Seine Twine #42 Black Tarred Nylon
Hard to find.
Used below salt water line on fishing boats.
#42 is our middle weight.
Best used for lashing open boats were there is much abrasion and abuse.
#42 Major connection joints examples knees to stems or gunwales to breast hooks.
Also excellent for outdoor construction and structures.
1 lb rolls.  
Made in Washington State, USA  app 475' per roll