Page 155 control and signal building 2721 



the desired height is reached. Braces should be cut as needed so that allowance can be made for slight 

 variation in cross section and the spacing of the horizontal braces. No attempt should be made to 

 cut the lumber to dimensions and shapes on board the ship or before the signal is erected. To do so is 

 a waste of time and lumber because the pieces cannot be made to fit correctly since signal building is 

 not a precise engineering feat. The signal may not be started truly vertical or the sides and legs may 

 not be precisely parallel. These defects can be remedied as the work proceeds if the lumber is cut as 

 used, but cannot be remedied if dimensioned pieces are used because they will not fit. 



The target is composed of 40 to 60 boards spaced 4 inches apart. These boards are }i by 6 inches 

 by 12 feet in size, joined in groups of three. Vertical strips 2 by 2 by 26 inches are nailed 2 feet from 

 the outer ends of each group of target boards to serve as stiff eners and to which wires can be fastened 

 to draw the ends of the target toward the landward side of the tower, so it will present a convex sur- 

 face to seaward. 



The target boards should be covered with two coats of paint or with signal cloth tacked on each 

 board. Experience has demonstrated that white signal cloth reflects sunlight better than white 

 paint. If the boards are painted, it should be done on board ship because ashore it is difficult to 

 prevent sand or dirt getting on them before the paint is dry. 



The guys are made of No. 8 galvanized iron wire. Four guys are placed at the 40-foot level, lead- 

 ing away from the four corners of the structure, each in a direction in line with the corner diagonally 

 opposite. Eight guys are placed at the 60-, 80-, and 98-foot levels; four leading from the corhers as 

 at the 40-foot level, two leading seaward from the seaward corners, and two leading landward from the 

 landward corners. The corresponding guys at the 40- and 60-foot levels are fastened to the same set 

 of anchors. Likewise, the corresponding guys at the 80- and 98-foot levels are fastened to another 

 more distant set of anchors. The directions of the guys may be varied for additional protection 

 against the prevailing winds, but the greatest wind pressure is always against the target. 



For anchoring the guy wires, timbers or deadmen are buried in trenches 3 feet deep which are 

 dug 40 feet from the tower for the 40- and 60-foot level guy wires and 80 feet for the 80- and 98-foot 

 level guy wires. An anchor timber should be not less than 4 by 4 inches by 8 feet in size. It is 

 laid in the trench which is filled with earth up to the level of the top of the timber except in the center. 

 Short pieces of lumber are then nailed across each end of the timber and the ends of the trench are filled 

 in, leaving the middle open until the guys have been made fast. More pieces of lumber are then nailed 

 across the middle part of the deadman and the trench is filled. 



About 2)^ days should be allowed for building a signal of this type and size, about 

 half of the time being consumed in landing the lumber and other materials from the 

 vessel and getting them to the site. This will natia-ally be the point of highest eleva- 

 tion in the immediate vicinity and may be some distance inland. The actual con- 

 struction can be done very rapidly in fairly calm weather, especially if there are several 

 experienced men in tlie party. It is practically impossible to handle the target boards 

 in a moderate wind. 



(A) SPECIFICATIONS FOR NINETY-EIGHT FOOT SIGNAL 



The specifications for the 98-foot signal are as follows: 



Cross section.— Four feet square. 



Height.— Total 104 feet, the lower 6 feet being buried in the ground. 



Legs. — Four by four inches, built up of 2- by 4-inch lumber, with joints overlapping at least 4 feet and strengthened by 1- by 

 4-inch by 3-foot pieces nailed over the splices. 



Horizontal braces. — Two by four inches for the lower 16 feet and 1 by 4 inches above, spaced 4 feet apart. 



Diagonal braces. — One- by four-inch boards cross-braced on the lower three panels; single and zigzagged above. 



Target.— Of ],i- by 6-inch by 12-foot boards in groups of three spaced 4 inches part, with 2- by 2- by 26-inch vertical strips to stiffen 

 the outer ends and to which wires may be attached to arch the target. 



Anchors. — Size 4 by 4 inches by 8 feet, buUt of 2- by 4-inch pieces, utilizing those with the most knots. 



Guy wire. — No. 8 galvanized iron wire. 



(B) LIST OF MATERIALS FOR NINETY-EIGHT FOOT SIGNAL 



Description Size Number required 



Lumber, S4S 2" by 4" by 16' 80 pieces. 



1" by 4" by 14' 120 pieces. 



1/2" by 6" by 12' 40 to 60 pieces. 



Lumber, scrap 1" by 12" by 14' 6 pieces. 



2" by 2" by 16' 4 to 6 pieces. 



Wire, galvanized No. 8 3,500 feet. 



Miscellaneous Paint and brushes or signal cloth and tacks. 



Nails, rope, saws, hammers, shovels, etc. 



