I can definitely see the boat interpretation. I think though that he's be telling the story of his survival of the shipwreck to his girl here.
"Rambling, where to begin?"
He doesn't know how to start telling his story.
"I tasted summer on your peppery skin"
He's talking to his girl (who has a good amount of freckles, and he's referencing the brevity of time(see chorus)).
"Been saved, the warm of the waves"
He's telling her that he was rescued from the sea.
"I felt a slip into a watery grave"
Just as he was begining to slip away.
"My girl, linen and curls"
He's making sure he has the attention of his girl, then begins telling his tale.
Linen sails (I saw someone was unsure of linen sails so... bruzelius.info/Nautica/Rigging/Sails/Linen-sails.html )
A curl can be used as a term for rope.
"Lips parting like a flag all unfurled"
Lips is indeed a Greek god, and his abandonment is like that of a flag unfurled.
"She’s grand, the bend of her hand"
A grand ship. Hand=Bow?
"Digging deep into the sweep of the sand"
Bow(?) hitting the sand.
"Waylaid, the din of the day
Boats bobbing in the blue of the bay"
They're in the harbor at a busy time of a beautiful day and are being waylaid by something. Perhaps the conversation or the beauty of the bay?
"In deep, far beneath
All the dead sailors slowly slipping to sleep"
And, of course, all of his unlucky shipmates that didn't make it.
"And summer arrives with a length of light
And summer blows away and quietly gets swallowed by a wave"
Summer always seems to pass much more quickly than it should. Here he's realized the brevity of time and how quickly things can be stolen right from under your nose. Life; he almost drowned from a shipwreck.
Love; he can already taste the summer on his girl's skin. He simply hoping that the love he has won't disappear like his life almost did.
I can definitely see the boat interpretation. I think though that he's be telling the story of his survival of the shipwreck to his girl here.
"Rambling, where to begin?" He doesn't know how to start telling his story.
"I tasted summer on your peppery skin" He's talking to his girl (who has a good amount of freckles, and he's referencing the brevity of time(see chorus)).
"Been saved, the warm of the waves" He's telling her that he was rescued from the sea.
"I felt a slip into a watery grave" Just as he was begining to slip away.
"My girl, linen and curls" He's making sure he has the attention of his girl, then begins telling his tale. Linen sails (I saw someone was unsure of linen sails so... bruzelius.info/Nautica/Rigging/Sails/Linen-sails.html ) A curl can be used as a term for rope.
"Lips parting like a flag all unfurled" Lips is indeed a Greek god, and his abandonment is like that of a flag unfurled.
"She’s grand, the bend of her hand" A grand ship. Hand=Bow?
"Digging deep into the sweep of the sand" Bow(?) hitting the sand.
"Waylaid, the din of the day Boats bobbing in the blue of the bay" They're in the harbor at a busy time of a beautiful day and are being waylaid by something. Perhaps the conversation or the beauty of the bay?
"In deep, far beneath All the dead sailors slowly slipping to sleep" And, of course, all of his unlucky shipmates that didn't make it.
"And summer arrives with a length of light And summer blows away and quietly gets swallowed by a wave" Summer always seems to pass much more quickly than it should. Here he's realized the brevity of time and how quickly things can be stolen right from under your nose. Life; he almost drowned from a shipwreck. Love; he can already taste the summer on his girl's skin. He simply hoping that the love he has won't disappear like his life almost did.