Pettit Neptune HRT Water-Based Bottom Paint

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Pettit Neptune HRT Water-Based Bottom Paint

Pettit Neptune HRT bottom paint uses the latest technology available to create a hybrid paint film strong enough to handle the tough marine environment without building up over time. Soap and water cleanup along with no strong solvent smell, yields a user-friendly application. Neptune HRT does not require sanding between coats saving time and money. With low VOC it's ideal for marinas under restrictions.

HRT: Hybrid Reactive Technology features high density biocide utilization to maximize effectiveness, along with film modifiers to reduce yearly build-up, maintain color consistency, and lower weight. 

  • Sold in gallons
  • Economical hybrid protection
  • Smooth durable polishing finish
  • Apply over most antifouling paints
  • Simple soap and water clean up

Colors Available: 1243 Blue, 1643 Red, 1843 Black


How To Apply Pettit Neptune HRT

Neptune HRT is easily applied by brush, roller or spray. When rolling use only a high-quality short nap (maximum 3/16” nap) roller cover. Apply using thin coats; over-application of this product will virtually assure inadequate coating performance. For the smoothest possible finish: Thin the paint approximately 5-10% with clean fresh water. Wet the surface to be painted thoroughly with clean fresh water as well. This will provide a truer color and smoother finish. Slight variations in color and surface texture are not uncommon and should not be looked at with dismay. The surface will quickly smooth itself once in the water and any mottling of the color will diminish as well.

Neptune HRT contains cuprous oxide. As a result, there is a tendency for settling to occur, especially if the paint has been n the shelf for several months. It is necessary to thoroughly mix the paint before using.

  • Finish: Flat
  • Application Method: Brush, roller, airless or conventional spray
  • Maximum Roller Thickness: 3/16”
  • Number of Coats: 1 minimum per season with additional coat at waterline
  • Wet Film Thickness: 3.75 mils
  • Dry Film Thickness: 1.5 mils
  • Application Temp: 50° F. Min. / 90°F. Max.
  • Thinner: Water
  • Coverage: 500 ft2 /gal

Previously Painted Surfaces:

  • To paint old hard and ablative antifoulings, thoroughly wipe down the surface with 120 brushing Thinner, paying particular attention to waterline areas, then sand painted surface with 80 grit sandpaper.
  • Wipe clean of sanding residue with water and apply Neptune HRT.
  • Old tin or copper copolymers or Teflon based antifoulings should be sanded thoroughly with 80 grit sandpaper to remove the chalky outer surface, wiped clean of sanding residue, and then may be over coated directly with Neptune HRT.
  • Soft, sloughing antifoulings should be removed before applying Neptune HRT.

Bare Fiberglass:

  • All bare fiberglass, regardless of age, should be thoroughly cleaned with 92 Bio-Blue Hull Surface Prep or de-waxed several times with Pettit D-95 Dewaxer.

Sanding Method: Sand the hull thoroughly with 80-grit sandpaper to a dull, frosty finish and rewash the sanded surface with 120 Brushing Thinner to remove sanding residue. Then apply two or three thin coats of this product, following application instructions. Careful observation of application instructions will help ensure long-term adhesion of this and subsequent years’ antifouling paint.

To eliminate the sanding method, three alternative methods are available:

  • Prep the surface with 92 Bio-Blue Hull Surface Prep or wash the fiberglass three times using Pettit D95 Dewaxer. Then apply one thin coat of Pettit 6998 Skip- Sand Primer. Use a 3/16” or less nap when applying by roller. Consult the primer label for complete application and antifouling top coating instructions. Apply two or three thin coats of this product.
  • Thoroughly clean, de-wax and etch the surface with 92 Bio-Blue Hull Surface Prep using a course Scotch-Brite pad in a swirling motion. Thoroughly rinse all residue from surface and let dry. Then apply one coat of Pettit-Protect High Build Epoxy Primer. Consult the primer label for complete application and antifouling top coating instructions. Apply two or three thin coats of this product.
  • Easy 2-Step Sandless Method - Thoroughly clean and prep hull using 92 Bio-Blue and a Scotch-brite pad as described above. Make sure that the entire surface has a dull, frosty finish. Wipe surface to remove any excess moisture and apply two thin coats of Neptune 5.

Bare Wood:

  • Bare wooden hulls should be sanded thoroughly with 80-grit sandpaper and wiped clean of sanding residue.
  • A coat of 6627 Tie-Coat Primer thinned 25% with 97 Epoxy Thinner should be applied directly to the bare wood.
  • Allow drying 4 hours and then applying two un-thinned coats of Neptune HRT per instructions.
  • Existing, hard antifouling paint should be thoroughly sanded.
  • If priming is necessary on bare wood spots, apply a touch-up coat of 6627 Tie-Coat Primer thinned 25% with 97 Epoxy Thinner to these areas.
  • Then apply the subsequent coats of Neptune HRT.

Steel Hulls:

  • To remove loose rust and scale from the metal surface, scrape, sandblast or wire brush.
  • Solvent clean the surface to remove grease and dirt then apply one or two coats of Pettit 6980 Rustlok Primer followed by two coats of Pettit 4700/4701 High Build Epoxy Primer.
  • Follow with Neptune HRT.

Underwater Metal Parts:

  • Abrade to clean bright metal by scraping, sandblasting or wire brushing.
  • Solvent clean and apply one thin coat of Pettit 6455/044 Metal Primer*. Let dry two hours and apply two coats of Pettit 6627 Tie Coat Primer. Let the second coat of 6627 Tie-Coat Primer dry at least four hours and apply Neptune HRT.


*These are simplified systems for small areas. Always read the labels or tech sheets for all products specified herein before using.

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California Residents: WARNING Cancer and Reproductive Harm -




Google Product Type:
Paint Type:
Hard Antifouling
Number of Seasons:
Single Season
Is Boat Trailerable:
Hull Material:
Fiberglass, Steel, Wood
Water Type:
Brackish Water, Fresh Water, Salt Water
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