Trans RINA, Vol 153, Part A1, Intl J Maritime Eng, Jan-Mar 2011
Class: Note:
Cost: Figure 12: Lancelot Accommodation Work Barge
Technical features Length: Beam:
Draught: Capacity:
111.56 m 31.7 m 4.50 m
300 men in single, double and four men cabins. Single berth: 8 x 1 berth; Double berth: 14 x 2 berth Four (4) men berth: 66 x 4 berth
Class: Cost:
ABS A1 Accommodation Work Barge
US$36 million 5.3 SELF-PROPELLED MONO-HULL BARGE
These vessels incorporate a propulsion system that is normally used for station keeping; therefore, it is more a DP system than
a pure propulsion system for
navigation. In this way, the barge can be used in unlimited depth waters, more than 300 m depth, the practical limit for moored barges.
5.3 (a) SAFECOM 1 This
Accommodation Field Development Vessel
(AFDV), owned by B-H Offshore, is very similar to the previous example, AWB Lancelot: also having an 8 Point Mooring system, all the accommodation facilities for offshore workers and a big lifting capacity. But apart from that, it has also some features typical of flotel
ships: offshore gangway and a DP system consisting on 6 thrusters. 6. 6.1
ABS A1 Accommodation Work Barge DP2
Complies with latest editions of SOLAS & MARPOL; SPS & MODU code stability compliant. -
SEMI-SUBMERSIBLE ACCOMMODATION BARGES
A semi-submersible vessel
INTRODUCTION barge
with good
is a specialized marine stability and seakeeping
characteristics. The semi-submersible type of vessel is commonly used in a number of specific offshore roles such as for offshore drilling rigs, safety vessels, oil production platforms, heavy lift cranes and also as accommodation vessels. The terms “semisubmersible”, “semi-sub” or just “semi” are also generally used for this type of vessel. Semi-submersibles are particularly well-suited to a number of offshore support vessel roles because of their good stability, large deck areas, and variable deck load (VDL).
In areas such as the northern North Sea,
semisubmersibles are largely used for drilling construction and for floating production because of their ability to carry out their operations over extended periods without interruption due to weather downtime. This is possible due to the better performance in heave and righting moments with little effect of the waves on the barge motion. This lack of response to the typical wind-driven seas is due both to the relatively small change in gross buoyancy and to the much longer natural period of the vessel, especially in roll, pitch, and heave. Whereas the standard mono-hull barge has a natural period of 5-6 seconds,
the typical
semisubmersible barge has a natural period of 17-22 seconds. Nevertheless, there are three penalties to pay for this favourable performance:
Semi-submersibles have much greater response to externally applied loads such as weights, loads, and ballast. Another way of stating this is to say that its righting moment and metacentric height are much lower than those of a standard mono-hull barge
o Figure 13: SAFECOM 1 - AFDV
Technical features Length: Beam:
Draught Capacity:
100.58 m 31.70 m 4.50 m
400 beds in total: 1, 2 & 4 bed cabins. Total of 140 en suite cabins.
the stability performance is worse than a mono-hull
barge, and it is modules as in a mono-hull barge.
The semi-submersible has seriously reduced topside cargo capacity. It relies on a low centre of gravity to maintain stability
o This is related to the previous point and confirms that the mono-hull barges offer more
capacity for installing living quarters. therefore
impossible install as much in the way of living
quarters or accommodation
©2011: The Royal Institution of Naval Architects
A-49
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