W. H. LEGGETT.--What you have made is a truss, not slings at all. Slings are chains running from a mast-head cap down through the hounds, and are used to support a lower yard which is fastened to the mast by a truss, and is not intended to be raised or lowered. A yard which is to be hoisted and lowered should be secured to the mast by a parral of leather, and should be raised by lifts and halyards. (2.) Clew-lines lead from the deck through a clew-block under the yard, and through the clewline block in the sail, the standing part being taken between the head of the sail and the yard, and made fast to the arm of the truss. (3.) Lead the braces to the main-top. (4.) Your dimensions are not good, unless your draught is to be increased by a heavy lead keel. Your proportion of more than five beams to the length is bad. She ought to have more beam--say, sixteen inches. The capstan ought to be on the forecastle-deck. The dimensions of spars are good. FRANK J. SMYTH.--Such a set of rules as you ask for would occupy too much space in this paper. The racing rules of the American Model Yacht Club were printed in _Forest and Stream_ for November 24, 1894. Send ten cents and postage to the office of that paper, 318 Broadway, and get a copy. HERBERT ARNOLD.--Dimensions of a good dory would be sixteen feet long on the bottom, seventeen feet over all, three feet six inches wide on the bottom amidships, four feet eight inches wide at the gunwale amidships, and two feet deep. You could not have a safer boat in any waters. [Illustration: STAMPS] This Department is conducted in the interest of stamp and coin collectors, and the Editor will be pleased to answer any question on these subjects so far as possible. Correspondents should address Editor Stamp Department. [Illustration]