-- FROM AFONDO MAGAZINE --
A recent equipment demonstration done by Simrad Spain detected a wreck which, according to early indications, could be the legendary vessel of the Battle of Trafalgar, the Santisima Trinidad.
Example data from the EM302 installed on the hydrograhic vessel Tofiño operated by the Spanish navy, imaging the Straight of Gibraltar.
Example GeoAcoustics side scan sonar data imaging a shipwreck in great detail (not the Santísima Trinidad in this case, the data has not yet been released by the Spanish navy).
Artist impression of the Santísima Trinidad autorised by its author Carlos Parrilla Penagos.
The Hydrograpic Vessel Malaspina operated by the Hydrograpic Institute of the Spanish Navy.
Last year, staff from Simrad Spain performed a demonstration of a side scan sonar
from GeoAcoustics A Kongsberg Company onboard the hydrographic vessel Malaspina
operated by the hydrograpic institute of the Spanish navy. They decided to do an
in depth study in an area where a KONGSBERG's EM302 multibeam echo sounder, already
installed on the vessel, had previously made some discoveries that called for attention.
The target is in about one hundred meters depth, off the coast of Cadiz in Southern
Spain. Already with the first high-resolution images obtained with the GeoAcoustics
Dual Frequency side scan sonar, it was confirmed that this was a reasonably well-preserved
Driven by the excitement of finding and collating historical data on the sinking
of the Santísima Trinidad, the team registered and recorded numerous side scan records
in order to supply data to the University of Cadiz. The latest reports suggest that
this really is the famous vessel, but this still needs to be officially confirmed.
History of the Santísima Trinidad
The ship was built in Havana in 1769 and was the largest warship built to date.
Given its large size (length 61.40 m, 52.72 m keel, beam 16.59 m, Depth 8.31 m.;
tonnage 4902 tonnes) the ship was known as El Escorial of the seas (El Escorial
= a historical residence of the king of Spain).
After being tested at sea, they realized that the vessel suffered from several
flaws that were corrected in the shipyards of Ferrol and Cadiz. Such were the changes
implemented that she became the only ship in the world with four bridges. The vessel
ended up with the following dimensions: length 63.36 m., 54.02 m. clean keel, beam
16.67 m, Depth 8.26 m., measured 2475 tons. The crew consisted of approximately
1100 officers and seamen. In July 1779, Spain and France declared war on Great Britain
supporting the American colonies in their War of Independence. The Holy Trinity
was the flagship of the Spanish fleet and took part in operations that occurred
in the Channel in the late summer of that year. In 1780 the ship took part in the
capture of an English convoy consisting of 51 vessels. In 1782 it was sent into
the top corner of the Mediterranean, and participated in the Battle of Cape Spartel.
The ship is remembered for its tragic end at the Battle of Trafalgar (1805).
At that time, the vessel was under the orders of squad leader Baltasar Hidalgo de
Cisneros and Francisco Javier de Uriarte y Borja as Captain of Allegiance. After
a hard and heroic struggle, it was captured by the English in a very poor condition,
with over 200 dead and 100 wounded. The British worked hard to save the ship and
brought her to the British port of Gibraltar, towed by the frigate HMS Phoebe and
HMS Naiades. Eventually, however, she sank about 25 or 28 miles south of Cadiz on
October 24. Symbolising the end of Spanish power on the seas, the greatest war weapon
of its time now remains in the deep sea. The guns were recovered and now lie at
the entrance to the pantheon of distinguished seamen.
Equipment used for wreck detection and imaging
The location of the wreck was done using two KONGSBERG systems by while conducting a demonstration onboard
the hydrographic vessel Malaspina (owned by the Spanish Navy).
The first contacts were established through a KONGSBERG EM 302 multibeam echosounder
that was already onboard. It works with 30 kHz and is specially designed to perform
high resolution seabed mapping with a range from 10 to 7,000 meters. The EM 302
is used for geological mapping from coastal areas to full oscean depth, and is
a world leading product within this market segment.
One of its most outstanding features is the high resolution of the images provided
due to advanced signal processing and a high number of probes (860 probes per pulse).
This allows you to target both in emission and reception. It works with three axes
stabilized: yaw, pitch and roll. The hydrographic vessel Malaspina is also fitted with a KONGSBERG
EA 600 SingleBeam Echosounder (12kHz) and a KONGSBERG Seapath
200 position, attitude, time & heading sensor. Together with its twin Tofiño, services have been performed in most
Spanish waters with high performance. It provides sharp and well defined images
for locating objects such as cables, wires, etc. that have never before been mapped.
Starting out with the bathymetry data, the project team proceeded the inspection
with a dual frequency side scan sonar from Geoacoustics. The
sharp images obtained left no doubt: it was an historic sailing vessel in which
the bridge was fully differentiated. Since the system is available for connection
to a DGPS receiver, we already had the pictures and position of the wreck. The rest
is for the historians to decide.
Sonars of this type are ideal for seabed mapping. Its use is spreading increasingly,
among private companies and official institutions since it is easy to use and has
numerous applications, including civil works, search and rescue, inspection, marine
research and archaeology.