Control Line Recommendations
|Dinghy / Small Boat Recreational
4mm / 5mm Robline Sirius 500
|Dinghy / Small Boat Performance
2mm / 3mm / 4mm / 5mm Robline Dinghy Control
4mm / 5mm Marlow Excel Racing
|Keelboat / Cruising Recreational
6mm Marlow DoubleBraid
|Keelboat / Cruising Performance
6mm Robline Dinghy Control Line
Finding The Right Diameter
If you are replacing an existing line, the easiest way to determine what diameter you need is to match what you already have. This can be done with a caliper or by close estimation with a tape measure. If you've previously used a 5mm control line and it has performed well, another 5mm line is likely a great choice. In most applications, there is some flexibility in the exact diameter that can be used. Most blocks, for example, have an 'ideal' diameter (ie, the line diameter that runs most effectively though the block's sheave) but also have a range so that you can run a slightly thinner or slightly thicker line. If you have a control line that is getting hung up in your rig, stepping down 1-2mm might help the halyard run more efficiently. If you have a larger boat or rig and want to run a thinner control line , consider a double braid high tech line that features a Dyneema or spectra core for strength.
Line Diameter Conversion
1mm = 3/64 inch | 2mm = 5/64 inch | 3mm = 1/8 inch
4mm = 5/32 inch | 5mm = 3/16 inch | 6mm = 1/4 inch
7mm = 9/32 inch | 8mm = 5/16 inch | 9mm = 3/8 inch
10mm = 25/64 in | 11mm = 7/16 in | 12mm = 1/2 in
Double Braid vs Single Braid
Two terms you will often see in line descriptions are 'double braid' and 'single braid', which refer to the way the line is constructed. At the most basic level, a double braid line has a cover and a core whereas a single braid does not, but there are other important distinctions to consider when making a line selection.
Single Braids are made up of either 8 or 12 strands that are braided into a circular pattern, half clockwise and half counter clockwise. This produces a line that is supple, absorbs twists, and tends not to kink. There are two types of single braid lines: performance single braids and polyester/blended single braids. Performance single braids are made from fibers with very low stretch and designed to handle extreme loads - think Dyneema, Spectra, or Vectran. Polyester/blended single braids, sometimes called hollow braid, are soft and easy to grip, built for sheets and hand-adjusted control lines. These are less common than performance single braid lines but recommended in a few specific applications.
Double Braids, sometimes called braid on braid, have a braided core within a braided outer jacket or cover. This creates a strong, durable, smooth-running line that is easy to handle. Double braids are used for the vast majority of all running rigging on sailboats including sheets, halyards and control lines for both cruising or racing. There are two types to consider: polyester double braids and high-tech double braids. Polyester double braids, found most commonly on recreational and cruising sailboats, have a polyester cover with polyester core. These are low maintenance, affordable, and long-lasting, while offering relatively low stretch and high working loads. For additional strength and minimal stretch, consider high-tech double braids. These lines typically feature a Dyneema or Spectra core (non-stretch) inside a polyester or polyester/dyneema blend cover for additional durability. They are more expensive but often the go to choice for high performance racing boats.
For control lines, we typically recommend Double Braids, particularly for the portion which is either cleated or is handled by the sailor. If you control line system requires a 'secondary' line (such as on a Laser vang, for example), a single braid high tech line such as Dyneema or Spectra is appropriate.
Whipping & Splicing
Looking to clean up the end of your line or need to add a splice to your rig? Visit our Whipping & Splicing page for a full selection of whipping twine, fids, splicing needles, and complete splicing kits. Perfect for the DIY sailor looking to further optimize their rigging.