420 LOGGING 
There are a variety of forms in which rafts are built, depending 
upon the character of the water on which they are to be towed, 
the kind of timber rafted and on the Federal regulations^ gov- 
erning rafting. 
Bag or Sack Booms. — These are used on the Great Lakes and 
on large rivers. They have a single or double row of boom 
sticks surrounding the impounded logs. For lake work short 
boom sticks of large size are preferable because loose logs are 
less apt to slip under them than they are under the long ones. 
Fig. 150. — Method of fastening Rafting Poles to Logs by means 
of Iron Dogs. 
On the Great Lakes double booms with connecting chains made 
of Ij-inch iron are considered superior to single booms, especially 
for rough water. A type of boom which is serviceable for im- 
pounding logs for towing in bad weather is made from white 
pine logs 24 inches or more in diameter and from 16 to 24 feet 
in length. The boom sticks are bored 18 inches from the ends 
for 1|- or Ij- inch chains and are blocked across the top 
and bottom, in front of the chain holes, with hardwobd strips 
to prevent the chains from cutting into the boom sticks. The 
chains should not be longer than is necessary to permit the ends 
of the boom sticks being coupled 24 inches apart. Two sets 
of boom sticks are placed around each raft so that it will not go 
to pieces if one set of chains is broken. During the period when 
the exportation of logs was permitted by the Provincial Govern- 
ments of Canada, large quantities of white pine were rafted to this 
country and manufactured at points along the Great Lakes. The 
season for towing was from June 1 to October 15. The rafts 
contained from 2,000,000 to 6,000,000 board feet each, and were 
handled by powerful tugs The transport of logs from Canada 
1 The Federal government specifies the form, size and character of rafts that 
may traverse certain navigable waters and harbors. 
