Marine and Ocean Engineering Systems 
Marine and ocean engineering systems include surface platforms, 
positioning systems, operations monitoring systems, and lifting/lowering 
systems. 
Surface Platforms. Ocean platforms, such as drill ships, work 
boats and barges, are suitable for the concrete placement operation. A 
drill ship is probably the best suited vessel for the task because it 
already has the necessary marine operations systems, most of the ocean 
engineering systems, and the pipe and pipe handling systems, all in 
place and functioning in a demonstrated manner by crews experienced in 
working together. Drill ships typically have some oil well cementing 
capability but this is too limited for our purposes. The main items to 
be added to the drill ship are the materials, the materials storage and 
handling equipment, the concreting equipment, and the concreting personnel. 
For a small operation using a small drill ship such as a deep ocean 
coring ship, the concreting equipment and materials would be placed on a 
barge alongside the drill ship. Concrete would be pumped from the barge 
to the drill ship and then (by a second pump on the drill ship) down the 
pipeline. A small drill ship suitable for placing several hundreds of 
cubic yards of concrete to 5,000 ft or greater depths may be leased for 
about $7,000 per day including marine and drilling crews working a 
24-hour day, and a barge for $2,000 per day. 
On a large job using a large drill ship there would be space on 
board for the concreting equipment and some materials storage. A barge 
alongside would provide major materials storage. A shuttle barge would 
resupply materials as needed. Representative costs are $30,000/day for 
a drill ship, $2,000/day for a barge, and $5,000/day for a tugboat and 
shuttle barge combination. 
Many drill ships that can moor in 600-foot water depths are located 
around the world. Also some drill ships can moor in water depths to 
2,000 feet; the number of these vessels is increasing all the time. 
Only a few drill ships can keep station in deep water. Thus a major 
limiting factor in adapting drill ships for deep ocean concreting is the 
station-keeping capability in deep water of available vessels. For 
depths less than 2,000 feet or so, most drill ships are outfitted to 
moor with anchors. Some drill ships are equipped with dynamic positioning 
systems for operating in depths to 3,000 feet, but could maintain station 
in much deeper water. Dynamic positioning systems are typically sophis- 
ticated and expensive although less expensive systems exist. For example, 
a small seafloor coring ship, the CALDRILL, works to 6,000-ft water 
depths using four Harbormasters manually controlled to position the ship 
relative to a taut wire reference. 
Another approach is to use an ocean-going workboat such as NAVFAC's 
SEACON. This ocean construction barge has established marine operations 
systems, including dynamic positioning, and ocean engineering systems, 
as well as a center well and considerable deck space. Pipe and a handling 
system, such as a portable oil well rig would be added as would the 
concreting equipment. 
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