| 摘要 |
<p>Vessel including a hull of a substantially closed surface has at deck level a lifting crane, ballast tanks within the hull and a ballast control unit for admitting water to the ballast tanks for changing the draft of the vessel. The hull has a narrow lower section having first width over a height from keel level to a widening level, and a top section having a larger width than the lower section, extending from the widening level upwards towards deck level. The control unit is adapted to ballast the vessel to have a relatively shallow draft level in a transit mode, so that the wide top section is above water level, while the vessel is traveling, and to ballast the vessel to a relatively deep draft level in a lifting mode so that the widening level is below water level, at least when the vessel is substantially stationary and the crane is in its lifting position.</p> |
