International Paint

A Tyneside Paint Firm That Invented Modern Antifouling

The company began as the Holzapfel Compositions Company, set up in Newcastle upon Tyne in 1881 by German brothers Max and Albert Holzapfel together with Charles Petrie, making marine coatings for the shipping trade on the Tyne. The International brand name followed as the firm expanded fast: it was operating in Russia, Denmark, Italy and Germany by 1889, registered in the US by 1901 with production in Brooklyn, and had factories in Sweden, France and Japan before the First World War. International supplied its first antifouling coating in that same founding year of 1881, which makes the antifouling side of the business as old as the company itself, not a later addition.

The real technical breakthrough came in 1974, when International researchers Alex Milne and Sandy Christie found that a copolymer built around tributyltin (TBT) methacrylate would erode predictably in seawater, continuously exposing fresh biocide instead of simply leaching from a hard paint film. That discovery created the self-polishing copolymer (SPC) category that every modern premium antifouling, International's own included, still descends from. TBT itself turned out to be one of the most toxic substances ever put into the marine environment, and the IMO's Anti-fouling Systems Convention, adopted in 2001, banned new TBT applications from 2003 and banned its presence on any hull from September 2008, forcing International and every rival to reformulate the same self-polishing idea around tin-free chemistry.

Reading the Range: Which International Antifouling Is Which

The Micron range is International's SPC backbone: Micron 350 and Micron Extra (the same product under different regional names) and Micron CSC are ablative self-polishing paints for actively sailed cruising boats, wearing away in proportion to how much the hull moves through the water, while Micron 66 is a true SPC built on the brand's own Biolux chemistry and sold specifically for superyachts, rated for 2 seasons and beyond and able to keep protecting a hull through long stationary periods when a lesser antifouling would foul at anchor. Sitting below that, the Cruiser and Interspeed lines use a harder, controlled-depletion polymer matrix that erodes more slowly and unevenly, a cheaper option aimed at boats that sail rarely or sit in a berth most of the season, at the cost of needing a harder sand-back before it can be recoated many seasons later.

At the top of the technology tree sits Intersleek, a fluoropolymer or silicone foul-release coating that contains no biocide at all and works by giving fouling organisms nothing to grip rather than poisoning them. Launched in 1996 as the industry's first patented biocide-free coating, AkzoNobel now counts more than 5,500 vessel applications and says Intersleek has helped save over USD 3 billion in fuel costs across the fleets that use it, with figures for its current 1100SR grade of up to 9 percent fuel savings and only 1.2 percent speed loss over a full docking cycle. It is mainly specified on large commercial ships and fast or frequently underway motor yachts, since foul-release coatings depend on the vessel moving enough to shed anything that starts to settle, which is why it is a superyacht and commercial option rather than a typical weekend-sailor purchase.

Its own local distributor was dismissive when three coats of Micron 99, applied on International's own advice, still fouled solid within seven months.

What a Litre Actually Costs, and What a Full Haul-Out Runs

Checked on 2026-09-23: Force4 Chandlery in the UK sells International Micron 350 at GBP 59.95 for a 750ml tin and GBP 109.95 for 2.5 litres, working out to roughly GBP 43.98 per litre at the larger size. SVB in Germany lists Micron Extra EU at EUR 55.97 per litre before VAT and shipping. In the US, Interlux Micron CSC runs roughly USD 366 to 381 per US gallon (3.785 litres) at West Marine and other retailers, which is about USD 97 to 100 per litre, noticeably higher per litre than the UK or EU price for what is fundamentally the same self-polishing technology. For scale, Hempel's budget Classic antifouling starts from EUR 23.95 at SVB, roughly half International's per-litre price, which is the real evidence that International is a premium-priced choice rather than the cheapest option on the shelf.

Turning that into a haul-out figure needs a coverage assumption, since International does not publish a fixed litres-per-boat table. Chandlery paint calculators use roughly 10 sqm of hull per litre per coat as a rule of thumb, with 2 coats standard. A 12 metre yacht's wetted hull area comes out around 40 to 45 sqm on the standard length times (beam plus draft) times 0.75 to 0.8 formula those calculators use, which needs about 9 to 10 litres of antifouling for 2 coats, roughly GBP 440 to 550 or EUR 500 to 560 in material alone, more again in the US at gallon pricing. A 20 metre yacht scales to roughly 100 to 110 sqm of hull and 20 to 22 litres, on the order of GBP 900 to 1,000 or EUR 1,100 to 1,250 in paint. Labor dominates the total the way it does with any coating: real-world quotes gathered by boat owners put a straightforward 40 foot US haul-out, prep and respray around USD 3,000 to 4,700 all-in, with haul-out fees alone running USD 10 to 20 a foot; a 20 metre superyacht-scale job is not quoted this way at all, since that work is priced per job by an approved applicator once they have seen the hull, not sold off a retail price list.

The Conditions the Data Sheet Doesn't Let You Skip

Across International's antifouling data sheets, the working range clusters around a minimum of roughly 5 degrees Celsius (41 Fahrenheit) surface and ambient temperature, a maximum around 35 degrees Celsius (95 Fahrenheit), and a hard ceiling on relative humidity of 85 percent during drying and cure, with the surface needing to sit a few degrees above the dew point to avoid moisture blooming into the film. A minimum of 2 coats is standard across the Micron ablative and SPC range, and drying and overcoat times are not fixed figures: International's own general guidance is that cure and overcoat windows extend considerably at the low end of the temperature range, so a cold, damp spring haul-out can turn an advertised same-day job into one that needs an extra day before launch.

Switching antifouling systems, or simply recoating an older hull, is not a straightforward repaint either. International explicitly warns against applying its antifoulings directly over tin-based (TBT) copolymer antifouling, and publishes a compatibility chart covering its own older products and rival brands that installers are expected to check before overcoating; where the existing coating is unknown, incompatible, or in poor condition, the recommended fix is an epoxy barrier coat such as InterProtect 2000E first. That is a real added cost and step that a boat owner comparing sticker antifouling prices can easily miss, since the barrier coat, its own cure time and its own minimum temperature and humidity requirements all sit on top of the antifouling job itself.

How International Stacks Up Against Hempel, Sea Hawk, Pettit and Seajet

Hempel, a privately held Danish group with no AkzoNobel ownership link, is International's most direct European rival, and owners comparing the two on the YBW Forum note plainly that Hempel costs considerably less, though not necessarily less over several seasons. Hempel's range spans the same way International's does, from the budget Classic line, listed from EUR 23.95 at SVB, up to the premium Mille NCT self-polishing paint rated around 13.3 sqm of yield per litre; forum posters comparing the two directly rate International's harder-wearing Micron 77 as needing only 2 coats and a single top-up every second year, against a faster-eroding Hempel Cruising Performer that needs 2 to 3 spray coats or 3 to 5 brushed coats and an extra coat for boats running above 15 knots, which is the basis for the forum argument that International can work out cheaper across multiple seasons despite its higher sticker price.

In the US, Sea Hawk, owned by PPG Industries, prices its Cukote self-polishing paint from around USD 100 a quart to roughly USD 329 to 380 a gallon depending on color, putting it in the same band as Interlux Micron CSC and Micron Extra rather than undercutting it. Pettit, part of the Kop-Coat Marine Group under RPM International, overlaps further still: Kop-Coat itself has said its own Pettit paint and the private-label West Marine Premium antifouling are very similar in formula and performance, which shows how much of the US bottom-paint market shares underlying chemistry regardless of brand. The one clear loss for International in independent testing is Seajet, made by the Japanese firm Chugoku Marine Paints: Practical Boat Owner's 13-location UK antifouling showdown ranked Seajet's 033 first overall, with International's Micron Extra a strong and consistent runner-up rather than the outright winner.

What Owners and Testers Actually Report

Practical Boat Owner's nationwide test, run across 13 UK locations from Plymouth to Rhu in Scotland, found Micron Extra was comfortably one of the top paints almost everywhere it was tried, taking 2nd or 3rd place at most sites even where it did not win outright, and the magazine noted that the higher-priced antifoulings, Micron Extra included, generally beat the budget options across the board. In brackish, boat-heavy water, a Trawler Forum member running both a 30 foot sailboat and a 35 knot center console mid-Chesapeake Bay reported Micron CSC's antifouling properties held for a solid 1.5 years before moss, slime and eventually barnacles gradually built up, a result in line with the paint's own multi-season rather than permanent claim.

Not every account is as positive. On The Hull Truth, owners describe Micron Extra SPC as needing an insane amount of stirring with a corded power drill to break up its consistency, warning that skipping that step leaves clumps and globs in the tin that never fully mix in. A more serious case surfaced on the YBW Forum, where an owner who applied Micron 99 in the Caribbean, on the advice of International's own technical department and with three coats professionally applied at the recommended rate, found barnacles spreading over the whole hull within seven months on a boat that moved from Trinidad to Norfolk, Virginia with only short stops, and got a dismissive response from the local distributor. Other posters split over the cause, one arguing film thickness rather than coat count was the likely culprit and another noting that particular year was a bad one for barnacles generally, but the case stands as a real, properly documented example of a premium International antifouling failing despite manufacturer guidance and correct-looking application.

International and Awlgrip: Same Parent, Different Job

The overlap in ownership is real and easy to misread as an overlap in product: both International and Awlgrip sit inside AkzoNobel's Marine and Protective Coatings business, both are supported through the same kind of dedicated applicator training network the group runs worldwide, and Awlgrip's own published materials explicitly point owners doing a full repaint to International (or its Interlux name in the Americas) for everything below the waterline, since Awlgrip makes no antifouling of its own. But the two brands are positioned at different points on the boat and, largely, at different points on the market: International's own topside product, Perfection, is a two-part polyurethane pitched at DIY-capable owners and general boatyards, well short of Awlgrip's dedicated, professional-spray, superyacht-refit topcoat system with its own separate warranty tiers running up to 36 months.

In practice, that split shows up clearly on a genuine superyacht refit: a yard will typically run Awlgrip above the waterline for the topsides and superstructure, and reach for International's superyacht-grade Micron 66 or an Intersleek foul-release system below it, treating the choice of antifouling and the choice of topcoat as two separate purchases, two separate applicator disciplines and two separate warranty conversations rather than one combined AkzoNobel product. An owner or a yard researching AkzoNobel yacht paint needs to know which of the two names actually answers their question: Awlgrip for the mirror-gloss hull finish and its own repaint economics, International (or Interlux) for the antifouling, and the biocide-free Intersleek option, that decides how the boat performs and looks below the waterline.

Für wen: Owners and yards choosing a below-the-waterline antifouling system for anything from a production cruiser to a superyacht refit, and anyone researching AkzoNobel's yacht paint who needs to know that International, not its sister brand Awlgrip, is the one that actually makes antifouling.