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Anchoring methods for DIFIS project

Anchoring methods for DIFIS project. Anchoring methods for DIFIS project. Factors must be taken in account: soil nature, depth of water, weather conditions, the type and weight of mooring lines, the need of retrieval, and the cost of installation/retrieval.

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Anchoring methods for DIFIS project

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  1. Anchoring methods for DIFIS project JF Drogou ; JP Lévêque

  2. Anchoring methods for DIFIS project • Factors must be taken in account: • soil nature, • depth of water, • weather conditions, • the type and weight of mooring lines, • the need of retrieval, • and the cost of installation/retrieval JF Drogou ; JP Lévêque

  3. Anchoring methods for DIFIS project • Soil nature classification all around the coasts: • Soft clay • Firm clay • Stiff clay • Hard clay • Hard soil • Soft rock • Intact rock • Measurement of soil characteristics: • Sediment echo sounder systems, with ship or ROV • Drilling or coring systems (specific tools deployed from the ship) JF Drogou ; JP Lévêque

  4. Anchoring methods for DIFIS project • The depth of the sea in relationship with the locations of disasters: Depth >1500m - 90% of the area is made of clay and soft sand JF Drogou ; JP Lévêque

  5. Anchoring methods for DIFIS project • Weather conditions • WOROV operational limitations: • Wind: 25 knots • State of sea: • swell 3m • surface current: 2 knots • Subsea current: 2/3 knots JF Drogou ; JP Lévêque

  6. Anchoring methods for DIFIS project • Recommendations: • Characteristics of the soil must be perfectly known • Mooring lines and anchor model must be chosen in relationship with a anchor builder: JF Drogou ; JP Lévêque

  7. Anchoring methods for DIFIS project • Type and weight of mooring lines: Taut legs mooring system Vertical or adjustable angle efforts on the anchor Catenary mooring system Horizontal efforts on the anchor JF Drogou ; JP Lévêque

  8. Anchoring methods for DIFIS project • Tree anchor models can be used: Drag embedded anchor VLA anchor Suction anchor JF Drogou ; JP Lévêque

  9. Anchoring methods for DIFIS project • Choice of anchor model in relationship with the type/weight of mooring lines: • Taut legs mooring system: • - Vertical Load Anchors (VLA) - Suction Anchors Catenary mooring system: - Drag embedded Anchors JF Drogou ; JP Lévêque

  10. Anchoring methods for DIFIS project • Choice of anchor model in relationship with the nature of the soil, storage on board and retrieving possibility JF Drogou ; JP Lévêque

  11. Anchoring methods for DIFIS project • Choice of anchoring methods in special cases: • Soil is rocky: • Mechanical fitting directly on the hull by pyrotechnic, drilling or magnetic devices • In lower depth water and soft soil: • Driven pile anchors can replace suction anchor • Driven anchor plates used as suction anchor but the fitting is made by vibration jetting or impacting into the place • Torpedo embedded anchor used as suction anchor but the fitting is made by kinetic energy JF Drogou ; JP Lévêque

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