Still under construction at the outbreak of World War Two, the 9600 ton Port Napier was requisitioned and converted for mine-laying. It was loading mines at the Kyle of Lochalsh on 27 November, 1940 when fire broke out on board.
The ship was towed out into the loch just before an explosion sank it; debris can still be seen on the nearby shoreline. Surprisingly, none of the mines exploded and have since been removed.
The Port Napier now rests in 16 metres on its starboard side, with the port side projecting clear of the surface at all but high water.
It is this combination of sheltered location, unusual purpose, shallow depth and salvage history that makes the Port Napier such a magnificent dive. Even deep inside the wreck, shafts of daylight enter from above through the many openings cut in the hull.
Before beginning the tour, it might help to go through a few peculiarities of the construction of the Port Napier. Although the basic layout follows that of a more conventional freighter, the conversion for mine-laying connected the holds by internal narrow-gauge railway lines on either side of the ship.
Each mine comprised two main parts: the classic spherical mine with horns, and a combined anchor and cable assembly. The anchor was fitted with wheels to make a trolley that could be run along the railway inside the ship.
Mines were stored in sidings beneath decked-over holds. To lay a mine, the complete assembly would be pushed along the railway and out through hatches located just above the waterline on either side of the stern of the ship. The trolley would sink to anchor the mine to the seabed, the cable would unwind and the mine would float at the set depth.
With the port side of the wreck standing clear of the water, it is easy to begin a dive on the Port Napier right up at the bow (1). Below the bow, cables hang and stretch back to the keel (2). It is hard to tell what their purpose was, but nowadays they are host to some very long and delicate plumose anemones.
Right at the front of the bow one can look back along both the upper port and lower starboard sides of the hull. The sunlit port side is a forest of sugar kelp and the shaded starboard side a garden of delicate anemones and tunicates.
Back on deck, the original wooden decking is still reasonably intact. A pair of 4in guns dominates the bow deck (3). The starboard gun is at a depth of 11 or 12m and slightly forward of the kelp-covered port gun.
Just behind the guns, the forward mast (4) has an interesting pulpit-like structure located just above the deck and a more obvious railed platform near the top of the mast.
Behind the mast, the deck steps down with open doorways back beneath the bow deck to the forward hold (5). A large deck hatch provides easy access to the No 2 hold (6), separate from the mine-laying railway system and open to sunlight from the port side.
Next, the superstructure projects across the seabed (7). Open doorways and windows again allow easy access inside. Considering the magnitude of the explosion that sank the Port Napier, the area of the wheelhouse is surprisingly intact but, just behind it, the structures that would have been above the engine room are a tangled mess. All that is recognisable are the remains of the funnel collapsed forward and resting on the seabed (8).
Continuing aft, the deck drops one level to the decked-over No 4 hold. Littered on the seabed is a pile of mine anchors (9), easily recognisable as over-sized porta-potti toilets on wheels. Inside these are drums for the mine tether cables that would have been attached to mines resting in the bowl-shaped indentation on the upper side of the trolley.
The deck above the No 5 and 6 holds is again one level lower. This is a relatively featureless stretch of deck planking, broken by winches and masts. From a photographers point of view, cables dangling from the top of the aft mast (10) to the seabed caught my eye, again covered in long and delicate plumose anemones.
The aft deck rises one level above again. Open doorways (11) provide easy access to the cabins inside. Near the seabed, an interesting feature is a large power capstan (12).
Actually on the centreline is a structure set into the deck that could have been the base of another gun mount (13). The Port Napier is documented as carrying four 20mm anti-aircraft guns, but no sign of these remains.
While at the stern, take a short diversion to view the keel and the two propshafts projecting on either side. If you are interested in the mine-anchor trolleys, off the stern on the seabed lies an isolated intact and upright specimen (14), conveniently placed for closer inspection.
Below the stern railing are the mine-laying hatches. If you are not into wreck penetration, just have a quick look at the railway lines inside these hatches, then enjoy returning to the bows along the outside of the ship. With a 9600-ton wreck, there will be plenty to see that you missed on the journey to the stern.
If you want to venture further, make sure you take the normal precautions for wreck penetration. The railway lines can be followed through junctions and sidings past trains of mine anchors. Every so far, shafts of light spray down through holes cut in the hull of the ship, providing convenient exits upwards (but watch your hands on the sharp metal if you decide to climb out).
From the No 3 hold, you can exit via a short passageway and a bowed bulkhead into the open No 2 hold in front of the superstructure (6).
The Port Napier is not one of Scotlands most dived wrecks, but everyone I know who has dived it reckons it should be. It is a dive you will never forget. Remember to take a twinset - not for the depth, but for the safety it offers when penetrating the wreck and for the hour-plus dive time you will no doubt want to make. And make sure you go soon, because a commercial salvage company is investigating scrapping the wreck for radiation-free steel.

Would your club or dive centre like to see its favourite wreck featured here If you would like to help John Liddiard put together the information for a particular wreck, why not invite him to come and dive it with you Write to John c/o Wreck Tour at Diver.

To describe HMS Port Napier as a floating bomb when she was tied up to the pier at Kyle of Lochalsh on 27 November, 1940 was almost an understatement. Just loaded into her six holds were 550 sea mines and 6000 shells for her 10 anti-aircraft guns, writes Kendall McDonald.
Port Napier, 498ft long with a beam of 68ft, was being built as a cargo steamer for the Port Line when she was taken over by the Government and converted to a naval minelayer during the final stages of her construction.
The loading of mines into the new ships holds had just been completed when a fire broke out aboard. All efforts to put it out failed and the blaze grew larger and larger. The evacuation of the people of Kyle and of Kyleakin on Skye on the other side of the narrow neck of Loch Alsh began at once.
Everyone in the naval base realised that when Port Napier blew up she would level every house within miles. Despite this, Navy tugs pulled her well out into the loch before casting her adrift. Moments later, a massive explosion blew part of her sky-high and bits of superstructure landed on the shore of Skye. But, amazingly, none of the mines went off.
The ship tipped over on to her starboard side and sank. Her port side just showed above water. There she lay with her mines until 1955, when a Royal Navy salvage team took off most of the plating of her port side and lifted out the mines. Out, too, came 4000 anti-aircraft shells.


TIDES: The Port Napier can be dived at all states of the tide.
GETTING THERE: From Fort William, take the A82 and A87 to Kyle of Lochalsh. From Inverness, take the A82, A887 and A87 to Kyle of Lochalsh. If travelling from the distant south, consider breaking your journey with a day diving the Clyde or Oban. Alternatively, take the train from Inverness to Kyle of Lochalsh, or even fly to Inverness and rent a car and cylinders.
DIVING AND AIR: There are no dedicated dive boats in the area, but local charter boats will take out parties of divers: try Perfect Day, skipper Neil Macrae, 01599 577230 or Sea Cruise, skipper Wally Van-Gool, 01599 534760. The Harbourmaster at Kyle can also put you in contact with local boats, 01599 534167. Dive & Sea The Hebrides at Lochbay near Dunvegan to the north-west of Skye has cylinders and weights for hire and can arrange diving on the west of the island, 01470 592219. Boat skippers can make arrangements to use more local privately run compressors.
LAUNCHING: Disused ferry slips at Kyle of Lochalsh on the mainland or Kyleakin on Skye.
ACCOMMODATION: There are many hotels, B&Bs and hostels which will cater for the large number of backpackers that travel to Skye. In a small town like Kyle, everyone knows everyone else and boat skippers can no doubt recommend suitable accommodation.
QUALIFICATIONS: There is something for everyone, from newly qualified divers through to experienced wreck explorers.
FURTHER INFORMATION: Admiralty Chart 2540, Loch Alsh and Approaches. Ordnance Survey Map 33, Loch Alsh, Glen Shiel & Surrounding Area. Dive Scotland Vol 2 - Dive North-west Scotland, by Gordon Ridley. Shipwrecks of the West of Scotland by Bob Baird. Dive Scotland s Greatest Wrecks by Rod Macdonald. Shipwreck Index of the British Isles Vol 4, by Richard & Bridget Larn. Highlands of Scotland Tourist Board 01997 421160, or on the web at www.host.co.uk/skye/index.html

PROS: A unique wreck with lots to see and explore. Sheltered from all but the most horrendous weather.

CONS: Remote location. Heavy bridge tolls if you cross to Skye.

Thanks to Alex Poole, Jonathan Peskett, Neil Macrae, Gordon MacKay and Aileen Robertson for their help.

Co-ordinates 57 15.95N 05 41.15W (degrees, minutes and decimals). Just about as easy as wreck location can get, with wreckage visible clear of the surface at all but high water.
The wreck is about 300m north-east of debris on the shoreline of Skye. East and west cardinal buoys are a few hundred metres either side of the wreck. Approach with caution, as you could easily hole a boat on the shallow wreckage.