Running Rigging: What Type of Rope to Use for Cruiser Racing & Where to Get It?
SK38 Popular for cruising boats where the stretch of Polyester is not acceptable but where they are not prepared to go with the pricing levels of SK 78 or SK 99. SK 99 Really top of the line low stretch. This would be the rope of choice for large high-end race boats. It would be approximately. 40% stronger than SK78 and used for a boats ultra-strength bearing needs such as Code 0 halyards, Tack lines and perhaps even headsail halyards. On average, it would be about 70% more expensive than SK78....
Source: afloat.ie