Here’s the MKII Testbed for USA 1. I’ve shown some details in the hope they’ll inspire or help others with their boats. I went back to a full deck this time in interest of weight and simplicity. Total displacement is 980 gr with 4 NiMH AAs on board, 450 of it in ballast. After I gain experience with this layout I’ll do a new deck with film-covered cutouts to save a few more grams.
The shot on the stand shows the aft placement of the fin; this, along with the 50% jib, is designed to get the mast aft of the Longitudinal Center of Flotation so that mast downforce tends to pitch her up (there has been dispute amongst NAs and others for decades whether this is science or voodoo, but I believe it happens). The picture of here under sail shows the characteristic squat this trick achieves.
These were my first attempt at paneled sails, broadseamed over a sail block using the heat-setting adhesive tape from Hang-em-high kite supplies. The jib is carried by a rigid forestay and is controlled by a jib radial. The mast bend is controlled by a single diamond stay using spreaders swept back at a 15 deg angle. As a result no backstay is required, and compared to “traditional” rigs, the jib boom moves with the tiniest effort of the wind. This, and the big jib (IMHO) means she tacks smartly through the eye of the wind. The pictures show the jib radial, carved from ABS, and the masthead fittings, including the upper vang and the main and jib luff tensioners. All tensioning on the rig is done with Dubro “rigging couplers,” 4-40 for the diamond stays and the single shrouds and 2-56 for the luff tensioners. The running rigging shown is temporary until I’m convinced I’ve got the mast in the right place, which appears from early sails to be the case.
The radio layout follows the one that has worked without a glitch for five years on Yankee III. The sail winch hangs from the removable deck as shown. The power from the winch arm is transferred to a “racetrack” sheet which runs around the underside of the deck, coming up and going back down as shown through a pair of fairleads. The sheet is guided by “Linville blocks,” tubing trapped in wood as shown. This layout enables things to be checked out on the bench. The deck is held down with #0 x 1/4" screws from Microfasteners and the hull/deck seam is sealed with Stik-Tack, which again I’ve used on Yankee III for years. It’s been my experience that switches have been a main cause of radio failures so the receiver is turned on and off by plugging and unplugging it. The hatch is the one I’ve described in another post.
Well, that’s it. I hope this gets you thinking about all the cool things you can do with this class and I hope to see you in Albuquerque in October.
Cheers,
Earl
Actually, the terrific thing about this class is the ability to economically try out things you’ve seen done elsewhere or think of as unique.