Section 4 Foundation Structure Survey & Approval

4.1.1 The full process to be implemented for the Foundation Structure Survey & Approval is given in Figure 4.4. The relevant Sections are also highlighted.

4.2.1 A risk assessment has to be conducted during the initial design stage for the whole rotor installation and therefore a separate risk assessment study may not be needed for the foundation structure. In situations where the initial risk assessment does not include consideration of the foundation structure of the rotor, a new risk assessment must be conducted.

4.3.1 Structural Appraisal

1. Required Submissions

   • Scoping study report (Stage 1 ARBD process)
   • Risk Assessment report (Stage 2 ARBD process)
   • General Arrangement (GA) of Flettner rotors on the vessel
   • The details of foundations for Flettner rotors
   • The details of exact position of each Flettner rotor foundation and its integration with the deck
   • Welding details
   • Drawings of the local deck structure on which the foundation is to be mounted
   • All forces generated by the Flettner rotors in operation
   • All forces due to ship motions based on the weight and position of the Flettner rotors
   • Information related to any limitations of the vessel (service restrictions, stability or other)
   • Information related to any limitations of the use of the Flettner rotors (wind speed, wave height or sea state)

2. Applicable Rules (Existing)
   Provisional Rules for Sail-Assisted Ships, January 2008

   • Ch 1, 1.4 Structural arrangements

   Rules and Regulations for the Classification of Ships

   • Pt 4, Ch 1, 4 Deck structure
   • Pt 3, Ch 9, 6 Lifting appliances and support arrangements

   LR Code for Lifting Appliances in a Marine Environment (LAME) (2013)

   • Ch 4, 2.11 Forces due to ship motion
   • Ch 4, 5.3 Allowable stresses
   • Ch 4, 5.2 Design loads

   ShipRight procedure for ARBD

3. Additional Verification
   For the worst loading condition, the structural strength at points integrating the Flettner rotors with the deck structure will have to be evaluated to ensure sufficient under deck stiffening and plate thickness to withstand the bending moments generated.
   Depending on the design of the Flettner rotor foundation and the way it is attached to the deck, direct calculations and FEA calculations will also be necessary.
   During plan approval all aspects of the strength will be assessed and, if necessary, additional strengthening will be required.
   The risk assessment should be completed before commencement of the structural appraisal of the installation.

4. Deliverables
   The DAD will be issued at the end of the design approval process.

4.4.1  Survey & Inspection. The survey and inspection of the rotor foundation structure during its construction are to ensure that the relevant Rule requirements stated in this guidance have been complied with and any conditions given in DAD are addressed. It has to be conducted in accordance with Ch 1, 1.6 Survey requirements for sail systems of Provisional Rules for Sail-Assisted Ships, January 2008 and LAME (2013), Chapter 12, Ch 12, 3 Survey requirements as applicable.