seawater 
4— hydraulic powcr supply 
irolne mote ini ee a 
hydraulic propulsor 
a ey, 
——— (Pe Oe I SS OE Z 
work barge 
soft bottom 
Figure 46. Concept of a barge-mounted work system for local excavation. 
Summary 
Adequate pressure-resistant buoyancy systems are available, but 
costs for depths to 20,000 feet are inordinately high, suggesting investigation 
of new approaches such as beneficiated wood. 
Future Plans 
No active research and development are planned in the area of 
buoyancy, except for limited, informal small-scale pressure chamber trials 
of a few simple systems for impregnating and sheathing wood. 
SHALLOW DRILLING AND EXCAVATING 
The operations described in this section are those which in surface 
operations normally would be done by bulldozing, scarifying, scraping, shallow 
auger drilling, and loading and removal of the spoil from the site, or using it 
for backfill. These are all specific operations requiring great operator skill and, 
to achieve accuracy, repeated checking of grade, tamping, etc. There is at pre- 
sent no reasonable hope of performing these same functions on the ocean 
bottom in the same manner. Fortunately, there appears to be no need to use 
established terrestrial methods. 
58 
