Work vessels

If you're bringing a work vessel into New Zealand, you need to meet certain rules around biofouling. Find out the requirements and how to meet them.

What are work vessels?

Work vessels are generally vessels that move at a slow pace and are likely to be stationary for periods of time. 
They include:

  • tugs
  • barges
  • dredges
  • defence vessels
  • military ships
  • heavy lift vessels.

What you must do

If you're the operator of a work vessel coming to New Zealand, to meet our biofouling rules you need to:

To demonstrate best practice, we recommend you create and follow a biofouling management plan and record your maintenance activities in a log book.

If your vessel has been stationary for periods of time, it probably requires cleaning before arrival in New Zealand. Evidence of cleaning needs to be kept and may be requested by a quarantine inspector on arrival.

Requirements depend on time in New Zealand

Most work vessels fall under MPI’s 'long-stay' category (plan to be in New Zealand for 21 days or more or visiting places that aren't places of first arrival).

  • Long-stay vessels are only allowed a slime layer and gooseneck barnacles.
  • Short-stay vessels (20 days or less) are allowed slightly more biofouling.

Allowable amounts of biofouling are set out in the biofouling craft risk management standard.

Download the craft risk management standard for biofouling [PDF, 241 KB]

Download the guidance document for the CRMS [PDF, 1.5 MB]

Download the craft risk management standard - frequently asked questions [PDF, 1.8 MB]

Photos to help you assess biofouling

Clean before you leave

Operators of vessels that are more likely to be fouled must provide MPI with evidence, before they arrive, that the vessel will be clean.

You'll need to arrange a biofouling inspection by an appropriately qualified provider and provide the evidence to MPI before leaving for New Zealand. Evidence may include provider recommendations and evidence of cleaning or treatment of the hull and niche areas.

You may get the vessel cleaned or treated in New Zealand within 24 hours of arrival if you can provide proof with your arrival documents of a facility booking.

Cleaning means the removal of all biofouling (other than a slime layer and gooseneck barnacles) from all hull and niche areas.

Continual maintenance of work vessels

Continual maintenance involves ongoing management of biofouling, including:

  • having a biofouling management plan specific to the vessel
  • coating the hull and niche areas with antifouling paint appropriate to the operating profile of the vessel
  • regularly inspecting and cleaning the hull and niche areas
  • keeping records to show how biofouling is managed
  • having contingency plans in place to minimise fouling if the vessel falls out of its operational  profile.

Most work vessels will require cleaning following periods of being stationary in addition to continual maintenance.

Use suitable hull antifouling systems

The vessel hull should be painted with an antifouling system that can prevent biofouling between dockings.  The system applied should take into account:

  • the planned docking period
  • the ship’s speed and activity
  • any periods that the vessel will be stationary.

Where antifouling paint is damaged, consider in-water repair of the paint in the area, even if minor. 

Maintain, inspect and clean niche areas

Sea chests

  • Paint internal surfaces with antifouling paints suitable for the flow of seawater.
  • Use marine growth prevention systems (MGPS), such as chemical dosing systems, where possible.
  • Regularly use steam blow-out pipes if fitted in sea chests to reduce biofouling growth.

Sea inlet pipes and outlets

Apply antifouling paint inside pipe openings and pipework. Antifouling paint adheres and lasts longer if:

  • all sea inlet pipes and outlets are rounded
  • grates on seawater intakes are made with round bars.

Hull appendages as niches

Any hull appendages can act as niche areas, even when painted with effective antifouling. You may need to include them in a maintenance programme.  Hull appendages include:

  • dry docking support strips
  • bow and stern thrusters
  • bilge keels, cooling scoops and propulsion scoops
  • rudder hinges and stabiliser fin apertures.

Hull appendages that can't be painted with antifouling paint – because it affects their operation – may need additional maintenence and cleaning. These include:

  • anodes
  • velocity probes
  • echo sounders.

Internal seawater systems

Effective marine growth protection systems (MGPS) can be fitted to internal seawater systems prone to biofouling.  Use these systems regularly and monitor them to make sure they're working well. If MGPS haven't been fitted or haven't prevented biofouling, treat internal systems before arriving in New Zealand.

Find out more

Who to contact

If you have questions about biofouling requirements for work vessels, email 

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