I have been experimenting a bit with tying ratlines. Assume working from left to right.
The first clove hitch round the left hand shroud poses no problem.
On the second and subsequent shrouds it is difficult to keep the section of ratline sufficiently taut to
make the section from the previous shroud straight (without displacing it) and simultaneously tightning the clove hitch.
Once a clove hitch is tight it can be slid up and down the shroud but its position along the ratline is immutable.
(I wonder if anyone has ever been brave enough to tie clove hitches with the shroud around straight ratlines?)
The following helps a bit.
When the clove hitch is formed but not quite tight insert a needle between the two half hitches.
Pushing the needle to the left while holding the free end of the ratline pulls the two half hitches against the shroud.
Pulling on the free end while offering some resistance with the needle will tighten the knot while maintaining the desired point of
contact between the current shroud and the section of ratline from the previous shroud.
Essentially the needle keeps the first half hitch tight while the second half fitch pulls the needle to the shroud.
Finally, close the knot by removing the needle while simultaneously pulling the free end of the ratline.
With a fine needle the riny length of released line will not significantly affect the desired position of the completed knot
with luck it will be absorbed via the half hitch next into the free end.
The images below try to illustrate the principle using some more visible thick cord. The red bit is the ratline from the prvious shroud.
The free end is the exit line from the upper half hitch. The dowel represents the needle.
A similar technique could be used with a simpler, quicker (but less elegant) overhand knot.
I also experimented with a cow hitch but that achieves nothing.
Is there anybody out there who actually enjoys tying ratlines?