Condensed from an article by H. Percy Ashley in Rudder.
The plans and specifications shown in the illustrations are for making a 400-ft. class ice-yacht, having a double cockpit to accommodate four persons. The weight of the persons in the forward cockpit keeps the boat from rearing when in a stiff breeze. The forward cockpit can be removed if necessary. The materials used are: backbone, white pine; center, clear spruce; sides, white oak caps; runner plank, basswood, butternut or oak; cockpit, oak; runners, chocks, etc., quartered white oak. All the iron work should be first-grade Swedish iron, with the exception of the runners, which are soft cast iron.
Illustration: Ice-Yacht Complete
It is not necessary to go into detail with the measurements as they are plainly shown in the sketches. The backbone is 37-1/2 ft. over all, 12 in. in the center, 5 in. stern, 3-1/2 in. at the nose; width 4-1/2 in. All wood should be selected from the best grades, well seasoned and free from checks. In Fig. 1 is shown the complete ice-yacht with general dimensions for the sail and main parts. Other dimensions are shown in Fig-, 2. The backbone is capped on the upper and lower edges full length with strips of oak, 4-1/4 in. wide and 5/8 in. thick. The lengthwise side strips of spruce are 1-1/4 in. thick. The filling-in pieces placed between the side pieces are of seasoned white pine, leaving the open places as shown in Fig. 2. The parts are put together with hot glue and brass screws.
The runner plank should be placed with the heart of the wood up, so as to give the natural curve from the ice so that it will act as a spring. The plank is 16 in. wide in the center, 14 in. at the ends; 4-1/8 in. thick at the center and 2-3/4 in. at the ends.
Illustration: Details of the Ice-Yacht Parts
Details of the runners are shown in Figs. 3, 4, 5, 6, 7, 8 and 9. The cast iron shoes are filed and finished with emery paper, making the angle on the cutting edge 45 deg. on both sides. The runners are 7-1/4 in. wide over all and 2-1/8 in. thick. The soft iron casting is 2-1/4 in. deep. The shoes are fastened by 5/8-in. machine bolts. These are shown in Figs. 3 and 9. The rudder is 2-3/4 in. thick, 5 in. deep, including wood and iron, and 3 ft. long. The cast iron shoe is 1-7/8 in. deep and fastened on with four 1/2-in. machine bolts. A brass plate, 1/4 in. thick, 2 in. wide and 7 in. long, is inserted on each side of the runners as shown in Fig. 9. Three holes are drilled through for a 3/4-in. riding bolt that can be shifted as desired for rough or smooth ice. The runner chocks and guides are 1-7/8 in. thick and 4-1/2 in. deep. They are set in the runner plank 1/4 in. and fastened with glue and 1/2-in. lag screws. These are shown in Figs. 6 and 7.
The aft cockpit is stationary, while the fore or passenger cockpit can be removed at will. Both cockpits are the same size, 42 in. wide and 7 ft. long over all. Each one has a bent rail, 1-1/2 in. by 4 in., grooved 1/2 in. by 7/8 in. before bending. The flooring is of oak, 1-1/2 in. thick and 4 in. wide, tongue-and grooved. The forward cockpit is made in halves and hung on the backbone with wrought-iron straps and bolts. These are shown in Figs. 41, 43 and 44. Two pieces of oak, 1/2 in, by 4 in. are fastened with screws to the flooring, parallel with the backbone in the forward cockpit. The runner plank which passes under this cockpit gives it stability.
The spars should be hollow and have the following dimensions: Mast, 23 ft. 3 in.; heel, 3-3/4 in. ; center, 5-1/4 in.; tip, 4 in. ; boom 23-1/2 ft.; heel, 3-3/4 in.; center, 4 in. ; tip, 2-7/8 in. at ends; gaff, 12-1/2 ft.; center, 3-1/2 in.; ends, 2-1/2 in.; jib-boom, 10-1/2 ft.; 1-3/4 in. at the ends, 2-1/8 in. at the center. The gaff is furnished with bent jaws of oak, Fig. 17, and the main boom with gooseneck, Fig. 12.
Galvanized cast-steel yacht rigging, 5/16 in. in diameter, is used for the shrouds; jibstay, 3/8 in. in diameter; runner plank guys, 5/16 in. in diameter; bobstay, 3/8 in. in diameter; martingale stay, 1/4 in. in diameter. The throat,and peak halyards are 3/8 in. in diameter; jib halyards, 1/4 in. in diameter.
The main sheet rigging is 9/16-in. Russian bolt rope; jibs, 7/16-in. manila bolt rope, 4-strand; jib-sheet, 3/8-in. manila bolt rope. Four 1/2-in. bronze turnbuckles, Fig. 34, are used for the shrouds; one 5/8-in. turnbuckle for the jibstay and one for the bobstay; four 3/8-in. turnbuckles for the runner plank stays, and one for the martingale stay.
Two rope blocks for 3/8-in. wire rope, Fig. 10, are used for the peak and throat, and one block for the wire rope 1/4 in. in diameter for the jib halyard. Four 6-in. and one 7-in. cleats, Fig. 18, are used. The blocks shown in Fig. 11 are used for the main and jib sheets. The steering arrangement is shown in Figs. 4 and 5. The tiller is 3-1/2 ft. long; rudder post, 1-1/4 in. in diameter; shoulder to lower end of jaws, 4 in.; depth of jaws, 2-7/8 in.; length of post including screw top, 12 in. The rubber washer acts as a spring on rough ice.
In Figs. 13, 14, 15 and 16 are shown metal bands for the nose of the backbone, and Figs. 19, 20, 21, 22 and 23 show the saddles that fit over the backbone and hold the runner plank in place. There are two sets of these. A chock should be sunk in the runner plank at each side to connect with the backbone to keep it from slipping sidewise as the boat rises in the air. The martingale spreader is shown in Figs. 24 and 25. Straps through which the ring bolts for the shrouds pass on the ends to fasten the turnbuckles for the runner plank guys are shown in Figs. 26 and 27. The bobstay spreaders are shown in Figs. 28, 29 and 30. In Fig. 31 is shown the top plate for the rudder post and in Figs. 32 and 33, the lower plate for same. The mast step is shown in Figs. 35, 36 and 37. Two positions of the jib traveler are shown in Fig. 38. The anchor plate for the bobstay under the cockpit is shown in Figs. 39 and 40.
At the nose and heel the runner plank guys end in a loop. The bobstay has a loop at the nose and ends in a turnbuckle that fastens to the anchor plate under the cockpit, aft. The shrouds, jibstay and martingale have loops at the masthead and are spliced bare over solid thimbles. The loops are finished in pigskin and served with soft cotton twine over the splice and varnished. The parceling is done with insulating tape. Serve the tiller with soft cotton twine and ride a second serving over the first. For the halyards hoisting use a jig shown in Fig. 46. The thimble shown in Fig. 47 is made by splicing the rope to the thimble at running part of halyard and passing back and forth through cleat and thimble. This gives a quick and strong purchase and does away with cumbersome blocks of the old-fashioned jig. The jib-sheet leads aft to the steering cockpit. The main-sheet ends in a jig of a single block and a single block with becket.
Be sure that your sail covers are large enough--the sail maker always makes too tight. The cockpit covers must fit tightly around the cockpit rail. Many boats have sail and cockpit covers in one piece.
The woodwork may be finished as desired by the builder. The dimensions of the sails are given in the general drawing, Fig. 1.