Reference for Shabbat 15:1
אֵלּוּ קְשָׁרִים שֶׁחַיָּבִין עֲלֵיהֶן, קֶשֶׁר הַגַּמָּלִין וְקֶשֶׁר הַסַּפָּנִין. וּכְשֵׁם שֶׁהוּא חַיָּב עַל קִשּׁוּרָן כָּךְ הוּא חַיָּב עַל הֶתֵּרָן. רַבִּי מֵאִיר אוֹמֵר, כָּל קֶשֶׁר שֶׁהוּא יָכוֹל לְהַתִּירוֹ בְאַחַת מִיָּדָיו, אֵין חַיָּבִין עָלָיו:
These are the knots that one is liable for: the knot of the camel drivers and the knot of the mariners. [The camel drivers bore a hole in the camel's nose, place a thong there and tie it with a permanent knot. Likewise, a hole is bored in the bow of the boat, and a rope placed there and tied with a permanent knot which is never untied — comparable to the knots of the curtain threads which became undone in the tabernacle. For a permanent knot which is not the work of a craftsman, or for the work of a craftsman which is not a permanent knot, one is exempt, but it is forbidden. One is not liable until it be both permanent and the work of a craftsman. And if it is neither, it is permitted ab initio.] And just as one is liable for tying it, so is he liable for untying it. [For the chilazon trappers had to untie their net knots in order to shorten or broaden the nets.] R. Meir says: Any knot that [was not tightened so that] one can untie it with one of his hands, he is not liable for, [even if he intended it to be permanent. The halachah is not in accordance with R. Meir.]