The existing piles have also been replaced.
The upgrade is part of routine maintenance at the district council-owned facility which employs Mr Caulton as manager through the Whangarei Marina Management Trust.
The trust is also looking to meet a growing demand for boating facilities and has progressed plans for more berths downstream from Te Matau O Pohe bridge near Limeburners Creek on the west bank.
The marina has hit full capacity in recent years during peak times.
The trust is preparing a resource consent application and the main consideration is to consult with iwi.
"We are very mindful of any cultural considerations," Mr Coulton said.
If the application is successful, and the business case for the expansion stacks up, Mr Coulton hopes to see about 100 new berths established by October 2019.