Well, I translated it for you, LandsLad - which I think is what you wanted - but bits of it didn't make much sense so I took it to my Welsh learners' singing group last night and checked it out with the Welsh tutor and a couple of native speakers. They agreed. (Saying farewell to Wales while standing in Ireland?) Anyway, sometimes it just doesn't pay to think too deeply about these things and it's a cracking good song so who cares?

Daeth diwrnod i ffarwelio
Ag annwyl wlad y Cyrmo
Gan sefyll ar hen dir y Werddon Fras;
Fe gododd gwynt yn nerthol
Y môr â'i donnau rhuthrol,
Gan olchi dros ein llestr annwyl las.

Dewch, Gymry glan, i wrando ar fy nghân
Fel bu y fordaith rownd yr Horn - rownd yr Horn!
Sef y trydydd dydd o'r wythnos
Ychydig cyn y cyfnos
Gan basio ger glân greigiau glannau Môn.

Rwy wedi mynd a dwad
Mewn llongau hardd eu gwelad
Ond dyma'r wyrcws benna gefais i,
Does yma ddim i'w fwyta
Ond gwaith sydd lond ein breichiau;
O, galon, pwy all beidio bod yn brudd?

So, roughly,

The day came to say farewell
To the dear land of the Welshman
Standing on the fertile Irish land **;
A wind heaved up
The sea and its rushing waves,
So washing across our blessed dear ship.

Come, good Welshmen, to listen to our song
Of our sea journey Around the Horn! Around the Horn!
That is, the third day of the week,
Just before dusk,
Passing near Anglesey’s fair rocky shores.

I’ve come and I’ve gone
In ships beautiful to see
But this is the worst workhouse I’ve ever experienced;
There’s nothing to eat
But there’s an armful of work;
O, my heart, who could but be downhearted?

I think maybe Ar Log recorded it on an album once as well, but I can't think which one off hand.

siân