1.1
Diving systems audit
Saturation and surface-supplied systems, audited for compliance against IMCA D023, D024, D037, D040 and D053. Pre-mobilisation verification, gap analysis, and a report to operator and contractor management.
We have runspreads likethe oneswe audit.
Diving and ROV systems audit, technical inspection and client site representation. North Sea to Asia, saturation to offshore wind.
Placeholder photo: US Navy, public domain
30+Years offshore
1991In the field since
11Named operators and contractors
6IMCA documents audited to
Worked with RWE · TenneT · Jan De Nul / Vineyard Wind · QatarEnergy
1.0
Four disciplines, each to its own standard.
From the pre-mobilisation audit to oversight on the worksite, to IMCA, IOGP and client requirements.
1.2
ROV systems audit
Design and operational audits of ROV systems and tooling to IMCA R006: control systems, hydraulics, tooling interfaces and readiness before deployment.
Oil, gas,
renewables,
civil.
renewables,
civil.
1.3
Subsea consultancy
Oil, gas, renewables and civil. Scope, methodology review, risk assessment and execution support, from mobilisation to close-out.
1.4
Personnel and CSR
Diving and ROV personnel, provided and assessed. Client Site Representatives who keep the operator's eyes on compliance, safety and quality at the worksite.
2.0
What are you mobilising?
Pick the system. The answer shows the standard or service it falls under, the certificate we hold, and where we have done it before.
Standard or service
Certificate held
What we do
Relevant experience
IMCA titles as listed in the IMCA Guidance Register, June 2026.
3.0
Certified as individuals, not as a logo.
Our auditors hold individual certification for systems design audits and client site representation, worldwide.
| Body | Scope | Certificate no. |
|---|---|---|
| IOGP | Client Site RepresentativesOperator oversight of diving and ROV operations on offshore installations and vessels. | CR/2021/018 |
| IMCA | Diving Systems Design AuditorsDesign and compliance audits of saturation and surface-supplied diving systems. | DRSAAA/2021/020 DSAA/2014/098 |
| IMCA | ROV Systems Design AuditorsDesign and operational audits of ROV systems and tooling packages. | DRSAAA/2021/020 RSAA/2016/006 |
4.0
Three co-owners, on the job.
A specialist practice. Each engagement is led by a co-owner with direct operational authority and individual IMCA or IOGP certification.
4.1
Bart Tonckens
CSR / Auditor & Co-owner
Over thirty years offshore, from saturation bell diving to IMCA and IOGP systems audit. He has supervised diving and ROV operations and acted as Client Site Representative for operators across the North Sea, the Middle East, Southeast Asia and US offshore wind. Now Diving Manager and CSR with QatarEnergy, he leads BT Subsea's audit and inspection practice. Certified in Part II Bell Diving and as a diving medic; IOSH.
4.2
Glenn Johnston
CSR / Audit Project Manager & Co-owner
IOGP-registered Client Site Representative. Glenn runs project delivery and the audit programme, from scope definition to executive reporting. His background: diving supervision, project management and quality assurance in oil and gas, renewables and civil marine construction.
4.3
Mick Tuddenham
CSR / Auditor & Co-owner
Known in the industry as Tuddy. An IMCA-certified auditor known for thoroughness, with hands-on time on diving spreads and ROV campaigns on several continents. His field experience turns audit findings into operational improvements.
5.0
Three decades offshore.
Our audits are written by people who have run the spreads they assess.
- 2025 - presentQatarEnergyDiving Manager and Client Site RepresentativeDoha, Qatar
- 2025Dominion EnergyClient Site Representative, offshore substation installationsOffshore Virginia, USA
- 2024 - 25RWE offshore windDiving and ROV CSR across Amrumbank, Arkona, Nordsee Ost, Kaskasi, Borkum and MerkurNorth Sea and Baltic
- 2023 - 24Jan De Nul, Vineyard WindCSR for HV cable pull-ins, terminations and testingOffshore Massachusetts, USA
- 2022 - 25TenneT OffshoreCSR for WTG, HV cables and UXO, including Hollandse Kust Zuid Alpha and BetaNorth Sea, Netherlands
- 2023Vattenfall · EnecoCSR on WindplanBlauw and Luchterduinen wind farmsNetherlands
- 2021 - 22IOECAuditor to IMCA D023, D024, D037, D040, D053 and R006
- 2002 - 18Mermaid and Kreuz SubseaDiving supervisor and bell divingSoutheast Asia: Thailand, Singapore, Indonesia, Malaysia and more
- 1994 - 2002N-Sea (formerly Noordhoek Diving)Diving supervisor, bell and air divingNorth Sea and worldwide
Operators and contractors worked with includeQatarEnergy, Dominion Energy, RWE, TenneT, Vattenfall, Eneco, Jan De Nul, PETRONAS, GUPCO, Sapura Energy, Ballast Nedam and more.
6.0One saturation system,
One saturation system,
every section.
A DESIGN audit checks the system line by line against the detail sheets of IMCA D024, DESIGN for saturation (bell) diving systems (Rev. 4, June 2026). Scroll to follow it through all fifteen sections.
Every section, checked before the system mobilises. Then the report.
Schematic is illustrative: a moonpool-launched system on a dive support vessel. Section titles from IMCA D024.
7.0 · Request an audit
Scope it in
a minute.
Pre-mobilisation audit, ongoing CSR support or specialist consultancy: tell us what and where, and we will come back to you.
bart@btsubsea.com
contact@btsubsea.com
+974 5507 0263
