The Maltese-flagged Althini II arrived in Las Palmas, Gran Canaria, from Lagos - a journey of more than 2,700 nautical miles - according to data collected by maritime tracking websites.
Three Nigerian men, on Monday, were found in the rudder of a ship which sailed for 11 days from Nigeria to the Canary Islands.
According to EFE, a Spanish news agency, the men were seen by medics at the dock and were taken to hospital at the tanker's destination in Gran Canaria and treated for dehydration and hypothermia.
Two of the three men have been discharged from the hospital but the third is still hospitalised although stable.
It remains unclear if they spent the entire journey perched on the rudder.
Txema Santana, migration adviser to the Canary Island, in a tweet said the ship went from Nigeria to the Canary Islands without a stopover.
The official said the survivors said there are only three of them left, indicating that there may be more than three who embarked on the journey.
"... after a few days they ran out of food. So far it is unknown if they have had access to request international protection," Mr Santana said.
The Maltese-flagged Althini II arrived in Las Palmas, Gran Canaria, from Lagos - a journey of more than 2,700 nautical miles - according to data collected by maritime tracking websites.
Recent history of such travels
BBC reckons this is not the first time stowaways have been found on rudders, which are large blade-like fins found under ships and used for steering.
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In 2020, a 14 year-old boy travelled from Lagos to Gran Canaria in 2020 spending 15 days on the rudder of a huge fuel tanker.
He was hospitalised upon arrival. In his interview with El Pais, he said he survived on salt water and taking turns sleeping in a hole above the rudder with the other men he was travelling with.
In the same year, four men were found on the rudder of the Norwegian oil tanker, Champion Pula, after it had travelled from Lagos to Las Palmas. Reports at the time said the men hid in a room behind the rudder during its 10 days at sea.
The number of migrants crossing on boats from West Africa to the Spanish-owned Canary Islands has risen significantly in recent years.
The journeys are long, hazardous and deadly. In 2021, the UN's International Organization for Migration (IOM) recorded 1,126 deaths on the route.
