No, sail ties, are not novelty men's wear!
If you have a sailboat, you are going to need sail ties. Sometimes sail ties refer to strings or ropes that actually tie the mainsail to the boom, but in this post I am talking about sail ties that are used to secure a sail when it is not in use. They tie a lowered mainsail to the boom or can be simply tied around a loose jib to keep it from flapping or being blow overboard. Some sailors tie the jib to the lifeline or fore stay for extra security.
A second common use for sail ties is to secure the mainsail when reefing. When the wind picks up you need less sail area. Reefing consists of lowering the mainsail partway. Sails built for reefing will have cringles (grommets) at one or more reefing points. You usually have a line already attached to the cringle nearest the mast that is used to pull the sail down but may need to thread sail ties through other cringles along the sail to secure it to the boom so it isn't flapping in the breeze or hanging down blocking your view or getting in your way. Some reefing ties are permanently attached to the sail so they are always there when you need them.
There are several options for what you can use for sail ties. Some guys like to use bungee cords. Some just use pieces of rope. But one of the easiest I've used are nylon straps. They have a loop sewn in one end so you can get a good hold on them to yank them tight. The loop is usually sewn with a twist in the strap so it is easier to open to get your hand into it. Bungee cords elasticity makes them useful in that they can be stretched around different parts of the sail. The only downside might be the hook chafing on the sail or gouging your hand if they slip while you are trying to fasten or unfasten them.
In the photo note the box stitch used to form the loops and that the loops are twisted so they are easier to open when you use them. Nylons straps are not usually used for reefing as they don't fit as well through the cringles as a light weight rope but you might use them in a pinch by folding or rolling them lengthwise to fit them through the cringle. If you do a lot of reefing you are going to want dedicated reefing ties to make the job easier.
How many sail ties do you need? I suggest using at least 1 sail tie every 2 feet. On a mainsail with a 10' base or foot that would be about 6 sail ties, one at each end and one every 2' in between-- at 0, 2,4,6, 8, and 10 feet. I use about the same number on my jib, which also has about a 10' base or foot. The number of ties you need for reefing will depend upon the number of cringles in your sail. If you have multiple reefing points (at different levels on the sail) you might want to have a set of reefing ties for each reefing point. The ties needed for more than one reefing point will need to be successively longer for each level since there will be more sail to be tied off. You might get away with having just one set but it would mean untying and retying previous reefs each time you reef again. I like the idea of keeping the previous reefs tied off so I don't risk losing control of the already reefed portion of sail while retying more reefs
How to tie a sail tie. There isn't really any wrong way to tie sail ties as long as they hold in place and do their job. However, there are some techniques that work better than others. You want them to hold securely yet be easy to undo when you are ready to use the sail again. I like to use long ties so I can take a couple of loops around the sail to spread the load. Then I pull the tail (end opposite the loop) and pull the end of tail through the loop so I can cinch it down tight, then tie off the loose end. When I tie off the loose end I use another loop to form about a half a bow knot so I can get the whole thing loose by just pulling on the loose end. P pull one loop under the tie next to the sail and then pull antoher loop through that loop. That way I only need pull the loose end when it is time to undo the tie. Sometimes time is critical and you will want to be able to get the sail back in service quickly. Try avoid making small, tight knots as it they will difficult to untie and repeated use can weaken the strap. You definitely don't want to tie knots so tight you have to cut them to get them off!
Don't leave sail ties on the jib when you stow it away. Open it up and flake it right so it lays flat. You can leave sail ties around the mainsail when it is left stowed m the boom in a sail cover.
Where to get sail ties? You can buy sail ties at any marine supply store that caters to sailboats and online, including amazon.com. They usually come in sets of 4 or 6. You can usually choose a color to match your sail covers or coordinate with other colors on your boat. I like to have a variety of lengths since I only need short ties near the clew of the sail and longer ones as I work up toward the mast and the amount of fabric increases. Nylon strap ties can be easily cut to length. If you don't have an electric hot knife to cut them you can use a lighter to melt the frizzy end to keep it from unraveling. You might even find other uses for the cutoff ends.
You can make your own sail ties too. You can purchase nylon strap on-line or at many fabric stores. Figure out how many ties you need of each length and add a foot extra for each tie. The extra foot will be used to sew the loop. When forming the loop, put a single twist in the strap instead of just laying it over on itself. That will make opening the loop easier when you need to use it. Use a box stitch about 1" long to fasten the end back on the strap using about 1' of strap to form a loop about 6" long. Be sure to use thread that is designed for outdoor use and sun exposure. Match the color of the thread to the color of each strap for the most professional looking results. If you have multiple colored straps and want to wave a couple of bucks, you might sew them all with the same neutral color. Dark thread on light straps or light thread on dark straps will be the most noticeable but with the small amount of stitching it probably won't make much difference. All the ties in the sample photo above used white thread. You can find instructions along with kits for making sail ties at Sailrite.com.
I can custom make sail ties for you for $.40 per foot plus shipping. Add 1' to your desired finished length for the loop. Choose Pacific blue, red, green, yellow, or black. Email your requirements (# of ties and lengths) to email@example.com. I prefer Paypal. I will also accept personal checks, but it may delay your order while I wait for your check to arrive and clear. Include your shipping address. Upon receipt of your email order I will reply with a total including shipping and an estimated shipping date.
You might want to have bunch of sail ties all the same color to coordinate with colors on your boat, but it is sometimes useful to have different colored sail ties of different lengths to make it easier to find the length you want for each position on the sail.
Sail ties should be stored where they don't get tangled are are easily accessible when you need them. I rigged a hook on the magazine rack just inside the companionway hatch on my sailboat. They hang straight down, are generally out of the way, and yet I can easily grab them when I need to secure my sails.
Tie one on!