Riser Clamp Installation (Air Diving Range)

This is an excellent high quality video showing Air Diver performing underwater clamp installation. The waterdepth is about 14 m ( 46 ft). I believe the video was taken using[abbr title=”Remotely Operated Vehicle”]ROV[/abbr]. (ROV umbilical – 03:08). It is possible to perform double operation Diving & ROV as long as in accordance with all the safety requirement. I’ll share these requirement in future post.

From the video we can observe the following:[unordered_list style=”bullet”]

Newly installed riser clamp ( [abbr title=”Water Depth”]WD[/abbr] ~ 14m)
Subsea Riser Clamp No. 1 from [abbr title=”Mean Sea Level”]MSL [/abbr](Refer to the mark no. 1 on the riser clamp door)
Seen no anode on the clamp. Assumed there is a metal contact between horizontal jacket brace & riser clamp.
The bolt & nuts are impact tighten.
Messenger line to supply divers with all required tools & equipment.
Diving in tropical water. Diver wears denim diving suit.
The that i’m not sure is the yellow structure shown in 03:39

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What is Riser Clamp?

It is a Structure which is intended to keep the riser in place. There are various type, size and design of riser clamp.

Hanger Clamp (Load Bearing Clamp) : a clamp design to handle the vertical loading which capable to takes the weight of the entire riser + horizontal restraint. The clamp allowed the riser to slide axially.
Sliding or Guide Clamp : The clamp installed below after the load bearing clamp towards seabed. It provide horizontal restraint but again allow the riser to move/slide axially (typically 5mm anulus gap between riser & neoprene pad installed on internal surface of riser clamp shell.

The following document will be required during installation of riser clamps.

Client specifications / Contractual requirement.
Riser Clamps design & drawings – To ensure the right clamps installed at the right position.
Approved Riser Clamps installation procedure. Typically its a subsection of Riser Installation Procedure. The riser clamp installation procedure will become standalone if the installation is performed by different vessel which install the riser. Normally a small DPDSV or small barge. This approach is more economic if there is a lot of riser clamps need to be installed in a year programme/contract. In this case most of the time, the final tightening will also performed by this small DSV. The main work barge will only tighten the load bearing clamp.
Riser clamp installation Action List. This is a small field document but a very important piece of info. its a suit to site type of document but in line with all the above document. I’ll share sample of riser clamp action list in future post.
As built report (document/visual) signed/withness by client.

Ok Offshoreman, need to stop here. been a long time i’m not writing. Please come back or comment this post. I might miss an important notes. Or maybe someone expert from subsea division may add notes to this post … Spasiva!