ICCE 2016 Cover Image


Tristan da Cunha
Calshot Harbour
emergency breakwater repair
physical modelling

How to Cite

Bouton, P., Van Eeden, F., Retief, M., De Roubaix, F., & Kieviet, J. (2017). EMERGENCY REPAIRS TO THE MAIN BREAKWATER OF CALSHOT HARBOUR ON TRISTAN DA CUNHA ISLAND. Coastal Engineering Proceedings, 1(35), structures.50. https://doi.org/10.9753/icce.v35.structures.50


The breakwater at Tristan da Cunha suffered structural damage during heavy seas that battered the island during winter 2010 (June and August). The damage was of such a nature that emergency repairs had to be designed and constructed before the onset of the next winter season. The damage entailed the loss of primary armour units (3.5t dolosse) at the head of the western breakwater exposing the under-layer rock as well as some slight movement of the end section of the crest slab (cap). Further damage to the breakwater head (130m offshore in 6m water depth) was reported one month later; with the crest slab being lifted further by approximately 500mm. The construction methodology during the emergency repair design process, laboratory validation and onsite construction is covered in this manuscript.


CIRIA, CUR, CETMEF (2007). Rock Manual. The use of rock in hydraulic engineering. (second edition). C683, CIRIA, London.

CSIR (2010), Roundhead Repair Stability Test for Tristan da Cunha Harbour, Quasi 3D Physical Model Test, February 2011, Stellenbosch, South Africa. Report number CSIR/BE/IE/ER/2011/0005/B.

Halcrow (2005) Tristan da Cunha - harbour construction. Final Report. Halcrow group Limited. March 2005.

Hughes, S.A., 1995. Physical Models and Laboratory Techniques in Coastal Engineering, World Scientific, Singapore. ISBN-10: 9810215401.

Phelp, D. & Tulsi, K., 2006. Digital Image Technology as a Measurement Tool in Physical Models, Coastal Lab 2006 - 1st International Conference on the Application of Physical Modelling to Port and Coastal Protection, Porto, Portugal.

Phelp, D & Zwamborn, J. A., 2000. Correlation between Model and Prototype Damage of Dolos Breakwater Armouring, Coastal Engineering 2000 - 27th Conference on Coastal Engineering, Sidney, Australia.

Tritan Survey cc. (2010). Calshot Harbour Survey. Tritan Survey cc.

Vonk, R., Phelp, D., Boysons, C., Edries, R., 2007. Survey of the old dolos breakwaters, Tristan da Cunha, Coastal Structures 2007 - 5th International Conference, Venice, Italy, 92 - 103.

Webb, R. M. (1999). Tristan da Cunha Harbour Development Pre-Feasibility Study Final Report. Colchester: Robin Webb Consulting Limited.

WSP (2010), Tristan da Cunha - Calshot Harbour Interim Final Assessment Report, October 2010, WSP Africa Coastal Engineers, Stellenbosch, South Africa.

WSP (2011), "Tristan da Cunha - Calshot Harbour Final Assessment Report†, WSP Africa Coastal Engineers, Stellenbosch, South Africa, April 2011.

WSP (2012), Defects Liability Inspection Report, 2010/11 Temporary Emergency Repairs on Tristan da Cunha Breakwater, June 2012, WSP Africa Coastal Engineers, Stellenbosch, South Africa.

Authors retain copyright and grant the Proceedings right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this Proceedings.