Tim:
The Skerry is a lovely boat. I'll put in a plug for the lug here.
First, a balanced lug like this is a very practical arrangement for a small boat meant to be rowed as much as she's sailed. No standing rigging (shrouds or stays), short spars, simple running rigging (at least in small sizes), and the yards and sail are easily bundled up and cleared away so as not to interfere with rowing. It is child's play to set or strike the short mast. In my PMD (lug similar to the Skerry's lug option), the mast is just a bit longer than the boat, but not difficult to secure out of the way for rowing. We could have an even shorter mast with a similarly sized spritsail (such as the original, I believe, Skerry rig), but that is otherwise a less handy arrangement than the lug and, in my limited experience with spritsails, one never seems to be done setting up the peak sprit snotter.
Second, a well-set balanced lug pulls like a mule, with the center of the sail area down low to the boat relative to other choices. The "well-set" business is the trick here. Since the rig has not been as common here in the U.S. as elsewhere in the world, the fine points of getting the best out of the sail are perhaps not as well understood as with more common rigs, such as the gaff rig, gunter, or various varieties of jib-headed, Bermudian, Marconi, pointy mainsail sloops which are so ubiquitous. It's all about getting the attachments for halyard and downhaul located in the sweet spots on the yards and then being able to get appropriate tension over the sail between the upper and lower yards to get the best shape in the sail. This may take a bit of experimenting. (That's why, on our PMD, halyard and downhaul are attached to little loops lashed to the yards so they could be shifted as I fined tuned the thing over time.)
Third, it is hard to beat a balanced lug for straightforward reefing which results in a well-shaped sail for resetting, with as little rigging left standing above the reefed sail to create unhelpful windage.
Finally, I don't think the reputation of the lug rig as being substantially less weatherly than other possibilities is as well deserved as commonly thought. A poorly cut or set sail of any sort will expose all its faults when trying to get upwind. After all, any bonehead in a bathtub with bedsheets on broomsticks can sail downwind; it's the upwind work that separates the broomsticks from the spars, the bedsheets from the sails, the bathtubs from the sailboats...and the boneheads from the sailors! If the sail isn't cut by a sailmaker who understands the rig (Doug Fowler's sails as supplied by CLC are superb!), it may not perform well, especially to windward. Getting good windward performance out of a lug sail is all about getting a taut luff (tricky, since it is not attached to a spar) without getting an over-taut leech in the bargain, and keeping good tension across the sail so it doesn't go baggy and start looking more like a bedsheet on broomsticks. As the wind strength increases, it is important to increase the downhaul tension to (1) counteract the increased pressure on the sail and (2) introduce a bit of flex in the yards so as to flatten the sail out somewhat. The mast is a pure compression post, and must be very stiff for all this to work, since things will go baggy if it flexes too much.
When I've got all this working correctly in our PMD, she will make 4.0 to 4.5 knots hard on the wind (45 degrees or maybe a bit more) when it's blowing something over 10 knots (just short of needing the first reef), pretty much headed where she's pointed, i.e., not making excessive leeway. Will she point with an E Scow with her high-tension rigging humming like a giant harp? Heck, no, but it ain't bad for an eleven and a half foot rowboat with...what?...maybe a nine foot waterline and a low-tech-is-go-tech rig.
When we chose the lug rig for our PMD, we were thinking of the sailing as being auxiliary to the rowing, not the other way 'round, so we were willing to trade some upwind sailing performance, if that was the case, for keeping the boat clear for rowing. We didn't expect her to be a dog, by any means, but we were very pleasantly surprised by how well she sails to windward.
For small boats meant both to row and to sail well, I am now a confirmed "lug nut" for sure.
.....Michael
On the Goat, a parrel is not needed for the yard because of the way the main halyard is rigged. The halyard is tied to the forward end of the yard via a hole and stop knot. The halyard then runs up/aft, around the mast then through a block lashed to the yard before to goes through the mast head and down. As soon as the halyard is tentioned, the halyard itself acts like a parrel. Again, hard to explain but it is easy, cheap and works well. 