[Grammar] a sloop-rigged sailboat whose three sheets have slipped through the blocks are lost

[kadioguy]

sheet (n.2)

"rope that controls a sail," late 13c., shortened from Old English sceatline "sheet-line," from sceata "lower part of sail," originally "piece of cloth," from same root as sheet (n.1). Compare Old Norse skaut, Dutch schoot, German Schote"rope fastened to a sail."

This probably is the notion in phrase three sheets to the wind "drunk and disorganized," first recorded 1812 (in form three sheets in the wind), an image of a sloop-rigged sailboat whose three sheets have slipped through the blocks are lost to the wind, thus "out of control." Apparently there was an early 19c. informal drunkenness scale in use among sailors and involving one, two, and three sheets, three signifying the highest degree of inebriation; there is a two sheets in the wind from 1813.

https://www.etymonline.com/search?q=sheet
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1. Is the blue part grammatical? It has two verb parts (have slipped and are lost), so I think 'no'.

2. Should it be '... a sloop-rigged sailboat whose three sheets that have slipped through the blocks are lost to the wind ...'?

What do you think?

 

[GoesStation]

It should say whose three sheets have slipped through the blocks and are lost to the wind.

 

[Charlie Bernstein]

And here's some unsolicited trivia: The only ropes on a sailboat that are called ropes are the ones used to tie the boat to a dock.