0027/nd guidelines for Marine Lifting and Lowering Operations

16.3 
CLEARANCES AROUND LIFTED OBJECT (JACKED-UP CRANE) 
16.3.1 
The clearances in Section 16.2 above may be reduced to 1 metre for lifts to and from the jack-up deck 
(when elevated) and fixed structures provided that either suitable bumpers and guides or a very 
reliable manoeuvring system using tuggers or similar and an experienced crew are used. If bumpers 
and guides are used then the lifted object must be robust enough to withstand the likely loads from 
such aids without damage. 
11 
11 
11 

---

GUIDELINES
 
FOR
 
MARINE
 
LIFTING
 
&
 
LOWERING
 
OPERATIONS 
0027/ND Rev 11 
 
Page 58 of 84 
16.4 
CLEARANCES AROUND CRANE VESSEL 
16.4.1 
Where the crane vessel is moored adjacent to an existing fixed platform, the following clearances 
apply: 

5 metres between any part of the crane vessel/crane and the fixed platform or lifted structure for 
the mooring system intact condition; 

3 metres between any part of the crane vessel/crane and the fixed platform or lifted structure for 
the condition of the mooring system with the loss of one line; 

10 metres between any anchor line and a live “hot” platform for the mooring system intact; 

No contact between any anchor line and a live “hot” platform for the mooring system for the 
condition of the mooring system with the loss of one line;

5 metres between any anchor line and a shutdown “cold” platform for the mooring system intact; 

For the one line failure condition of the mooring system with the lifting vessel up against a 
shutdown “cold” platform, contact of the anchor line with the platform structure may be accepted 
on a case by case evaluation. 
16.4.2 
Where the crane vessel is dynamically positioned in accordance with DP Class 2 or 3, a 10 metres 
nominal clearance between any part of the crane vessel and the fixed platform shall be maintained.
This may be reduced in some cases to 5 metres as described in Section 13.6 of 0001/ND, Ref. [1]. 
16.4.3 
There should be a minimum under-keel clearance of 3 metres between crane vessel (including 
thrusters) and seabed, for an offshore lift after taking account of tidal conditions, vessel motions, 
increased draft and changes in heel or trim during the lift. Lesser clearance for operations in sheltered 
waters may be agreed with GL Noble Denton, depending on the seabed and environmental conditions, 
but should not be less than 1 metre. 
16.4.4 
Clearances around the crane vessel either moored or dynamically positioned and any floating platform, 
FPSO, drilling rig or submersible, shall be determined as special cases based on the station keeping 
analysis of the floating structure and the lifting vessel. Positioning equipment and procedures shall be 
defined to maintain the minimum clearances required for each specific operation. The procedures 
should minimise the durations for which these are required.