A main halyard should have a low elongation. This is required for properly trimming your sail: when the wind increases, you want your main sail to stay flat. For Dinghy regatta we recommend the ropes below.
Suggested length, here Suggested diameter, click here
This top quality high performance regatta rope, has a core made of coated Dyneema® SK78 fibers and 24 braid HT Polyester cover. Features: Suitable for splicing and tapering, very low stretch, light weight, great durability. Excellent for halyards.