Navy Department 

 Bureau of Yards and Docks 

 WasMngton, D. ,C., April 1951 



From painstaking research, such as is sunnnarized in this 

 report, we hare learned in recent times that most of the world* s 

 coastal waters are Infested more or less with destructive marine 

 horers. Some costly marine structures htiilt in the last decade 

 without due appreciation of the marine horer menace have "been 

 totally destroyed "by their attacks. In other cases, structures of 

 a relatively temporary nature have req.uired extensive repairs after 

 only two or three years of service. 



Detailed knowledge of the "biological conditions in a given 

 harhor is indispensahle to those who are concerned with any type of 

 marine structure containing timber. 



Before a marine structure is designed or constructed, it is 

 extremely important that the degree and type of local infestation he 

 accurately determined and that specifications he eatahlished which 

 will assure its resistance to horer attacks. After it is erected, it 

 is equally in^ortant to maintain regular, thorough inspections and 

 tests if horer damage is to he averted. 



It is 'the helief of the Bureau that the information in this 

 report will he of value not only to those officers of the Civil 

 Engineer Corps who have cognizance over harhor Installations, hut 

 also to all others who are concerned with shoreside construction and 

 the maintenance of timber marine structures and/or the relatively safe 

 herthing of wooden vessels. 



' , JeZlej 



AdA. (CEd^), 

 31" of Bureau of Yards and Docks 





