770 



Popular Science Monthly 



pole plates and into the mast plates, step 

 a couple of curtain poles. Keeping the 

 center of the mast plates on the center 

 line of canoe, move them forward and 

 backward until both masts have a pleas- 

 ing and identical rake, when the position 

 of the mast plates and their screw holes 

 may be marked on the floor plates. 



The shape of the blanche cleat and the 

 clutch cleat for mizzen sheet both in brass 



After drilling for these, countersink on the 

 under side of floor plates. This permits 

 the removal of mast plates without taking 

 up floor plates as the nuts and washers 

 will be on upper side. 



The floor grating should be cut away 

 as in Fig. 12 if it interferes with the in- 

 stallation of floor plates. Dotted lines 

 under the floor plates indicate portions of 

 two grating strips in way of floor plate. 

 Broken lines along ends of plate show how 

 these, when sawed away may be utilized 

 as cross braces to keep the ends of short- 

 ened strips in place. 



When all steps are permanently fast- 

 ened, re-step the curtain poles. Near 

 lower end of foreward one, and just high 

 enough to keep from marring the deck, tie 

 a brass pulley block with a ^^-in. sheave. 

 Tie another near the mast head so that 

 you can hoist the mainsail as shown in 

 Fig. 13. The governing conditions are 

 that the forward end of boom must not 

 foul forward deck and that the after end 

 of boom must clear head of passenger 

 seated beneath it. The mizzen should be 

 at same height above floor at jaw as the 

 mainsail, boom should have same lift 

 and should clear after deck. Manipulate 

 both sails until these conditions are met. 

 Then mark on the yards the position of 

 halliards and on the masts the positions 

 of upper blocks, and mast plates. These 

 dimensions give you data for your mast 

 specifications. From butt of curtain 

 poles to 6 in. above upper blocks will be 

 length of mast. From floor to flag pole 

 plates they should be cylindrical and 1 ^.j 

 in. in diameter. From flag pole plates to 



mast head they must taper to 13^ in. 

 diameter. Instead of upper block on 

 mizzen mast, a sheave set in a mortise 

 will be an improvement. Let sheave be 

 1 }/$ in. diameter and ^/g in. thick. Mortise 

 to take this should be 2 in. long and 3^ in. 

 wide and its center one inch above place 

 already marked for block. 



When masts are finished, set the 

 halliard blocks with brass screw-eyes 

 which have been opened and closed over 

 the eyes on blocks. Put around each 

 mast, 1 in. above and below each jaw, a 

 leather collar 14 in. thick and 1 in. wide, 

 attached with copper tacks. Soak in 

 water to make pliable before attaching 

 and shellac after they have dried. These 

 collars prevent sails from hoisting too 

 high or booms falling on decks when low- 

 ered. To keep mizzen out of the water 

 when lowered, run an endless line through 

 a screw-eye on masthead and through 

 another one on boom as shown in Fig. 13. 

 Use }4 in- clothes line for halliards and 

 sheets and let main sheet run through a 

 ring on boom and fasten with a snap to 

 a ring lashed to center of thwart. When 

 close hauled, this gives a double purchase 

 and when cast off in running ahead of 

 wind doubles the length of sheet. The 

 mizzen sheet passes through a screw-eye 

 on after deck, as shown in Fig. 13, to a 

 clutch cleat, Fig. 14, placed within reach 

 of the skipper's left hand. To belay 

 halliards, two blanche cleats. Fig. 15, are 

 attached to right hand in-wale within 

 reach of the right hand. That for the 

 mainsail has the hook set aft, and that 

 for the mizzen has the hook forward. 

 {To be continued) 



Freezing a Glass Tumbler to a 

 Block of Wood 



SELECT a small, planed block of hard 

 wood and place upon it a few drops of 

 water and then a glass tumbler having a 

 smooth bottom. Pour about 1 in. of 

 water into the tumbler and add powdered 

 ammonium nitrate, stirring the mixture 

 constantly. As the ammonium nitrate 

 goes into solution, it absorbs heat, pro- 

 ducing a low temperature which quickly 

 freezes the tumbler fast to the block, so 

 that the latter will not fall when the 

 tumbler is lifted from the table. Frost 

 also gathers on the outside of the tumbler. 



