Location: Isles of Scilly
Age / period: post medieval (1798)
List entry number: 1000078
Reason for designation: historical significance
Wreck history and loss
'HMS Colossus' was a 74-gun warship built in 1787 at Gravesend by Clevely, and wrecked off Samson in the Scillies in 1798. These 74-gun ships were one of the most successful types of the period. They were typically about 51m (170 feet) in length and had a compliment of approximately 600 men. During her relatively short working life (11 years), 'HMS Colossus' saw action at Toulon, Groix and Cape St Vincent.
In December 1798 she was on her way home to England with wounded from the Battle of the Nile and a cargo, including Sir William Hamilton's collection of Etruscan pottery. She was sheltering from a gale in St Mary's Roads when the anchor cable parted and she was driven aground south of Samson. All but one member of the crew were taken off safely before 'HMS Colossus' turned onto her beam ends and proceeded to break up.
'HMS Colossus' was originally designated under the Protection of Wrecks Act in 1975 when Roland Morris worked on what was probably the bow section of the wreck. He recovered a large number of pottery shards from Sir William Hamilton's collection, which are now in the British Museum. He also recovered a number of other artefacts, including iron cannon. This designation was revoked in 1984. The records relating to this work have so far not been located.
In 2001, the current site was discovered some 350m to the east of Roland Morris' site. Considerable amounts of timber were exposed on the seabed along with a row of five iron guns, standing upright, their muzzles buried in the sand - still within their gunports. Most striking of all was a twice life-size carved wooden figure; part of the stern decoration of 'HMS Colossus', lying face upwards on the sand.
The licensee, Mac Mace, and the Archaeological Diving Unit undertook an excavation in September 2001 to recover the stern decoration. This, however, proved to be too extensive to recover with the equipment available: it was therefore reburied for the winter. The area around the stern of the vessel was surveyed prior to the excavation by means of a photomosaic.
Discovery, investigation and artefacts
1830's Dean Brothers (Bow)
1974 Roland Morris (Stern)
1999/2000 Local Divers
The wreck of 'HMS Colossus' lies to the south of Samson in the Isles of Scilly. There are two main areas of wreckage, lying some 350m apart. In 1975 part of the wreck (probably the bow) was designated under the Protection of Wrecks Act. This designation was revoked in 1984. The current site was discovered by sport divers and designated in 2001.
The site contains a substantial proportion of the wreck of the 'HMS Colossus', part of which is hundreds of metres to the west and was excavated under licence in the 1970s. The degree of preservation of organic material is very good, including outstanding examples of decorative carving from the stern. The exposed carvings are under immediate threat from natural degradation and in situ physical protection may not be the best solution.
The rear half of the port side of a 74-gun ship-of-the-line lies flat preserved in the sand. The wreck includes the six aftermost gun ports on the upper gun deck, five of which still have 18 pound guns pointing through them, with their breech ends uppermost. The ship's structure appears to be complete from the top of the gun ports on the quarter deck down to the turn of the bilge just below the orlop deck.
The site lies at a depth of about 12m. The seabed around and over the site consists of coarse, white sand with fine crushed shell. Timber elements of the wreck are currently exposed on the seabed. This exposure is recent (otherwise the timber would have decayed) and appears to be due to ongoing erosion of sand from the site.
The fabric of the vessel is remarkably well preserved; however once it is exposed, deterioration due to biological decay is fairly rapid. The timbers of the vessel are being exposed due to the sand of the seabed being eroded. The precise reasons for this erosion are not known, but a more detailed discussion of this phenomenon is presented in Appendix III of the 2002 survey report.
The deterioration in the exposed timber in the 12 months between discovery and final survey was marked. Timbers which appeared perfect in June 2001 were visibly gribbled and decayed by June 2002. Once the timbers are weakened by biological attack they will be subject to detachment and dispersal by the tide and wave surge during winter storms. The current English Heritage funded Site Stabilisation Research reported in September 2005.
The disposal of the recovered stern carving is being dealt with by the Receiver of Wreck. The stern carving is now undergoing conservation.
In 2009 English Heritage funded a dive trail on the site to allow visiting divers to learn more from their visit. For more information please visit the dive trail webpages.