The Rambam understands the idea of Ptil as the string which winds around the others. Therefore, he requires all the twists to be of Tekhelet, except for the very first and very last. He defines a chulyah as a group of three twists. In this method, the chulyah is kept together by wrapping the string inside the chulyah. Though the Rambam doesn’t explicitly say so, generally a double knot is tied at the base where the strings touch the begged.
Note: Rambam 7 is exactly the same, but with 7 chulyot instead of 13.
Hilchot Tzitzit, Ch 1
7) One of the white threads is taken up and wound once about the other threads close to the garment. It is then dropped. The blue thread is then taken and wound twice about the other threads close to the winding with the white thread. The threads are then tied. These three windings are called a section. A small space is left; a second section is made, the windings being done with the blue thread only. A small space is left; a third section is made; and so till the last division where the blue thread is wound round the other threads twice and the third winding is done with a white thread, because, as the winding began with a white thread, it should also end with a white thread, on the principle that things sacred may be elevated to a higher degree but may not be degraded to a lower degree. The reason why the winding begins with a white thread is that the corner of the garment shall have adjacent to it threads of the same kind of material. This is the method followed with the four corners.
8) How many divisions are made in the fringes at each corner? Not less than seven and not more than thirteen. This is the choicest mode of carrying out the precept. But if one wound the threads, to form one division only, the fringe is regarded as correctly made. And if one wound the blue thread over the greater portion of the fringes, it is correctly made. The beauty of the blue thread is manifested if all the sections that are wound take up the first third of the pendent fringes, while the remaining two thirds are loose. The threads in this part need to be separated, so that they shall be like the fringes of hair on the head.
The initial “Chulya” is made by wrapping one white strand and one blue strand and tucking in the ends to form a knot. The white is wrapped once first and then the blue twice.
The 11 middle “Chulyot” are made by taking one blue strand from the total of eight strands and wrapping it around the remaining seven strands three times, and tucking the end into the wraps to form a knot. This “wrapping” strand is designated “Shamash” and is used for all subsequent chulyot (though it is not halachically imperative that the same Shamash be used).
The final “Chulya” is made by wrapping one white strand and one blue strand and tucking in the ends to form a knot. The blue is wrapped twice first and then the white once.
Rav Kapach holds Rambam tying should NOT have the double knot on top. It's in deference to the Ran that, bedieved the mitzvah is fulfilled by the first double knot. (R'
David Ely Grundland).
From Ptil Tekhelet:
2 Rambam setsH/T Dovid Aronin
Rambam with Raavad strings
Rambam with no Kesher ElyonRav Kapach holds Rambam tying should NOT have the double knot on top. It's in deference to the Ran that, bedieved the mitzvah is fulfilled by the first double knot. (R' David Ely Grundland).
