infomiation derived tram, their examination makes it possilDle to determine 

 the hreedlng season and the rate of growth of the various marine Taorers 

 and other organisms which are active. 



5. In some places vhere the marine horer attack has "been 

 unusually destructive it has been found impossihle to leave the panels 

 suhmerged as long as 8 months, as they are frequently more or less 

 completely destroyed within this period, of time or less. Increasing the, 

 thickness of the panels from one to two, and even to four, inches has 

 been tried. However, it was soon found that this did not increase 

 their length of life since the thicker the wood used, the greater was 

 the number of borers in the panels, so that the infestation was just as 

 severe proportionately in the thicker panels as in the thin ones. 

 Recourse was then had to using a board holding only k test panels and 

 the control panel. By using this board, the period of submergence, can 

 be reduced from eight to four months. In a few locations, however, as 

 at Mayport, Florida, it was found necessary to reduce the period of 

 submergence to 3 months in order to have panels to remove that would 

 not be completely destroyed. 



AI.O9 Specifications and Procedure for Construction and Operation of 

 Standard Test Boajr'ds for Marine Borer Investigation 



1. A "Test Board" shall consist of an assembly of nine "test 

 panels" mounted on a metal support bar as shown on accompanying. sketch. 

 Figure 12, entitled 



STANDARD TEST BOARD 

 FOR MARIHE BORER 

 INVIBTIGAnOlSr 

 W. F. Clapp Laboratories 

 •SYBE 2 



2. The support bar shall preferably be a 1^" x ■5-" x 6*-k" long 

 steel bar, although a steel pipe or any other suitable section will serve 

 equally veil if a bar is not available. Wood shall not be used for the 

 support bar. 



3. Test panels shall be 6" x 12" x 7/8" or 1" thick S.U.S, of 

 comparatively light, soft wood, preferably pine, and shall be straight- 

 grained and free from knots. 



» 



k. Each panel shall be numbered in a manner which will be 

 permanent. A metal tag, stamped with the appropriate number or symbol, 

 and fastened to the panel by means of 2 nails, shall be used* If metal 



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