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Installing Roller Furling

This article was originally published on SailNet in May 2001.

Roller furling systems are as common as lifelines these days—almost every vessel has one or more.
Wrestled any monsters on the foredeck lately? Slippery folds of Dacron that tumble down onto the deck can come to life with each gust of wind as you battle to control a flailing sail that seems to have a mind of its own. You know if you lose this round, it means another wet sail that can't be folded or stowed until it's dry. When you compare this scenario to the ease and joy of being able to quickly furl or reef your headsail from the security of your cockpit, it's easy to understand why roller furling is considered one of the greatest innovations today by sailors worldwide. Whether your boat is 18 feet or 80 feet in length, the addition of roller furling will help you tame that foredeck monster and make your time spent sailing not only safer, but more enjoyable as well.

Though roller-furling units haven't always been fool-proof, modern roller furling systems are better than ever, allowing allow you to easily and reliably reduce or eliminate sail at any time. You simply roll in as much or as little sail as you want. As the wind pipes up, you furl the sail until you've reduced the sail area enough to balance the boat and the helm is no longer overpowered. Later, if the wind goes light, you can unroll the sail and presto—full speed ahead! The task of having to go forward to change from one size headsail to another, or to douse and stow sails, quickly becomes a relic of the past.

Not long ago we installed a roller furling system for the staysail on Serengeti, our 46-foot Formosa Peterson. As we almost always sail shorthanded, we felt this was the perfect complement to the existing furler on our headsail to further minimize our time spent on the foredeck and to make sail handling an easy, one-person job.

By installing it ourselves, we not only saved money, but learned a great deal about what we consider to be one of the more important systems on our boat. The unit we chose is a Schaefer 3100. Like many of the new systems, it's designed for easy owner assembly and installation. Although our particular installation was on a staysail, the procedure is identical for a headsail. We'll show you and describe in detail how the Schaefer 3100 goes together.

The authors opted to add an extension toggle beneath their new unit, which may tend to sacrifice performance from the sail plan but will certainly foster better visibility for traffic ahead and to leeward.
Different furling manufacturers offer their own unique extrusion shapes, methods of connectivity, type of drums, bearings, etc. For example, ProFurl joins their elliptical extrusions together with setscrews, whereas Schaefer connects their round extrusions with stainless steel pop rivets. Conceptually, the installation of similar sized furlers by different manufacturers is pretty much the same and each manufacturer provides detailed instructions. Our installation should give you a good idea of what to expect regardless of the brand you choose. And some of the components for roller furlers designed for smaller boats are engineered to simply snap together. This makes their installation much faster and easier than on larger boats.

Choosing a Unit    To choose and order a roller furler to fit your boat, you'll first need to compile some basic information:

  • What size is your boat?
  • What diameter is your forestay?
  • What is the length of your forestay? (Measure from center of pin to center of pin)
  • What is the diameter of the clevis pin on the stay?

With the above information in hand, you'll be able to follow each manufacturer's guidelines to correctly size your unit. There are also some other features you may want to take into account when shopping. Some manufacturers like Schaefer, Harken, and Hood incorporate a removable split drum into their design. This introduces a new flexibility. For racing enthusiasts, high-tech racing sails can replace a furled cruising sail, and the removal of the drum decreases windage and weight. Some extrusions are manufactured with twin grooves instead of just a single groove. These allow the racer to quickly execute headsail changes while the cruiser may find them useful on long downwind passages for flying double headsails wing-on-wing.

The extrusions on the authors' new unit connect by way of a cast aluminum insert that is riveted in place.
Headsail Concerns    When upgrading to roller furling, you'll need to modify your existing sail or order a new one. If you choose to modify your old sail, your sailmaker will replace its hanks with the appropriate sized luff tape to fit the extrusion, and add a UV cover to the leech and foot of the sail so that the dacron is protected from the sun when the sail is furled. Deterioration of sail shape is always a concern with partially furled sails because of their built in draft. Over the last few years, sailmakers have addressed this problem by adding a "foam luff." Foam sewn into the leading edge of your headsail forces the sail to flatten as it is furled. The result is better sail shape when you sheet in a partially furled sail.

Step by Step Assembly    Get your tools together and review the instructions in advance. Don't forget the bucket to contain all the little parts. If you've prepared in advance, you should be able to do this installation by the end of the day.

Begin by removing your stay and stretching it out on the dock. If your mast is up, someone (in our case Sue) will need to go up in the bosun's chair to remove the top pin. Be sure to have the stay tied to a halyard prior to pulling the pin—a series of clove-hitches works well here. Slowly lower the halyard and stay onto the deck.

Next, it's time to do some measuring. The Schaefer 3100, like several other brands of furlers, requires you to cut the stay, remove the appropriate amount of wire, and re-make the fitting at the upper end with a Sta-Lok terminal. We added a double jawed toggle at the top end along with the Sta-Lok, and a long integral toggle link at the bottom. The double jawed toggle is necessary to allow the stay to fully articulate. The long toggle link raises our drum off the deck, allowing us better visibility under the sail, and provides a fair lead back to the cockpit for the furling line.

"Using a double- jawed toggle at the top is necessary to allow full articulation of the stay."
Determining how much wire to remove is an easy task. Detailed info was provided to guide us through this process. After making your calculation, measure down the stay and cut the wire with wire cutters or a hack saw with a new blade. It must be a clean cut as this is where your Sta-Lok connection will be fitted.

With the stay cut to the correct length, the rest of the installation is quite straightforward. The parts that will now be fed onto your stay can be broken down into several groups. The lower drum assembly, multiple extrusions and joints, an upper swivel and a Sta-Lok fitting. When combined, these components allow the extrusions, drum and upper swivel to turn freely around your existing stay.

Disassemble the lower drum and slide each component over the stay and down to the bottom. Reassemble the inner parts that are required to spin with the joined extrusions. Next, beginning with a special heavy-duty bottom joint, slide each extrusion over and down the wire. Don't forget to place the sail feeder in between the first and second extrusion pieces. The 84-inch extrusions are fastened together by a cast aluminum joint that is inserted between two extrusions and riveted with stainless steel rivets.

A plastic liner rests inside each joint to insulate the joint from your stay. This reduces friction and enhances corrosion protection. Apply Tef-gel to each rivet hole prior to assembly to reduce future corrosion of dissimilar metals. We found that installing stainless steel pop rivets with a normal "hardware store" rivet gun to be quite difficult at first as a lot of strength is needed to pop the rivet. We soon found that by inserting a couple of three-foot lengths of stainless tubing over the ends of the handles, with the added leverage even Sue could easily make that rivet pop.

The last piece of extrusion at the top usually has to be cut to size and we recommend using a hacksaw for this. In the case of our Schaefer unit, this piece had to be no shorter than 18 inches in length to properly accept the special top joint. This sometimes means using a supplied half-length piece of extrusion for the next to last piece of extrusion in order to meet this requirement.

By adding lengths of pipe to the handles of the rivet gun, the authors could exert additional pressure on each rivet.
Once all the extrusions have been solidly riveted together, you're ready to slide the upper swivel over them all and down to the feeder. Ensure that this swivel slides freely over each connection. This upper swivel is what the head of your sail will be connected to and must travel freely to be able to raise and lower the sail. Add the top cap to the top extrusion, align and tighten the setscrews.

Return to the bottom of your furling unit, disassemble the bottom drum and open the turnbuckle as much as possible. This will help with fitting the Sta-Lok and make re-attaching the stay to the boat easier. Reassemble the bottom drum.

The last dockside task prior to hoisting your furler into place is to make your Sta-Lok connector at the top of the stay. With every Sta-Lok unit come detailed instructions for fast and easy assembly, using just a couple of crescent wrenches. These fittings are considered universally to be extremely strong, safe, convenient, and as a bonus are re-usable.

Now you're ready to raise the furler into place. Again, using a halyard, tie a series of clove hitches approximately three feet down from the top of your new furling unit. With dock-mates helping to support the middle and lower section of the furler, slowly raise the unit with the halyard. Special care must be taken not to bend or kink your new full-length extrusion. Make sure the upper swivel is resting at the bottom of the extrusion to avoid having it come sliding down in the raising process. Reconnect the upper and lower clevis pins. Because you opened your turnbuckle as much as possible, your first reaction may be, "Oh no, it's too long." Don't worry though, this slack is taken up quickly as the turnbuckle is tightened. Attach the furling line to the drum and determine your best path back to the cockpit. The straighter the run, the less friction you will encounter.

Once the segments of tubing were connected, Sue slid the headstay into the foil and then added the upper swivel and the drum at the bottom.   
With your furler is in place and sail raised, you'll want to analyze the angle of pull on the upper swivel by the halyard. To avoid halyard wrap and possible damage to your system, this pull must be parallel to or slightly aft of the angle of the headstay. If your angle is less than parallel to the headstay, you'll want to add a halyard restrainer to the mast to pull the halyard lead aft.

Time to hit the water and test out your new system. To ensure smooth furling make sure you always keep light tension on the furling line as the sail goes out. This will make sure that the wraps around the drum are even and uniform, and eliminate what we used to call when it happened to our fishing reels as a "bird's nest." Neglecting to do this could cause your furler to jam. This practice also allows you to easily stop unrolling the sail at any time if a full sail is not needed.

When furling the sail in again, keep light tension on the jib sheets as the sail rolls up to help the sail furl tightly around the stay. Once the sail is completely furled, make several more wraps of the jib sheets around the furled sail and secure the sheets to eliminate the sail getting loose, and possibly tearing, in high winds.

"Whether you plan to cross an ocean or a lake, roller furling is a smart equipment upgrade."
Whether you plan to cross the ocean or cross the lake for a picnic, roller furling is a smart equipment upgrade. You'll enjoy your time spent on the water more knowing you can quickly and effortlessly amend your sail plan for any given condition.

For Sue and me, an extra bonus of having roller-furling sails is that we no longer have to fold sails together. We seem to fail dismally at this task. Since she was a sailing instructor for many years, Sue always insists that I'm doing it wrong. I accuse her of having the boys fold her sails for her years ago and that she never actually learned herself. Now, with two roller-furling headsails, lazy jacks on the mainsail, and a sock for our cruising spinnaker, we're pretty much free of sail folding. Uh-oh! I forgot about our 10-foot sailing dinghy! I'll set her straight eventually.

Tooling Up for the Job

To install a new roller-furling unit, you'll need a variety of tools. Most of them you'll probably already have in your on-board tool box, but if you don't, you'll want to have them beacuse it will make this job so much easier. Here's the full list of tools the authors used to install their roller furling unit:

Needle nose pliersTo remove cotter pins
Wire cuttersCut headstay
HacksawCut extrusions to length
Rivet gunJoin extrusions & joints
Flat head & Phillips screwdriverAdjust fasteners
Crescent wrenchesInstall Sta-Lok fitting
Measuring tapeMisc.measurements
Rigging tapeTape cotter pins
¼ inch lineSupport extrusions
Plastic bucketContain small parts
Tef-gel metalsApply in rivet hole to isolate

It doesn't take much, but having the right tools can make or break a project like this.

Suggested Reading:

Headsail Reefing Basics by Brian Hancock

Leading Sail Control Lines Aft by Sue and Larry

Installing and Replacing Lifelines by Sue and Larry

SailNet Store Section: Headsail Reefing and Furling Systems


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