I got interested in that shallop and here's what I've come up with. It may be a reach, but I rather like it:
171.26 frail shallop By the 19th century, an unusual* word, denoting a small boat for shallow waters. Tennyson’s Lady of Shallott floats to Camelot “unhailed / The shallop flitteth silken-sail’d / Skimming down to Camelot” (21-23).*I would love to use "rare" but that is a term of art for lexicographers, so I'll stay safe with unusual, which I believe to be accurate. The OED's 19th c attestations are to Tennyson and William Holman Hunt: both deliberately archaizing writers.