The “Tenlo Chico Lighthouse” tower was built in February 1922 on the small Tenlo Chico peninsula to the south of Tambo Island, at the head of the Pontevedra estuary.
A direct consequence of the Royal Order for the General Coast Marking Plan of the Marin Estuary issued in July 1916, which specified the signals that were to mark the approach channel to the ports of Pontevedra and Marin, its lights first shone out on the eve of 30th November 1922, providing an evenly-sequenced flashing white light that could be seen from a distance of no less than 15 nautical miles from its lofty tower looming 38 metres above sea level.
The initial project drafted by engineer Joaquin Gonzalez Diaz in 1918 was subsequently reformed and taken over by the outstanding road engineer Ramiro Pascual y Lorenzo, head of the Department of Public Works in Pontevedra and the driving force behind the installation of navigation signals in the province over the following decades. The reinforced concrete structure decorated with ashlar masonry has the curious shape of a stub-ended cone tower with an outdoor staircase spiralling around the shaft up to a height of 18 metres.
The tower stands on a massive cylindrical concrete base, also covered with ashlar masonry, where the service room that houses the 12 AK-50 accumulators containing the pressurised acetylene gas dissolved in acetone that fed the Dalen wick that provided the light in the helical crib lantern.
This Tenlo Chico lighthouse was to operate in alignment with another one of identical characteristics located below Cabezo do Medio at Festiñanzo Cape, thus marking an approach channel that guaranteed a safe course to avoid the perilous outcrop that runs south from the Isle of Onza through the Menguella and Pan de Centeno troughs. The lighthouse tower, identical to Tenlo Chico, located in Cabezo do Medio disappeared after being destroyed by waves in a furious storm in the late nineteen thirties.
Nowadays, the Tenlo Chico lighthouse uses solar power to feed its high-intensity white LEDs that trigger 3 white flashes every 9 seconds, with a nominal range of 11 nautical miles.