DIFFERENT TYPES OF PROTECTION STRUCTURES:,

Spool protection covers:

We have covered thousands of meters of spools in the North Sea.

Flexibility - From the point where we get a sketch of the spool to be protected, to the actual cover is designed for construction, many of the parameters can (and will) change. In cooperation with our customers we have designed special types of covers to secure an optimal flexibility with regard to installation.

Stacking - More and more the installation companies are focusing on decreasing the amount of operations. In this respect we are contributing by delivering stacks of covers to rationalize the installation.

Skirne/Byggve 2003

Vigdis Extension 2003 Back to top >>

Template, Plem, Tee, protection covers:

We started our production of subsea protection covers in 1992 with 4 template protection covers for Draugen (see below).

Accessibility:

• Accessibility is always an issue when protection subsea installations. Giving the ROV the needed access has become increasingly demanded.

ROV operated hatches

• The use of buoyancy foam as a core material in the GRP/FRP gives the user the desired buoyancy at any dept.
• Perforated hatches to decrease added mass are also widely used.

Draugen 1992/93

Mikkel 2003

Mikkel 2003 Back to top >>

Open dropt object protection structures:

The past few years we have been working on open-design structures to help with splash-zone problematic as well as increasing access for the ROV. These are only protecting the subsea equipment from dropt object and are not over-trawl able

These kind of structures are somewhat more expensive on delivery (ex works), but are cost saving both in regard to installation-time and inspection-time (full ROV access).

Grane/Heimdal 2003

Grane/Heimdal 2003 Back to top >>

Alternative structures

In some situations we are faced with criteria that require hybrid solutions. For example if we are working with protection structures in shallow water, this requires more weight to compensate for waves and current.
We have also used sandwich constructions (GRP/FRP and buoyancy foam) to create shock-absorbing structures.

Ringhorne Jurrasic 2003

Nam Con Son, Vietnam 2001

Ringhorne 2001

Heimdal 1999 Back to top >>

Typical issues we deal with in the early stages of a project:

• The radius of the spool, not yet determined
• Installation period, winter
• Your vessel is not yet decided
• The need for stacking due to possible lack of deck space
• The need for 100% ROV access
• Over-trawl able and 100 KgJ dropt impact
• Dept 100 meters
• Rock dumping 3 months after installation, possibly in the winter period

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