The late Maggie Boyle was the vocalist on this John Renbourn recording;

https://www.youtube.com/watch?v=GWjDUEsD6lU

Maggie posted the lyrics above, but in pieces. Let me see if I can put all the pieces together. She says that Steve Tilston and John Renbourn wrote most of the song, but Tony Roberts and Maggie Boyle were also given songwriting credit.

SHIP OF FOOLS
(Renbourn/Tilston/Boyle/Roberts)

The sun shone on the morning
When first I saw the ocean-o,
It sparkled like a looking-glass.
At bay its mighty motion-o
The tall ships lined along the quay
A breeze danced through the rigging-o.
But one ship chanced to catch my eye,
And I heard the sweetest singing-o.

A stranger craft I'd ne'er beheld
In picture book or fancy-o
Rainbow colours that befell
From stem to stern entranced me-o
The sweetest voices drew me on
I lacked the will to tarry-o
Charmed aboard the ship of fools
Away the wind did carry-o

I called out for the captain
Enquiring of our journey-o
And there beheld a lady fair
She set my heart a-yearning-o
"I am your captain, sir" she said,
"I go where no man dares to go
And you will serve me up aloft
And likewise serve me there below

Upon my hand she placed a ring
With rarest jewels so-fine o
"This token sir" she said to me
"'T'will bind your heart to mine-o
This ring shall keep you ever young,
Safe from the toll of time-o
And keep you on the ship of fools,
Long as the stars do shine-o"

She took me to her cabin and
She kept me to the matin-o
I searched to find my sea legs bold
Between the sheets of satin-o
Aloft upon the empty deck
No seamen could I find-o
But cold waves lapped our lonely bows
And seabirds flew behind-o

We ploughed the foam (waves? seas?) and sighted land
But never touched the shore-o
And we did roam for seven years
'til I did yearn no more-o
In captive arms I was entwined
Reluctant to release me-o
The ship of fools bids no adieus
Until the last wave ceases-o
The ship of fools bids no adieus
Until the last wave ceases-o