BOAT AND BARGE CONSTRUCTION 



519 



to meet the requirements of each par- 

 ticular charge. Fourth, it is possible 

 to plug the ends of the timbers and 

 thereby retard the absorption of mois- 

 ture. Fifth, the penetration of oil is 

 far more uniform. The last two fac- 

 tors tend to eliminate the so-called 

 "working" of the timbers. This is an 

 important item in barge construction, as 

 it is a well-known fact that a barge built 

 of green untreated lumber will usually 

 cause trouble from leaking, due to the 

 subsequent shrinkage of the timber as 

 it dries, and the consequent opening of 

 the seams and loosening of the oakum. 

 Even after the lumber has once become 

 dry it readily absorbs moisture during 

 a wet period and again gives it up dur- 

 ing a dry period, and as a result an 

 untreated barge is re-calked every year 

 after its fourth or fifth year in service. 

 The pressure treatment has largely 

 eliminated this re-calking, and so ma- 

 terially reduced the cost of repairs. 



In conclusion I will state that the 

 original cost of a steel barge with in- 

 terest on the investment is not com- 

 pensated for, by the added life, com- 

 pared with a creosoted barge. That the 

 cost of repairs on an untreated barge 

 and its short life of real hard service 

 makes the annual cost, including inter- 

 est, 25 per cent more than for the pres- 

 sure creosoted barge. That the pressure 

 creosoted yellow pine barge and the 

 pressure creosoted Douglas fir barge 

 have respective fields depending upon 

 the working conditions; on the Lower 

 ^Mississippi, where there is always a 

 good stage of water, the creosoted 

 yellow pine will probably be more de- 

 sirable, but for light draft and use on 

 the upper Mississippi the pressure creo- 

 soted fir will be far more economical. 



*By courtesy of the American Wood Pre- 

 servers Association. 



UNTREATKD DOUGLAS FIR HULL FOUR YEARS OLD. 



PLANTING NEW PINE TREES 



Superintendent Eldridge, of the zvestern division of the Florida Forest Reserve, is shozc- 

 ing great activity and is securing good results. He will plant this season 800 pounds of 

 Maritine pine seeds, a French species of the pine zchich the government thinks zinlj serz'e 

 as zvell for naval stores purposes as the Southern pitch pine. The start with this pine ivas 

 made last year by planting 500 pounds of seed. 



