positioning the solitaire
TRANSCRIPT
Positioning Solitaire From surface to seabed
By Marco Kwanten
Hydrographic Society Benelux Wednesday, 14 October 15
Allseas fleet
SolitaireSolitaire AudaciaAudacia LorelayLorelay
Tog Tog MorMor Calamity JaneCalamity Jane Pioneering Spirit
Solitaire specification
Length (incl. stinger)
:Length (excl. stinger)
:
Breadth
:Stinger length
:
Minimum radius
:Installed power
:
Maximum speed :
Tension capacity :
Pipe diameters
: Pipe storage
:
Multi-purpose crane
:Accommodation
:
(1302 ft)(984 ft)(135 ft)(459 ft)(394 ft)
(69,063 hp)
(2315 kips)
(661 kips)
397 m300 m41 m
140 m120 m
51,500 kW13.5 knots
1050 t2”
to 60’’
22,000 t300 t
420 persons
Tasked to lay pipe from A to B
Main mast and gantry mast
Two sets of 2x GNSS receivers with:•
2x L-band corrections (each)•
1x GNSS antenna (each)•
Input from one of the 2 Inmarsat
domes•
QC computer•
NTRIP corrections (Network Transport of RTCM data over IP)
During unguided lay, heading is very important. With a layback of 600 m in shallow waters, 0.4°
heading difference (Octans
precision of 0.1°
seclat
at 1σ
translated to 60°N at 2σ) amounts to a 4.2 m difference on the seabed.
In deeper waters the layback may increase to several kilometres,
but next to heading, the current starts playing a role. Corridors are usually wider in deeper waters.
Heading
• PPP heading shows 0.1°
difference, roll induced as height difference between antennas is 15 m
• LD7 heading is noisier that Octans
heading• PPP heading is noisier than LD7 heading• Octans
units do not seem to drift >0.05°
from LD7
On pipeline heading
• PPP heading shows -0.2°
difference, roll induced as height difference between antennas is 15 m
• LD7 heading is noisier that Octans
heading• PPP heading is noisier than LD7• All 3 Octans
units have different drift, but well within their specs within this period
In a curve
Layback is calculated from the bead stall to touchdown and is dependent on lay vessel tension:•Pipe parameters (wall thickness, coating, steel grade etc.)•Stinger settings (radius, departure angle)•Client/DNV criteria•Depth•Dynamics (shifting TD point)
Varies from ~400 m to 3500 m
Layback