there is usually room, plus water, shore power, a pump-out, toilets and showers. The town, fifteen minutes on foot, is a good place to restock: supermarkets, a butcher, a pharmacy and the Garden Café at the community co-op.

A short morning hop down the river and along the bay. Arrive early, because Mountshannon harbour is one of the busiest on the lake on summer evenings; it has berths on the wall and on floating jetties, shore power, a pump-out, toilets and showers. From April to September a guided boat leaves the pier daily, weather permitting, for Inis Cealtra, the monastic island with a round tower and six ruined churches; there is no need to book. The Inis Cealtra Visitor Experience in the Old Rectory tells the story first, and has a café upstairs. The Blue Flag bathing area beside the harbour has lifeguards in summer.

Run east along the Clare shore to Dromaan Harbour, just south of the private marina at Williamstown. This is open water again: check the forecast and stay another night in Mountshannon if it is rough. Dromaan is a small, very sheltered council harbour where boats lie against the wall or in concrete finger berths. There are toilets and showers but no pump-out or shore power, so empty your tank in Mountshannon before you leave. It is a quiet rural stop: Whitegate, a couple of miles inland, has The Half Barrell pub with home cooking and traditional music, and is a trailhead of the East Clare Way.

Back up the lake to Portumna, keeping to the marked channel; read the forecast first, and if the wind is strong, wait in Dromaan for it to ease and let the base know. Time your arrival for a bridge opening, since the base lies above the swing span. If you are early, tie up at Castle Harbour, the public lake harbour beside the castle demesne, and walk up to Portumna Castle, an early 17th-century house of the de Burgo earls with formal and walled gardens, or into the forest park. The Irish Workhouse Centre runs guided tours from March to October. Then take the next opening through to Connacht Harbour and hand the boat back.