I don't understand the reference to opening holes and slats in the last post - but maybe I'm missing something obvious.
steve5 - A parrel is a simple mechanical device that secures a yard (or gaff, or boom) to a mast in a way that lets the yard (or gaff, or boom) swing with the mast as a pivot, and slide up and down the mast.
In order to function properly, a yard has to be able to swing (so the sail attached to it can receive the wind from different directions) and slide up and down the mast (up when the sail on the yard is set, down when the sail is furled). In the days of the SR, if I'm not mistaken, all the yards had parrels. By the time of the Victory, the lower yards were being held to the masts by heavy rope trusses. But the topsail, topgallant, and royal yards in Nelson's day used just about the same sort of parrels that had been in use a hundred years earlier.
A parrel consists of a bunch of rollers, or beads, a set of ribs with holes cut in them to act as spacers, and a pair of long pieces of rope. The rope gets passed alternately through the ribs and beads, forming a sort of roller bearing arrangement.
This sort of thing is much easier to show in a picture than to describe verbally. Here's a drawing I found in a few minutes of googling: http://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRw&url=http%3A%2F%2Fshipmodeling.net%2Fphotopost%2Fshowphoto9285.html&ei=8WitVJXtOcuiNua1gbgN&bvm=bv.83134100,d.eXY&psig=AFQjCNEUrfxjmjWCmDr0_RsYD9WzOO9Wkg&ust=1420737108850921 .
Here's another: http://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRw&url=http%3A%2F%2Fwww.duyfken.com%2Fimage-gallery-1%2Fduyfken-and-svanen-on-sydney-harbour&ei=PGmtVLmpB4KxggS5xYKQAQ&bvm=bv.83134100,d.eXY&psig=AFQjCNFw4FqxfllJnyP3gH0nUCO-AWw80w&ust=1420737189346460 .
It's easy to make parrels on 1/100 scale. The ribs can be made of either wood or styrene, and the rollers from small glass beads.
As I've said several times before in this Forum, to build a model of a ship like the Victory with minimal stress and headaches you really need at least one good, basic book with drawings that show how the ship actually worked. The instructions in the Heller kit are awful; they apparently were written by somebody who knew mighty little about ships. (The English "translation" usually packed in kits for British and American distribution are worse. The person responsible for them, it seems, neither understood French nor had tried to build the model.) The old, standby source of information on this ship is C. Nepean Longridge's The Anatomy of Nelson's Ships. There are a number of other good books on the subject; we've covered them here in earlier Forum threads.
For a good, basic description of how sailing ships work, I highly recommend George Campbell's Neophyte Shipmodeler's Jackstay. It dates from the 1960s, and is primarily aimed at modelers working from solid-hull wood kits. But the basic information in it is valid for any sailing ship model. And I know of no better introduction to the fundamentals of sailing ship-era nautical terminology. Learn everything in that little book, and you're well on your way to being a knowledgeable ship modeler.
The best news about Campbell's Jackstay: it's cheap! Here's a link: http://www.modelexpo-online.com/product-p/msb110.htm . If you're only going to keep one book on your workbench, that's the one I'd recommend.