PURINGTON.] 
DREDGttfGL 
187 
dredge, with consequent disturbance of the grades of the gold-saving 
devices. Hulls are now generally made with overhanging houses, 
which give more deck room and permit of the location on board of a 
small though very convenient shop. The crowning of decks has 
resulted in cleaner and drier dredges. 
Stronger gauntrees have been introduced in the late installations. 
The bow gauntree, at first considered merely as a support for the out- 
board end of the digging ladder, is made much heavier, as it is now 
designed also to tie together the bow pontoons. 
The main gauntree, on which are sustained the upper tumbler and 
its driving gear and the inboard end of the digging ladder, is made 
much stronger than formerly, particularly when the upper tumbler has 
a gear drive and a good alignment becomes therefore essential. In 
Fig. 39.— Sketch showing danger of grounding boat in tailings when pivotal points are too close 
together. 
dredges recently constructed the main gauntree has been made the ver- 
tical post in longitudinal and transverse trusses which tend to prevent 
the distortion of the hull, due to the great weights of the digging and 
tailing machinery, which are sustained respectively at extreme bow 
and extreme stern. Stern gauntrees have not been much modi tied, 
but have been strengthened and made somewhat higher, so as to sustain 
longer stackers. 
The introduction of some form of derrick or crane, at the bow, 
to move stumps and other obstructions and to hoist machinery, is 
now common. The use of traveling cranes over driving and other 
machinery is not so general as it should be, for such devices save time 
and labor when, as is frequently the case, renewals or repairs are 
necessary. The machinery is now generally housed. 
