A Towhead is a structure that is pre-fabricated onshore and is found at either end or in the middle of a pipeline Bundle and allows that bundle to be towed to site. The smallest are approximately 8 metres in length and 3 metres high, weighing approximately 100 tonnes. The largest are approximately 40 metres in length and 8 metres high, weighing over 500 tonnes.

A subsea valve is a device which either isolates or regulates the flow of material. They are most commonly integrated into manifolds, but are occasionally found as stand-alone structures. Stand-alone subsea valves are most commonly found towards the ends of pipelines or close to pipeline junctions. Typical valves will be 1 metre wide and 1 to 2 metres high, although larger Isolation Valves may be 8 metres wide and up to 5 metres high.

There are many reasons a surface buoy may be on location, such as met-ocean, structure marker or anchor buoys. They are generally in place to provide a warning of potential danger and should be equipped with lighting, high visibility colour and radar reflectors. Any buoy will be anchored to the seafloor through use of chain, anchor, or they may be attached to a structure.