The blog at the link above is not about a shanty group, it's about a trip with a copy of Colombus' ship La Santa María. I browsed all the articles and there's no mention of any Spanish shanty. In Spanish you can find El marinero borracho which is a Spanish version of "The Drunken Sailor" and this one but if you read the lyrics, they mention Microsoft, Harry Potter, The Lord of the Rings -no comment!
On this page there are lyrics written in 2017 and no sheet music.
If you read the 28-09-2009, 08:52 post on this link, it reads "…from Spain, you can't find anything." "…but nothing of shanties i.e. work songs, but of after work.", "…in Spanish I don't find anything."