Roberto beat me to Jean Redpath's version. Still, I think her notes are worth adding:

[1987:] Stories of the seal-folk are legion - Ireland, the Outer Hebrides, Argyll, Orkney, Shetland, Caithness, Sutherland, Northeast Scotland and even Norway and Greenland share the tradition of the silkie, or selchie (prob. from Norse selch: seal). Thomas in 1852 described this as "the superstition of the seals or selkies being able to throw off their waterproof jackets and assume the more graceful proportions of the genus Homo". The ballad in this form was recovered in 1938 by Professor Otto Andersson of Finland from John Sinclair of Flotta in the Orkney Islands. Sule Skerry [Sula Sgeir] is a rocky islet 25 miles west of Hoy Head in Orkney. Professor Bertrand H. Bronson (University of California/Berkeley) has a note and further references.
In singing the ballad, the repetition of the verse beginning "My dear, I'll wed the(e?) wi' a ring" left me a little confused as to who was speaking the second time [...] and why. I assumed that the silkie offered marriage the first time, but couldn't quite decide who proposed and who refused the second time. I resolved the dilemma to my own satisfaction, having read the epic of the "Lady Odivere" which includes a similar encounter. On the silkie's return, his reply to her proposal is:
Doo wad no', whin I wad gudewife;   (You wouldn't when I wanted to
I winno, whin doo'r willan noo,      I won't now that you are willing
Dat day doo tint doo'l never faind; That day you lost you'll never find
He's late, he's ower late tae rue    It's late, too late for regrets)                              (Notes 'Jean Redpath')


And this is Sheena Wellington's version (very close to Jean Redpath's) without the question marks. Any further corrections are welcome:

THE GREAT SILKIE O' SULE SKERRIE
Sheena Wellington, Strong Women, Greentrax CDTRAX 094, 1995. Tune: the one used by John Sinclair

In Norowa' land there lived a maid
Baloo, balee, the maid began
Oh little ken I my bairn's father
Nor yet the land whaur he belang

But it happened on a certain day
When this young maiden lay asleep
That in there cam' a great silkie
And sat him doon at her bed feet

Sayin', Awake, awake, my bonnie maid
Awake, awake as thou do sleep
I'll tell you whaur his faither is
He's sittin' here at thy bed feet

Ah pray come tell tae me your name
And tell me whaur your dwelling be
My name it is guid Heim Mailer
And I earn my livin' oot at sea

For I am a man upon the land
I am a silkie on the sea
And when I'm far frae ony strand
My hame it is in Sule Skerry

A woe-, a woe-, a woefu' fate
A weary fate has been laid on me
That a man should come frae the wast' o' Hoy
Tae the Norowa' land tae hae a bairn wi' me

My dear, I'll wed ye wi' a ring
Wi' a ring, cried he, I'll wed wi' thee
Thou may go wed wi' whom thou will
For I'm sure you'll never wed wi' me

Then ye shall nurse my bonnie son
For seeven years upon your knee
And at the end o' seeven lang years
I'll come and pay the nourris fee

And she has nursed his bonnie son
For seeven years upon her knee
And at the end o' seeven years
He's come back wi' gowd and white money

My dear, I'll wed ye wi' a ring
Wi' a ring, cried she, I'll wed wi' thee
Thou micht go wed wi' whom thou will
For I'm sure you'll never wed wi' me

And I'll put a gowd chain roond his neck
An' a gey guid gowd chain it'll be
And if e'er he comes tae the Norowa' land
You micht tak' a guid guess it is he

An' ye shall mairry a gunner guid
And a richt guid gunner he will be
An' he's gane oot on a May mornin'
An' shot the son and the great silkie

A woe-, a woe-, a woefu' fate
A woefu' fate has been laid on me
And sighin' sair she drapped tae the strand
And her tender hairt it brak'd in three

[1995:] Stories and songs of the silkies or seal-people and their dealings with humankind are found widely in both Norse and Celtic tradition but Francis James Child's 'English and Scottish Popular Ballads' has only one fairly short version of this ballad and, of course, no melody. This stark tune and the fuller story were recorded in the thirties from John Sinclair of Flotta in the Orkney Islands. In some versions it is the Silkie who offers marriage the second time but while collating my text from various sources I decided that it was likely that the woman would see marriage as the only way to keep her child. (Notes Sheena Wellington, 'Strong Women')


Dave Burland (Roberto's n-2 above) does not use the James Waters tune, but the John Sinclair one, though with a slightly 'funky' beat, at least on my copy of 'Willin'' (1989).