As defined by the Royal Navy Hydrographer: the River Severn extends down to the Second Severn Crossing; the Severn Estuary is the area between this bridge and a line from Lavernock Point (south of Cardiff) to Sand Point near Weston-super-Mare. West of this line is the Bristol Channel; (note different coastline shading on chartlet)

For the small motor boat sailor, it is more realistic to include in the definition of the Estuary, all the area south of Sharpness.

Once you have locked out of Sharpness, you are in fiercely tidal waters!

Given fine weather and an understanding of the tides, it is feasible for small boats to make a passage between Sharpness and Bristol or Cardiff and beyond.

Approximate passage distances from Sharpness are 24 nautical miles to Bristol and 38 miles to Cardiff.

The navigable channel is well marked with beacons and buoys but involves many changes of course.

Tidal currents in the Severn Estuary are very strong (upto 8 knots at Springs) and rocks and sandbanks abound.

Your boat should be equipped for a coastal passage with emphasis on good ground tackle and adequate safety gear.

The relevant charts should be carried.  Small craft should seek advice from the Harbour Masters at Sharpness, Bristol or Cardiff.

	Avonmouth marks the entrance to the River Avon and the Port of Bristol. It is a busy shipping area and a full knowledge of navigation and the rules of the road is required. The River Avon, with access to Bristol marina, is navigable only at certain states of the tide.
Avonmouth Pierheads

Portishead Pier a short distance south of Avonmouth offers a convenient anchorage, except in northeasterly winds, and a marina accessible at most states of the tide. The view is from the marina lock looking toward the Severn Estuary at low tide. An anchorage in water is available just north of the pierhead.
	Portishead Pier from marina lock

The Cardiff Barage encloses the wide Cardiff Bay.  Cardiff (Penarth) marina is inside the barrage. It is accessible except at very low tides through one of three locks and bascule bridges. This view is from the outer basin on the Severn Estuary / Bristol Channel side of the barrage.
	Entrance locks Cardiff

	It is common practice for inexperienced crews to hire a pilot on these waters especially for the passage between Sharpness and Avonmouth.
Code Flag G.....I require a Pilot