Sail Trim: Rigging Adjustable Sheet Leads
I’ve always been less than enthusiastic about changing my genoa sheet leads on different points of sail. I know I should move the lead forward to improve its shape when I’m reefing or sailing off the wind. However, when I’m sailing singlehanded it is a bind to release the genoa sheet, go forward, kneel on the sheet, drag the car forward, go back and then winch the sail in, only to find I’ve either over-or-under adjusted the thing and need to perform the procedure all over again. The time lost messing around usually outweighs any performance advantage I may have gained.
That said, I’ve spent a lot of money on my sails, so it’s only right I should at least try to get the most out of them. However, my boat is a child of the ‘80s, and her old genoa track isn’t compatible with the fancy roller-bearing genoa cars of today. And neither, if I’m to be totally honest about it, is my wallet. (A rough calculation for new tracks, cars, track ends, jammers and lines comes out at over $1,000.) Beyond that, my Sadler 32 has a molded fiberglass inner headliner, so I would have to hope and pray the nuts, backing plates and washers were all encapsulated and that the bolt spacing was the same. Even if I could justify the expense, the prospect of replacing the tracks was too intimidating to consider. Still, I wanted to adjust my genoa cars from the cockpit.
Luckily, I am in the position of being able to sail a lot of different boats, both new and old, fast and slow, so I started looking at what other singlehanded sailors have done to solve this problem. I’ve sailed on Open 60s, for example, that use a large low-friction ring to restrain the sheet, which itself is held in position by two or three control lines that can be winched in or eased as necessary. Low-friction rings are aluminum “donuts” with a smooth inner hole, with a groove around the outside. They are much cheaper than turning blocks, have no moving parts and hang off racing boats like baubles on a Christmas tree. In many situations, they can replace blocks completely.
It wasn’t until I went out with British professional sailor Sam Goodchild, however, that I had my eureka moment. Sam sails his 32ft Beneteau Figaro II singlehanded, so all lines are led back to the cockpit, within easy reach of the helm. Although Sam had a short athwartships genoa track running from inboard to outboard across his deck, the lion’s share of the adjustment was done using a low-friction ring and two control lines, both adjusted by hand.
It was the last part that was most interesting; by using cascade tackles, the loads on the lines were reduced enough to be manageable without having to resort to the mechanical advantage of a winch. All a genoa car does, after all, is adjust the angle at which the sheet is pulled in. This can also be achieved by pulling the sheet down at a fixed point, a perfect application for a low-friction ring.
After sailing with Sam, I started looking into cascade block systems, load ratios and costs. Harken has a good load calculator on its website (harken.com) so after finding out your boat’s I and J measurements and working out its sail area, you can calculate the sheet load for any given wind speed. The load on the car is then usually between 0.3-0.5 of the sheet load. With a full genoa in 25 knots of wind, for example, my boat’s sheet load was 847lb, while at 30 knots it was 1,221lb.
Having figured out the forces I had to contend with, the next step was to decide on the rings and lashings. To get the most out of the low-friction ring, the radius of its inner curve should be at least 1.5 times the diameter of the rope: which meant 20mm, or 3/4in, for a main control ring to accommodate my 12mm sheets. For the control lines, I found a sizable hank of 3.5mm (1/8in) Dyneema, with a breaking strain of over 2,200lb, for $15.
One time at a boat show, I also noticed a Pogo 12.50 racer-cruiser that had its control lines doubled up through the low-friction ring, giving twice the purchase and allowing a smaller low-friction ring to be used at the base. This seemed like a good approach to use on my boat as well, so I decided to run the numbers for it as well.
Based on the aforementioned loadings and lead corrections, the load through a car on my boat with full sail in 30 knots would be between 365-600lb; however, by 30 knots I would also be down to at least two reefs. I could, therefore, use a smaller low-friction ring as a turning block at the deck and another one in a 2:1 purchase to adjust the control line for the ring height, halving the load again. The rings I had in mind have a safe working load of 660lb, and even if one should ever disintegrate, the control line would still be held in position by the lashing.
That done, I now had to decide where to secure the system to the deck. I considered using the genoa car as a turning block, but with the control line being so thin I discounted it. (I also liked the idea of being able to revert to the original system if anything went wrong.) There was a handy midships mooring cleat attached to the forward end of the genoa track that I could lash things to while I experimented. If the system worked I could work out a more permanent solution.
So far I’d spent around $30 on two low-friction rings (I had a third ring that I use as a turning block for my spinnaker) and $15 on my bargain hank of Dyneema, all of which could find another use should it all go awry. All that remained was to put it all together and see how it worked.
On the day of the first test, I had a good 20 knots of wind to test the system. Initially, I had a 2:1 purchase to pull the ring down and another 2:1 purchase to pull that line aft. It soon became apparent that more purchase was called for. So I doubled up the downhaul to a 4:1 purchase and kept the control line at 2:1; this gave a final ratio of 8:1, which was just about manageable by hand.
Unfortunately, the control lines kept getting caught on the cleat horns, and the 5mm control line was too thin, so another solution was clearly needed. I thought about using an eye bolt, but the thought of securing it through the headliner put me off. In the end, I bought a car with an eye and a plunger/pin adjustment and lashed the lower, smaller low friction ring to it using the 3.5mm Dyneema. The system was ready to test again, and it worked well. I also figured out the best position on the coaming for the camcleat that holds the control line so I can use the system from the cockpit.
After sailing with this setup for a season, I am pleased with it. Not wanting to foul my decks, I’ve kept the system down to one control line, as opposed to opting for two or even three to fine-tune the lead inboard or outboard the way racing crews often do—she is, after all, a cruising boat. If I ever feel inclined to rig a barber hauler from my toerail, I can always attach it to the low-friction ring.
One thing I remain wary of is the possibility of the large ring taking chunks out of my cabintop or even smashing through a portlight due to a flogging sheet. However, before tacking or furling I usually bring the leeward ring down to the deck, since it is easier to ease once there’s a bit of tension on the sheet than to bring it in after the sail is full.
The system wasn’t quite as cheap as I was hoping for—coming in at around $300 in all—but much of that was spent on genoa cars and uprated jammers; I could have easily done the same job for half that. Because adjustment from the cockpit is now so simple, I’ve found another thing I can easily tweak when I’m sailing, just to get the best out of my boat and her sails.
Photos by Graham Snook; illustration by Pip Hurn