By knitting half-tubular, you can create single jersey knitting that is twice as wide as the machine, which can be useful for garments such as skirts or dresses.
In a regular tubular, you alternate rows of single jersey on the front and rear beds. Half-tubular is created the same way, except you alternate the rows of front and rear bed knitting in pairs.
Racking the needle bed is unnecessary when knitting tubular because the needles, although opposite of each other, are never in use at the same time. This means there is no risk of colliding needles.
Select the line drawing tool and draw pairs of rows of alternating front bed and rear bed single jersey.
Below is a detail of half tubular knitting.