SUB-BUNG-OWF-T™ Topside Grouting Bungs are utilsed during the transition piece (TP) to monopile (MP) grouting operations. The annular gap between the two structures is bottom filled injected with a grouting mixture. To ensure the grouting mixture level fills to the top of the annular gap, air must be vented to prevent a grouting airlock. SUB-BUNG-OWF-T™ Topside Grouting Bungs comprise a snorkel guided vertically into the hollow air-pocket. Once the bung is activated and sealing either 03-off or 04-off, 60 mm diameter holes, the grout mixture level shall fill to the top of the annular gap ensuring grouting joint integrity.