
PLS-CADD is the product they use. Hope it helps.
http://www.powline.com/products/pls_cadd.html
How about catenary calculations for your boat anchor using MS Excel?
http://www.johnsboatstuff.com/Articles/anchor.htm
or Catenary for dummies at http://www.offshoremoorings.org/moorings/2005/catenaryb/CCCP_manual.pdf
Antenna wire catenary calculator at http://vk1od.net/calc/awcc/awcc.htm