It’s easy to lock them when the sail is hoisted, he says, but when you go to take it down, when the halyard is under extreme loads, especially on bigger boats, as you pull the halyard up to take it off lock, you don’t know if you’re just stretching the halyard or whether the unit is simply not working. “You have to somehow know that the triggers are moving,” he says. “Moving the halyard a few millimeters to trip the lock can be tough. You just don’t know when you’re beating the inherent stretch of the halyard.”

For buoy racing, they can be more of hindrance than a help, says professional rigger Brian Fisher, of Rig Pro: “Many of the TP52s don’t use them—with the exception of the coastal races—because the whole sequence of getting off the lock can be complicated.”

The solution Hall is currently working on is a system that uses a miniature magnetic proximity sensor, integrated into the lock unit, to transmit a signal to a deck display, showing whether the unit is in locked or unlocked status.

But of the benefits, Hall thinks primarily of performance and repeatability with settings. With the halyard always set to a fixed-hoist point, luff-tension adjustments can be made with jib-cunningham systems; hydraulic or otherwise. And making a case for further harnessing the wind’s power, says Hall, consider that, as a spinnaker pumps, the halyard stretches, and, in theory, the rope is absorbing the energy, not the boat. “If the halyard is locked, that energy pushes the boat,” says Hall.

There’s also the important issue of preventing halyard chafe; the sawing effect of highly-loaded halyard over a sheave or other turning point can be a major headache over many ocean miles: with locks, at least, there’s no need to regularly change the halyard position.

The lock unit itself has been a challenge to get right, Hall admits. The company is on version five (and 2 to 3 years with the current concept), but they’re happy with the reliability. In terms of maintenance, a lock is like a winch: if you leave it exposed over the offseason it will need to be cleaned and lubricated before use, and even if it’s regularly used, one will eventually need to be lightly serviced.

While the cost of the units (Hall’s smallest 2-ton external unit costs $4,600), has kept widespread use in check, the most significant hang-up for would-be customers is that daunting potential for it not to unlock when a sail needs to come down. Getting the bullet placement right was a problem of the past, one that they’ve worked to eliminate. “Initially, we caused our own problems by not educating the riggers early on about how to splice the bullets,” says Hall, “but we’ve figured that out and it’s no longer an issue.”

One common notion about halyard locks is they reduce compression on the mast, thereby allowing for a lighter mast, and also the possible use of smaller diameter halyards, yet another weight savings. “On big-boat masts compression is not an issue at all,” says Hall. “Maybe with a masthead spinnaker on a fractional rig it might help.”

And when it comes to looking to locks as a means of downsizing halyards, Hall also cautions against this idea: “The limit is the weight of the sail,” he explains. “Sure . . . you could pull it up with string, but we encourage the use of regular-sized halyards so you don’t have to worry if the lock stops working—you could still hoist and rely on the halyard. Also, a lot of time; on a long leg you may take the sail off the lock early, in time to douse, so you would need that halyard to hold the load.”