Following is a brief outline of the kinds of coatings normally applied to marine vessels, and where on the vessel it is appropriate to use them.

I – Heavy-Duty, High Performance Coatings

 A. Two-Component, Aliphatically-Cured Polyurethanes, including Acrylic/Urethanes, Poly-ester/Urethanes, etc.

 Primary Utility – best coatings for resistance to degradation from exposure to ultraviolet light (UV resistance), i.e. exterior environment (weather) exposure.  Also excellent abrasion resistance; very good resistance to mild chemical exposure; unusually long-term durability; available in exceptionally high gloss (wet look) finish; or satin finish.  Excellent color intensity and longevity.

Limitations :  Not for immersion service of any kind, either internally inside tanks or exterior below the waterline of vessels.  Because of high-gloss finish, if used on floors or decks, must incorporate an anti-skid aggregate so the surface won't be dangerously slippery to walk on.

Very expensive on a per gallon basis, but the cost is justified on a per year of useful life basis because of long term durability and attractiveness of the finish.

SOMAY does NOT manufacture.  SOMAY does represent several major manufacturers including. Carboline, Pratt & Lambert, etc.

B. Two-Component, Polyamine or Polyamide-Cured (i.e. chemically-cured) Epoxies

This includes an enormous array of coatings available in a wide variety of percentages of volume solids and a broad variety of modifications that provide many unique, special properties for practically every conceivable surface protection and corrosion resistant coating requirement.

Primary Utility – Excellent abrasion resistance; excellent chemical resistance, including special modifications with glass flake, Novolac, etc. for resistance to extremely high concentrations of acids, alkali, etc.  Includes excellent resistance to both fresh and salt seawater, to sewage water, etc.  If you chose the proper epoxy coating, it can offer very long term durability and useful life and therefore surface protection; total immersion in water, sewage, chemicals, etc. for many years.  Available in different degrees of gloss, colors, etc.

Limitations:  Most epoxies lose their original gloss and become dull looking in relatively short exposure to UV (exterior sunlight); colors are not necessarily bright or intense, not necessarily stable or uniform, are subject to color shift and not necessarily uniformly, but this does NOT normally have any deleterious effect on the epoxy's abrasion resistance, chemical resistance, ability to withstand total immersion, etc.  Thus this limitation is essentially just an aesthetic factor.  Therefore sometimes epoxies are used as a prime coat or intermediate coat and an acrylic polyurethane is used as a top coat or finish coat for aesthetic reasons.  Together this makes an excellent coating system for exterior exposure above the waterline.  Proper surface preparation and coating application is essential to satisfactory performance.

Moderately expensive on a per gallon basis, but well worth the investment for long term durability and utility.  Epoxy coatings are the real work horses of paints for all the things they can do.  Very effective as metal surface primers and intermediate coats on practically every surface of a marine vessel, bottom, sides, top, interior, exterior, etc.  SOMAY/Carboline "Carboguard" 890 is an excellent quality cycloaliphatic amine epoxy mastic, high solids, high-build, high gloss, with excellent exterior weatherability in sea environments, plus it can be used in total immersion environments.

There are thousands of manufacturers of epoxy paints and thousands of variation of formulations for specific  uses. Prices generally reflect the quality and volume solids of the epoxy and the reputation of the manufacturer.  Since these are used for high performance jobs, it is not sensible to try to save money on an epoxy coating and risk using an inferior coating that could subject the substrate to possible degradation because of lack of surface protection.

SOMAY manufactures only one line of 2-component epoxies, our "HYCOTE" line for application under water, through the splash zone and above the waterline in one application operation.  It is a special purpose epoxy.  SOMAY is, however, a stocking distributor for a number of other epoxy coating manufacturers, including Carboline, Plasite, Sentry,  Semstone, Pratt & Lambert, Ameron, etc., so we have ready availability of any kind of epoxy anyone could ever possibly need.

C. Two-Component, Special Purpose Corrosion Resistant Metal Primers, including:

SOMAY/Carboline "Carbozinc" 11, an alkyl-silicate inorganic zinc-rich primer to protect steel surfaces galvanically.  Can be used in total immersion service, both above and below the waterline.  MUST be top coated, normally with epoxies – but never with alkyds.  Proper surface preparation and coating application is essential to satisfactory performance.

These coatings are relatively expensive on a per gallon basis, but their cost is always justified on a long term performance basis.  SOMAY does not manufacture these coatings, but SOMAY does serve as a stocking distributor for these coatings manufactured by Carboline, Plasite, Pratt & Lambert, Ameron, etc.  We highly recommend this as the base prime coat on any steel ship hull, top-coated with an epoxy.

II Moderate Utility, Moderate Performance Paints

 A. Alkyd Resin-Based (so called "oil-based") Paints, Solvent-borne (normally mineral spirits solvent)

A huge variety of alkyd paints have been made for many decades by practically every paint manufacturer.  Surface finish can be "flat" to "high-gloss" and every degree of sheen in-between.  Have moderate degree of abrasion resistance and scrub resistance, so are used as interior and exterior trim paints.  Can be formulated with a corrosion inhibitor included to be used as a primer on metal, such as SOMAY Product No. 636 and No. 1147, Ferrous Metal Primers, but this increases the price.  Cures on exposure to air – is slow drying, which can take days, particularly in humid, cool environments.  Can NOT be used in immersion situations.

An alkyd finish gets hard, even brittle over time, depending on exposure.  Light colors will "yellow" or "darken" over time, depending on exposure.  Sun exposure will "bleach" the colors. Alkyds (oils) can attract mold and mildew growth on the surface, depending on environment and exposure.  Alkyds (oils) do NOT have the same resistance to UV exposure.  Alkyds can be used to paint most surface areas of a vessel that will not be subject to immersion under water.

Alkyds are moderately priced – more expensive than acrylic (latex) waterborne paints, but less expensive than 2-component epoxies and urethanes.

SOMAY manufactures alkyd-resin (oil) based paints, especially SOMAY Product No. 237, an alkyd-urethane high gloss enamel, which we have made for over 40 years.  This product has been used on the exterior and interior of both pleasure craft and work boats for years, on exterior sides, decks, interior walls and trim, etc.

B. Acrylic Resin and Vinyl/Acrylic Resin (so called "latex") Waterborne Paints.

An extremely wide variety of paints, have been manufactured widely since the 1940's by every major and minor paint manufacturer.  Surface finish can be "flat" to moderately high gloss and every sheen in between.  Have relatively low resistance to abrasion and scrub resistance, so are used primarily as interior and exterior wall paints on buildings.  Used on marine vessels for interior cabin walls that do not need to withstand any abrasion or wear to the surface finish.  Heavy-duty, industrial strength, 100% acrylic-resin based semi-gloss enamels, such as SOMAY Product No. 630, can be used for both interior and exterior walls and trim on yachts and pleasure craft, but would not normally be used on work boats.

Can never be used in immersion service.  Finish cures by exposure to air and evaporation of the water from the applied paint film.  Drying time therefore is dependent on temperature and humidity of the atmosphere.  Has relatively good resistance to degradation from UV and exterior exposure and good color stability.  Can have mold and mildew inhibitors incorporated into the formulation. 

Are generally moderately to low priced, depending on the quality and volume solids incorporated into the formulation. The higher the percentage of 100% acrylic resin volume solids in the formulation, the more durable the applied coating will be, and the price will reflect the quality in the formulation.

SOMAY manufactures a complete line of acrylic resin and vinyl/acrylic resin, waterborne, architectural paints.

III Special Purpose Marine Paints

 Anti-Fouling Bottom Paints

These are formulated to be soft finishes which gradually disintegrate or wear away under water, continually exposing the poisons which were incorporated into the paint formula.  The poisons are supposed to inhibit the growth of anything on the painted surface underwater, such as barnacles, sea grasses, etc., which would cause the vessel surface to be rough instead of smooth and thus cause a drag on the boat moving through the water.

The incorporation of poisons in paint formulations is subject to government regulations.  These paints are expensive to manufacture and use, and have limited useful service life, so must be repainted frequently, the actual repaint schedule being dependent on how fast the vessel moves through the water, which affects the rate of erosion of the paints on the surface, the temperature and salinity of the water, etc.

SOMAY does not manufacture anti-fouling paints and our normal paint vendors do not manufacture these special purpose coatings.

SOMAY "HYCOTE" is NOT an anti-fouling coating.  However, it develops such a hard finish that marine growth has great difficulty adhering to the cured "HYCOTE" finish underwater.  SOMAY "HYCOTE" can withstand water blasting with 13,000 P.S.I. at the tip of the pressure cleaner. Since most marine growth on the bottom of vessels can be easily removed with water blasting at 8,000 P.S.I. at the tip, there remains a safety factor of approx. 5,000 P.S.I. when cleaning marine growth from a SOMAY "HYCOTE" surface.  The U. S. Coast Guard found no marine growth on the bottom of one of its Cutters coated with SOMAY "HYCOTE" even after 18 months continuous immersion service in the warm waters of the Gulf of Mexico!

November, 2002