Handling tension/slack with moving winches

Previously, tension on the braces was maintained by springs, elastic, or weights, on the braces. Another way, that I use on my 1:36 scale Constellation; is to move the winch itself to compensate. That's the premis behind the sliding brace winch:

The winch servo is mounted on blocks that slide on rods pushed by springs which are also on the rods. The springs only need be strong enough to push the servo back against the slack in the brace. If the springs are too stiff, the system may jam, or cause damage somewhere else. In this case, the winches are horizontal which actually makes slack more of a problem, as the braces are more apt to run off their part of the drum because of sagging slack in the brace. Any winch system should have a fairlead onto the winch-drum, whether the servo moves or not.

A second fairlead is needed as shown, because the braces go off in various directions to get to their yards, and would interfere with the servo's movement on it's rails without this fairlead to guide them straight to the servo-mounted fairleads.

It may not appear so in the photos, but there are no mods to the servo itself; it's simply mounted on plastic blocks by it's normal mounting spots, so there's nothing to void the servo's warranty, and it's fairly simply to remove or replace it, with just a small screw-driver. Also note there's a block mounted on the winches fairlead called a drum torque block; this supports the winch-drums for pulling to one side possibly over-working the servo. Also note, all the winches only bace the tops'l yard on each mast; fore on one winch; main & mizzen on the other.

Another note, with winch bracing, there's going to be lines moving through fairleads; eyes, tubes, rings, pulleys, etc, below deck until they emerge above deck to get to the yards they control, where they may be passing through even more fairleads.

The image below is a schematic of the routing of Constellation's control lines below deck, most of which are screw eyes in the deck beams, to get them to were they come through the deck. That's a lot of line rubbing and making friction; so much so that when I was testing using natural fiber cord, it wouldn't move at all! Replacing that cord with polyester sail-thread (Dacron) that I ropewalked into 3-stranded line, worked, and still works perfectly.

I also don't actively brace all the yards, only the fore, main, and mizzen tops'l yards. The t'gallant and royal sails are designed to be removable, yard and all, to reduce sails for weather conditions. The courses bunt up. The sails the other yards and sails along. Running the brace to the tops'l yard puts it in the middle of the stack. The tops'l also have bowlines which help pull the course yards along.

Some video of the sliding brace winch in action.

A similar set-up without moving winches is to have the motors or servos drive the drums on an axle. Albert Lheureux used such a system in his Rattlesnake back in 1984. The various o-rings and pulleys allowed slippage when lines got to the end instead of using limit-switches to stop the motors.

Horizontal mounted winches using drums with large flanges, are more forgiving of small amounts of slack in the braces. I began thinking of going this route for my Macedonian, basically turning the winches used on Constellation on their sides, as demonstrated in this 3D model:

Georg Reinbold uses a more modular, version of this system in his bark Nernberg (1:75 scale, I think). Using sized drums, to get the right pull length for each yard, as detailed previously in the drum-making section; and large flanges to keep everything in it's place. His set-up is actually quite simple, and modular, so it's easy to maintain or repair. He actively brace every yard, prototypically, on two winches/channels, which adds a little complication. To tension the braces, Georg uses plastic ring attached to elastic. Because, below-deck, the braces past through tube, rings, eyes, etc; there's a lot of friction, so he recommends using a PVC braided cord, saying natural fiber will wear quickly and anything else will bind. I've found that polyester sail-thread (Dacron) walked on a ropewalk into rope works better as it presents less surface area than braided cord, hense, less friction.

There's a two drums for each mast, one for it's port brace, the other for the starboard brace. As explained on the previous page, each drum is sized to pull or pay out the requisite length in the number of rotations the drum will make. What I could not find was how he attaches the braces to their drum, I suspect they may be glued.

I'm leaning toward this set-up in my 1:36 scale frigate Macedonian as opposed to what I used in Constellation primarily because it's easier to handle the sheets/tacks of the course sails (with no yard below them). I'll diagram and explain all that later.