Cleaning boats

Keeping your boat and related equipment clean helps stop the spread of aquatic pests around our coastline, and between our rivers and lakes. In some cases, it can even save you money.


Why clean?

If you have a boat, it's important to keep it clean – especially when you change location. If you don't, you could be spreading pests between New Zealand's lakes and rivers or around our coastline. Aquatic pests can affect:

  • aquatic habitats (including fish and shellfish habitats)
  • activities such as fishing, swimming, sailing and diving
  • aquaculture.

Regular cleaning also:

  • makes your boat and gear last longer
  • reduces vessel running costs because you'll use less fuel
  • reduces maintenance costs.

How to clean trailer boats

Before moving your boat to a new coastal area, lake or river:

  • wash the boat and trailer with fresh water if it has been in salt water, or a detergent solution if it has been in fresh water
  • remove fouling (like weeds, crabs, and barnacles) and dispose of appropriately on land – make sure to check the propeller, anchor well, anchor and chain
  • drain or thoroughly rinse areas where water pools
  • allow to air dry for several days before using it in the new location.

Check, clean and dry any equipment on your boat including mooring lines and buoys.

How to clean moored boats

Any boat that is moored in sea water (including yachts, launches, fishing boats and barges) can collect marine pests in the growth (biofouling) that builds up on the vessel bottom.
Before leaving for another part of New Zealand, check your boat for biofouling and clean it if necessary. If you're going for a while, we also recommend you reapply antifouling before you leave.

If you use antifouling paint on your hull, you should replace it:

  • once a year or as often as the paint manufacturer recommends
  • if the paint has been damaged
  • if your boat is getting a lot of fouling.

How to clean your boat hull

If you own a moored boat, the hull should never have more than a slime layer. We recommend you regularly brush or wipe off the hull – without damaging the antifouling. You should also regularly clean your boat out of water and reapply antifouling paint.

New Zealand's Clean Boating Programme has instructions for cleaning moored boats in their Clean boating guide.

Pay particular attention to:

  • the hull, keels and stabilisers
  • intakes and outlets
  • propellers and shafts
  • rudders, rudder shafts and casings, rudder recesses
  • anchors, anchor chains and anchor wells.
Side view of 2 boats showing areas to clean
Areas to clean on your boat

How to apply antifouling

Use an antifouling paint that's suitable for your boat type and its use.

For best results, clean, sand and prime the hull before you apply 2 or more good coats of antifouling paint. Let the antifouling dry completely between coats and, ideally, leave your boat out of water for 24 hours after the last coat.

Where to clean your boat hull

Most New Zealand marinas have haul out facilities and hardstands. Contact the marina to find out about their cleaning facilities.

Find out more

Who to contact

If you have questions about cleaning boats, email info@mpi.govt.nz

If you think you've found a marine or freshwater pest, call our pest-and-disease hotline on 0800 80 99 66.

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