Lines on ram-air kites shrink after time. When the kite begins to loose its flight efficiency the line lengths must be corrected. This can be done in three(3) ways which are; 1. Buy a new line set, 2. Stretch the lines back to factory or 3. Add larks head extensions to the lines to restore the length to factory settings.
Light and Frost(L&F) prefer to add larks head extensions to restore the line length. This is because if you stretch the lines they just shorten again while larkshead extensions provide a more lasting repair as there is a limit to how far the lines can shrink. Once done kites rarely require another adjustment.
To correct these lines a lineplan from the manufacturer is required. Then using the lineplan a line audit must be performed and larkshead extensions added as required.
Attached is the lineplan from the makers of the Matrixx II for ALL kite sizes in this model. L&F was asked to assist in the restoration of a 15 meter kite size. To keep track of the corrections L&F has written an XLS spreadsheet which calculates the length of line to cut. Generally this is twice the length required for the adjustment plus 7cm for the knot. The spreadsheet can easily be changed to other kite sizes seen on the lineplan. Just unprotect the XLS file and change the factory lengths.
L&F use 100lb test Dacron fishing line when making larkshead extensions. Suggest you use a cloth tape measure used for sewing not a metal one due to the flexibility of the cloth.
We have done many many line audits. Generally when the trailing edge lines connected directly to the kite shrink approximately 10cm it is time to do the line audit. Normally the most shrinkage is also found on these trailing edge lines.