HMS Colossus

Investigation and Monitoring 2012



Charles Galley

CISMAS divers recording during the excavation of Colossus in 2012




A small excavation was undertaken on the stern section of the designated wreck site of HMS Colossus. There were a number of reasons for this undertaking: investigation of the main gun deck ordnance, recording of a main gun deck port, and detailed recording of the post-wrecking stratigraphy present on the wreck. In addition to these site specific enquiries, a number of more general aims were achieved. These include investigation and appraisal of different excavation methods and recording regimes, and the initiation of a long-term reburial trial on the site using real archaeological objects rather than modern tokens. Finally, an opportunity to gain experience in underwater excavation was offered to two separate ‘trainees’, who were able to use their experience towards their NAS part II or III qualifications.

The Site

Colossus site plan showing the position of the excavated trenches


Four new trenches were planned for 2012, however, due to bad weather the last trench (trench 6) was not excavated.


Trench 3

Trench 3

Plan showing part of the orlop deck excavated in trench 3 


This trench was located on the orlop deck of Colossus between two hanging knees. The hull in this area was lined with lapboard planking. The lapboard lining attached to the hull and hanging knees suggests that the space between the two hanging knees was used as a small cabin or storeroom. The aft of the orlop was often used for small cabins for the purser, surgeon chaplain etc. A number of store rooms were also often situated here such as the slop room and the stewards’ store.

Trench 3 Section
Trench 3

Trench 3 (scales = 0.5m)


Trench 4

Trench 4

This trench was located on the main gun deck (MGD) of Colossus between two hanging knees. The main feature located in trench 4 was a main deck gun port. The port was 1.05m wide, 0.85m high and 0.60m deep (through the thickness of the hull). The port lid, hinges and the gun were missing. The main gun-deck armament consisted of 32lb Blomefield pattern guns, which were 2.9m (9’ 6”) long and weighed 2.8 tonnes (56cwt). Three of these guns  have been found in the Colossus debris field  but to date none have been found on the wreck itself. This raises an interesting question – why when the six upper gun deck 18lb guns are all still in place on the site are none of the MGD 32lb guns still on the wreck? Certainly, in the case of the gun port in trench 4 it would seem that the gun probably exited through the gunport, removing the port lid and hinges as it did so – few other scenarios would account for the missing port lid.


T4 Section

North-south section through trench 4 showing the layers encountered.


Trench 4

Blocks and ropes associated with the (now missing) gun were found in this trench. A detailed study of these can be found in the project report download here


Above: a north south section through the gunport in trench 4.

Below: showing how the gun and carriage would have sat in the gunport when the ship was upright – note the ‘stop beam’.

T4 Gun


Trench 5

Trench 5

This trench was located on the orlop deck of Colossus between two hanging knees. It was situated immediately to the west of trench 3, which was also on the orlop deck and was excavated before trench 5.
Unlike the adjacent trench 3 (also on the orlop deck), there was no lapboard lining in trench 5. Thus the inner hull planks were all visible in this trench – except where obscured by the iron concretion (fig 39). The lack of lapboard (as seen in trenches 1 and 3) suggests that this part of the orlop was either not partitioned off, or was not required to be kept as dry as the lined sections.
Perhaps the most interesting of the objects recovered from trench 5 were several objects relating to tools, perhaps pertaining to carpentry. The most notable of these was F779, a wooden draw plane or spoke shave found in layer (L32). Also from this layer came a pewter vessel possibly containing the remains of a brush – perhaps a glue pot. Both these objects are undergoing conservation and investigation at York Archaeological Trust (YAT) and will eventually go on display at the Isles of Scilly museum.

Trench 5
Trench 5


Excavation and reburial trials were undertaken
25th May – 8th June 2012

Monitoring and Survey was undertaken
21st-28th September 2012

If you would like further details the Project Design (PD) can be downloaded here

The project report can be downloaded here