Martin 242 Line Lengths

 Some common metric conversions for line diameters: 1/8" ~ 3mm; 3/16" ~ 5mm; 1/4" ~ 6mm; 3/8" ~ 9 or 10 mm; 1/2" ~ 12 or 13mm

• Spinnaker Halyard: 1/4" x 75 ft.
• Reef: 1/4" x 25 ft.
• Pole Down: 1/4" x 30 ft.
• Pole Up: 1/4" x 45 ft.
• Vang: 1/4" x 22 ft.
• Backstay purchase: 1/4" x 17 ft. N.B. This is the purchase line between blocks, not the actual backstay.
• Backstay line or wire: distance from mast crane to top centre of pushpit is 34’4”. Wire backstay length should be 33’6”, plus 3” either end for crimping length, plus another 2'-3' depending on the length of backstay whip. Rope backstay length can be 33’ or 33’6” plus 6” either end for tying knots plus 2'-3' depending on length of backstay whip, plus another 2' if splicing is being done at each end rather than tying bowlines or similar. Rope can be 3/16” or 1/4” Amsteel, Dyneema (better), or similar.
• Traveller: 1/4" x 22 ft. for 2:1 Purchase; 32 ft for 3:1 system NOTE this assumes one line end to ended; not 2 pieces.
• Cunningham: 1/4" x 18 ft.
• Cunningham strap: 1/4" x 5 ft.
• Spinnaker Sheets: 2 @ 5/16" x 60 ft. (8 mm x 18.3 M) tapered for the last 12 feet
• Jib Sheets:
  • 1:1 system 1 @ 3/8" x 45 ft. 
  • 2:1 system 2 @ 5/16" x 30 ft. (7-8mm) tapered for the last 30" (762mm) down to a 6mm Dyneema core with a braided loop at the end to attach a Wichard clip. (3/8" is too thick for the taper point to pass easily through the bullet blocks on the jib)
• Jib Halyard: 3/16" x 27 ft.
• Jib Messenger (Halyard tracer) line: 1/8" x 27ft
• Main Sheet: 3/8" x 65 ft.
• Main Halyard: 3/8" x 78 ft.
• Furling Line (small harken drum): 3/16" x 25 ft. (the first 10' to coil into the drum may be tapered)
• Furling Line (large Harken drum): 1/4" x 25 ft. (again the 10 ' of line coiling into the drum can be tapered)

Diagram for Harken deck hardware, blocks, & lines: