When buying Sailing Boat Ropes, you must take into consideration a few aspects. The length is the most important. This length is ideal for boats that are less than 20 feet long. However, if you want to save money, you could select a rope that is more extensive. Next, decide what type of cover you need. Make sure the ropes have a central core. Double-braided ropes come with an inner core and a cover however single-braided ropes don't have the core.