WRECKS OF CAERNARVON BAY

Flanked to the east by the rugged coast of Anglesey and to the south by the spectacular mountains that form a spine along the Lleyn Peninsular, Caernarvon bay must lay claim to being one of the most dramatic areas in which to spend a weekend diving - and its not just the above water scenery that attracts divers. From old sailing ships which passed through the Menai Straits on their way to Harlech to modern bulk carriers heading for Liverpool, the bay is littered with wrecks representing generations of shipping. Although regularly visited by large numbers of divers, most people either converge on Anglesey to dive the well known sites that can be reached from Trearddur Bay and Rhoscolyn or they tend to do the same old shore dives and reefs along the Lleyn. Wrecks such as the Primrose Hill, Norman Court and Missouri have kept divers busy for many years, but they are all shallow water sites and tend to be wreckage rather than wrecks. To get to the better sites you need to be able to get off shore.
One of the deeper wrecks in the bay is the tragic remains of the British submarine H5. The H class submarines were ordered as part of the huge naval expansion plans at the outbreak of World War I. Based on a US Navy design the submarines were built in US yards, however to get around American neutrality the ten boats were then assembled at the Canadian Vickers yard in Montreal. The H class had a displacement of 434 tons submerged and dimensions of 45.8m x 4.7m x 3.8m. They carried a complement of 3 officers and 19 men.
On 26 February 1918 the H5 set sail for the Irish Sea, under the command of Lt A W Forbes, DSO. Her orders were to patrol a 10 mile line that extended east from the Caernarvon Bay Light ship. Also aboard was Ensign E F W Childs of the United States Navy who was there as an observer. The patrol was due to return to Bearhaven in Southern Ireland by 09:00 on 2 March. This was an experienced crew, no less than five of which held the Distinguished Service Medal, however when the deadline for her return passed the ship was posted as missing presumed lost. On 6 March the Steamship Rutherglen pulled into Holyhead harbour and her master reported having rammed a U-boat on 2 March, stating that the craft had crossed his bows at 'considerable speed'. A number of men were seen in the water but no attempt had been made to rescue them.
It was decided not to tell the crew of the Rutherglen that the 'U-boat' they had rammed was in all probability H5, as the Admiralty depended on the merchant fleet to take decisive and aggressive action against U-boats. Ensign Childs had the dubious honour to be the first American serviceman to be killed in the First World War. Four months later the Rutherglen became a victim herself, sunk in the Mediterranean by UB50.
H5 was located by Chester diver Keith Hurley in 1990 when freeing a trawl net from an unmarked obstruction. Today H5 sits upright on the seabed in between 58 and 62m in the scour with about a 30° list to port and forms a spectacular underwater monument to the bold submariners who tragically lost their lives on her.
The conning tower is a riot of colour being thickly covered in orange and white plumose anemones as well as being home to numerous shoals of bib and whiting. The semi-circular steps which climb up the side each has its own resident edible crab. The periscope is still extended away from the submarine and just forward of its base is the sad sight of the open main hatch from which the crew had scrambled, after H5 had been rammed, in a vain attempt to save themselves.
The shallowest depth that it is possible to find the top of the conning tower in is 50m on a low water spring - if you're not using extended range diving procedures then it really will be a quick look and then up. Tides can also be a problem as slack on the surface can be running at a knot or more on the bottom. H5 is probably best dived just coming onto low water slack. She is a war grave and due respect and consideration should be paid by anyone visiting her.
If H5 is one of the deeper wrecks of the bay, then to the north lie the remains of one of the largest wrecks - the steam ship Roanoake. Having left Antwerp in ballast the 2000 ton ship was making her way to New York. Having first headed west along the English Channel she turned into St. George's Channel to head north. It was January 1945 and WWII was nearing its final bloody end. The Roanoake's crew felt secure in the knowledge that the Irish Sea was being combed on a daily basis by ships and aircraft on anti-U-boat patrols. However the crew of the U1055, a type VIIc commanded by Oberleutnant Rudolf Meyer, were still taking the war to the allies and caught the Roanoake by surprise with a spread of torpedoes.
The Roanoake burned brightly for several hours and acted as a marker for a sole Liberator aircraft on patrol but no contact was made with the U1055 and the U-boat managed to slip away from the scene (she was later lost with all hands on a north Atlantic patrol). Despite the best efforts of the damage control parties the Roanoake slipped beneath the frigid winter water.
Today the Roanoake sits upright on a seabed of shingle and broken shells which allows for generally good visibility (5 -10m) given the fact that general depths on the deck tend to be around 40m. Her overall size and maximum depth (50m) means that she makes an ideal extended range dive. The tides can be quite critical on her (on one particular dive it was unnerving to be greeted by our two 5 gallon shot drums at 15m as we ascended a near horizontal shot-line). An ideal dive would be on a low water neap tide.
The bows of the wreck are largely intact and very impressive. Large capstans and anchor handling systems are easily recognised. Swimming away from the bow you come to the steel framework and plates of an anti-aircraft station fitted to most American cargo vessels of this vintage. The rotating gun mount is still in place but the gun has long gone. The steel plating is very fragile and probably won't survive many more seasons, especially with divers who insist on pulling themselves around on it. Further aft you come across the first of the cargo holds which is silted up and, as with the other holds, generally not that interesting.
Amidships there is a great deal of twisted and mangled plates and girders. Undoubtedly this area is where the torpedo struck, but the damage seems quite substantial for a single torpedo so perhaps a boiler has exploded as well. The main points of interest on the three deck levels are the railings, lifeboat davits and companionways. Due to the strong tides much of the silt and debris is inside the wreck and any diver considering even a short penetration should not enter the wreck unless using a line, even then it is extremely hazardous. You will have zero visibility as you head back out. The Roanoake makes a great extended range dive, a 40 minute bottom time on air pulls about the same amount of decompression on EANx 70, giving you a good chance to see the wreck, although it would take several dives to fully appreciate her.
As well as the numerous shallow water wrecks which you can do as a second dive, one interesting alternative are the underwater 'sand dunes' that stretch from Trefor on the Lleyn peninsular south-westerly towards Porthdinllaen. The dunes are only a couple of miles off-shore and the average depth around them tends to be about 25m. They vary in height but generally they are 3-5m peaks and troughs. On a recent drift dive on the sand dunes divers reported seeing large amounts of marine life sheltering in the different troughs. Huge shoals of sand eels and crabs where seen in one, large families of dog fish in another, thornback rays in yet another. Definitely worth a visit.
About eight miles out from the Lleyn lies a very picturesque little wreck. The Sigontium was a converted mussel dredger about which very little is known, apart from the fact that she sank about thirty years ago. During her working career her role would have been to gather marine life and that hasn't ceased now that she sits on the seabed.
The Sigontium is home to thousands of fish. During a recent dive on her there were so many juvenile fish (mainly pollack and codling) that the wreck resembled one of those Red Sea wrecks surrounded by shoals of glassfish. As she isn't such a huge wreck and sits upright it is possible to swim the full 30m length of the ship in a single dive. The sea bed reaches 32m in the scour but the general depths on the wreck are about 25m with her single mast rising to 18m. The raised forecastle has all the normal anchor handling gear as well as a huge single winch used for hauling loads out of the fish hold. Every inch of the wreck seems occupied by some form of marine life or other - large crabs jockey for the best spaces, lobsters and conger compete for the available holes while large pollack cruise by looking for an unwary snack. All this marine life hasn't gone unnoticed by the angling community. Anyone diving the Sigontium should be prepared for (and expect to be snagged in) fishing line. Plan for it and take appropriate action. Towards the stern of the wreck is the raised wheelhouse, accommodation and a single funnel. Most of the fittings are long gone yet a few small portholes are still there...if you look hard enough.
Behind the funnel is the frame of the engine room skylight through which you can shine your lights down into the gloom below, but the tight framework makes it impossible to enter the engine room from this direction. Over the gunwhale and on the seabed you can see the little steel rudder, though where the prop would be is wrapped and covered in heavy fishing net. Further net is to be found hanging over the port side of the wreck around amidships. Returning up and over the port side it is possible to make a few short penetrations of the fish hold and also the forecastle though the ever present thick layers of silt will be kicked up very easily.
As stated earlier, there aren't that many large intact wrecks in shallow water, but having dived the Roanoake or H5 as a first dive, steam south easterly or easterly respectively towards the coast at Newborough for a pleasant surprise. Lying in a maximum of only 12m of water are the remains of a large Maltese 'animal oil' tanker the Kimya. This is the perfect dive on which to continue to off-gas and at the same time have a good old ferret about.
The tanker ran aground during the winter gales of 1992 and subsequent salvage has removed most of her superstructure yet it is still quite easy to orientate yourself around her. Finding the wreck is very simple as the bow section breaks the surface at low water. A central pipe and framework runs the length of the wreck so it is very simple to work out when you are crossing the deck port to starboard. Inspection hatches that once led down into the tanks are open and you can peer inside them (they are too narrow to climb or drop through).
There is a doorway on the starboard side that leads back inside the bow. Here there is a good clearance between ceiling and floor and an excellent penetration can be made into the large bow. Having tied off by the valves at the door entrance swim forward and slightly to the right to find the entrance to the chain locker that puts you in only 2-3m of water! Several large lobsters live in this area one (at least 5lb) living under walkway grating that has fallen to the floor forming a perfect cage above his lair. Having reached a bank of silt that blocks further exploration it's time to follow your line back through virtually nil visibility to the entrance.
There are several other good swim-throughs on the wreck around a central accommodation block and in the area of the smashed up engine room. Expect to see large shoals of pollack, bass and mullet as well as spider and large edible crabs. Some areas are covered with thick juvenile mussel beds on which abundant starfish graze. The visibility is never brilliant (3-4m on average) but the shallow depth allows you the opportunity to take your time and slowly work things out. With wrecks from 3 to 63m and a multitude of marine life, Caernarvon Bay has something for everyone and if the weather's bad you can always head into the Menai Straits .... but that's another story.

By Ron Mahoney.