Marine coatings & corrosion control

Spurred by the tremendous rise in all marine costs during the past eight years, many suppliers of marine paint have developed sophisticated antifouling coatings to keep a ship's hull smooth and free of marine organisms, thereby reducing fuel consumption.

Other developments include improved anticorrosion formulations and solvent-f>-ee coatings that enhance safety in the shipyards.

and aboard vessels. Manufacturers of equipment used for hull and steel cleaning as well as corrosion fighting products such as anodes have also made valuable cost-reducing contributions in the past few years.

We asked the major manufacturers of corrosion control products and equipment to tell us about their latest developments and ongoing research programs, as well as their proven products.

The following review on marine coatings and corrosion control is based on the replies xve had received as we went to press.

AMERON Ameron of Monterey Park, Calif, has announced the development of several cost-effective marine coatings systems. Ship hull smoothness is produced with a cost-effective, permanent highbuild primer, followed by application of one of a series of new, advanced high-performance antifoulings.

These antifouling coatings reduce fuel consumption by providing long-term, broad spectrum fouling control and drag reduction.

The key to these products is a patented, controlled-release polymer used in several unique, proprietary compositions. Ameron's controlled-release organotin polymer allows for a variety of formulation possibilities. Antifouling systems range from an innovative, inorganic coating that combines corrosion and fouling control, to a polymeric co-resin AF system that provides controlled- release toxin and a durable, micro-smooth surface. These new systems provide similar protection against fouling, even for vessels tied up at a dock for several months.

Amercoat® 2162 provides both corrosion and antifouling protection in one coating. Tests have shown both fouling and corrosion control for periods ranging from 48 to 60 months with only two coats (6 mils DFT) over blasted steel. This system is durable and, on aging, micro-smoothness remains essentially unchanged.

Amercoat 2161 is a semi-ablative, inorganic AF coating suitable for use over inorganic zinc primers.

Amercoat 2161 functions by using Ameron's patented, controlled- release polymer and proprietary inorganic fillers, providing superior AF performance and drag reduction. Its inorganic zinc undercoat insures long-term corrosion resistance.

For maintenance and repair work where sandblasting to bare metal is not scheduled, Amercoat 2409 is a durable, broad spectrum, polymer-based antifouling coating. This product provides constant delivery of toxicant for fouling control while keeping excessive film thickness loss of the coating in check. Long durability promotes continuous microsmoothness to help lower drag resistance for extended periods, while also performing well under static conditions.

For more information on Ameron products, Write 11 on Reader Service Card ASTILLEROS DEL GOLFO Astilleros Del Golfo S.A., located on a 25-acre site in Madero Tampico, Mexico, is unusual in that it was designed and constructed solely to perform grit blast and tank coating operations, though pierside and engine repairs are also carried out, and there are plans to construct a graving dock to permit external hull blasting and coating. Wesley D. Wheeler Associates, Ltd. of New York City is ADG's exclusive representative for the United States and other areas not presently covered by agents.

The highly automated blasting facility is based on a closed system supplied by C.A.B. of Houston; some special components were designed by ADG and built by its own fabricators. Grit is supplied from hopper cars on a rail siding to the yard's two huge, top-loading silos, each of which holds 1,000 tons of grit. After screening and loading into the silos, the grit automatically drops to the lower pressure chambers.

From there the grit is fed to eight blasting lines at the base of each silo via a mixing valve that meters it into the compressed air. The air is supplied from a bank of large compressors via C.A.B. coolers that remove oil and water. Eight pipelines from each silo take the air/grit mixture to the ship at the pier.

On deck, the blast hoses are coupled into the supply lines.

Sixteen blast nozzles are operated on two 12-hour shifts per day, seven days a week. Blast pressure at the nozzles is about 100-110 pounds per square inch, and white to near white blast is accomplished at a rate of 70-90 square feet per nozzle per hour.

Using dehumidified air for ventilation, tanks are blasted, grit blasted, spot blasted when necessary, then grit swept to brighten the steel prior to final cleaning, vacuuming, and coating.

For more information and a free brochure on Astilleros Del Golfo, Write 12 on Reader Service Card ATLANTIC SANDBLASTING Atlantic Sandblasting & Coatings, Inc. of Tampa, Fla. now has available an 1,800-foot piersite capable of sandblasting and coating of internal tanks, decks, etc. Light d r a f t s of 26 f e e t can be accommodated at the facility.

Atlantic is currently installing a 7,000-square-foot office and warehouse complex. Included are the most modern compressed air and grit-handling systems available.

More than 5 acres of land area is available for other trades. It is anticipated that steel work will be tied in with the sandblasting and coating to offer vessel owners complete retrofitting capabilities.

Atlantic Sandblasting has been in the marine coating business for more than 20 years and has never had a coating failure or delayed a vessel from schedule.

For a free capabilities brochure, Write 13 on Reader Service Card BUTTERWORTH/ LIQUA-BLASTER Butterworth Systems' Marine Liqua-Blaster® unit for shipboard cleaning and descaling uses ultrahigh- pressure (10,000 psi) water blasting to remove rust and provide "white metal" surfaces for painting. Precision work is now possible, thanks to the variety of nozzles available, all of which are hand-changeable.

Generally, it takes about 15 minutes of use before a beginner can be called proficient with the gun of the Liqua-Blaster. Having learned how to use the tool the operator can do an outstanding job of water-only cleaning at a rate of about 3 square feet per minute.

For a more thorough white metal cleaning, sand is injected into the water stream. The use of sand, wet or dry, can cause sparking; therefore, sand should only be used in non-explosive environments.

Because of the high velocity of the water jet the sand impacts the surface at a greater force than in dry sandblasting.

As a result, it provides faster cleaning and uses less sand. As no dust is generated, respirators are not needed, and clean-up is a good deal easier.

An added benefit accrues with the Marine Liqua-Blaster unit in that a rust-inhibiting agent can be automatically injected into the water jet to protect cleaned surfaces against oxidation. The in- hibitor can be injected along with the sand, or during a final wateronly clean-up operation. The special rust inhibitors will not interfere with subsequent painting.

The Liqua-Blaster is available on a skid for deck mounting or with wheels, and has an eyebolt at the balance point for hoisting.

A typical system also includes two guns, all necessary hoses and fittings, and the Abras-I-Jector® sand injector accessory, and safety apparel for four men.

For more information on the Liqua-Blaster unit, Write 14 on Reader Service CardBUTTERWORTH/ SCAMP Butterworth Systems' Scamp® unit cleans hulls underwater, reducing fuel costs by reactivating antifouling paints. The amounts of fuel wasted in carrying unwanted barnacles, seagrass, and other forms of marine life is mind-boggling. With the very high cost of fuel today, shipowners throughout the world are cutting costs with Scamp. Scamp underwater hull cleaning programs are available worldwide.

It is estimated "Free World" trading ships use some 126 million tons of fuel each year. A savings of at least 6 percent would be worth looking into. Six percent represents 7y2 million tons. This savings could be realized by periodic underwater hull cleanings.

With bunker fuel prices over $215 per ton, this would represent a savings for the "Free World" fleet of more than $1.6 billion.

The Scamp underwater hullcleaning machine is a set of three special rotating brushes mounted in a saucer-shaped unit in the center of which is a unique clamping impeller that holds the machine to the hull surface with a force of 1,000 pounds. The machine is controlled by professional scuba divers, or remotely from a workboat. In use, the Scamp unit is controlled to advance, stop, or reverse, or hold a parallel line of motion as it cleans a five-foot-wide swath. Because the sides, not the tips of the c l e a n i n g b r i s t l e s are used, a scything action is achieved that will not harm protective coatings.

The Scamp machine is hoisted into and out of the water by an accompanying workboat, which provides operating power. And as the time required to perform a complete hull cleaning generally runs 4 to 16 hours, depending on vessel size and degree of fouling, the cleaning operation can usually be conducted during loading or discharge, with little or no time loss due to the hull cleaning itself.

The Ship Research Institute of Norway has led the development of antifouling coatings designed to be reactivated at 12-month intervals using Scamp machines with specially designed brushes.

The antifouling coating is significantly t h i c k e r than ordinary coatings, and leeches its poisonous cuprous oxide into the sea.

After about 12 months, an inactive layer develops at the top surface, reducing the leeching rate.

When this happens and a color change occurs, it indicates that Scamp machine t r e a t m e n t is called for, and reactivation is easily achieved.

For more information on the Scamp machine and locations of worldwide cleaning stations, Write 15 on Reader Service Card CAMREX As a major supplier of specialized marine coatings Camrex Limited of Sunderland, England, is constantly trying to strengthen its "armory" of paint systems, and new systems are constantly being developed and evaluated.

These new coatings strengthen the Camrex product range with particular reference to the marine field, a major business area for the company. Some of the areas within the marine field where Camrex has particular expertise are described below, together with brief descriptions of coatings developed for each.

Chemical tank linings is an area in which Camrex has a great deal of experience, the trade name Camkote known worldwide to be synonomous with high-performance coatings. A new addition to Camrex's line is Camkote EP, a h i g h - p e r f o r m a n c e , two-pack epoxy coating formulated to provide outstanding resistance to a wide range of chemicals, solvents, and oils. This product is intended for general tank lining use, including the parcel tanker trade, where the wide variety of aggressive cargoes carried can severly damage less sophisticated coatings. Camkote EP has been designed to avoid any such problems and provide the shipper with a coating that will allow carriage of a wide cargo range.

The importance of providing adequate corrosion protection for the often neglected area of ballast tank linings has long been realized at Camrex. As such, several coating types have been developed.

These include pitch epoxies (D.T. Kote), pitch polyurethanes (NOP 6U and 6L), plasticized pitch compositions, solvent- free coatings, and the internationally accepted NOP range.

An interesting- development in this field has been progress towards a light-colored ballast coating.

The corrosion protection aspect of this system is also under investigation. The current trend is ballast coatings that are both less toxic and pose less of a potential fire hazard. Accordingly, the research work on water-based coatings has been intensified as a major area for new systems.

Ablative antifoulings represent the culmination of many decades of work aimed at providing a constant biocide output from the paint surface. This is achieved by seawater action upon the polymer surface layers. Thus these surface layers are constantly renewed, exposing fresh biocide.

Camrex C-Pol incorporates the traditional biocides combined with new organo-metallic p o l y m e r s, providing an antifouling paint with good antifouling properties in both static and dynamic situations.

The above product areas are indicative of the wide range of aggressive conditions under which Camrex coatings are required to operate. Many years of both technical and practical expertise has enabled Camrex to perfect these systems which, allied with the close technical supervision that is a feature of all Camrex contracts, insures optimum system performance.

For additional data on Camrex products, Write 16 on Reader Service Card CARBOLINE Carboline Company of St. Louis has compiled data covering more than 30 years of successful experience in the protective coatings field. Recommended Carboline Marine Division coating systems are based on laboratory research and technology combined with extensive ship and shipyard background.

Since the company was founded in 1946, it has built an enviable record in coating research and development, and has developed specialized coating systems suited to the requirements of the marine industry. Many systems are based on Carbo Zinc® 11 and Carbomastic® 15 as prime coats.

In many cases, extensive surface preparation for maintenance coatings application has become very expensive. Carboline recognized this problem and has developed a marine system based on Carbomastic 15, a self-priming, high-build, aluminum epoxy mastic that has excellent adhesion to rusted steel and most aged paints.

This system is said to provide better corrosion resistance and performance than conventional coal tars and epoxies over minimum surface preparations.

For maintenance work, a sweep blast of the existing coatings to tightly bonded material is an acceptable surface preparation. A single maintenance coat of Carbomastic 15 has required a minimum of touch-up since the system was first applied (six years to date).

The use of an overall coat of Carbomastic 15 results in a smooth, uniform surface appearance that helps eliminate the checkerboard effect often noted in other systems that are partially touched up in drydock at two-year intervals. It has excellent flexibility and weathering properties, and normally requires no topcoat. However, Carbomastic 15 may be topcoated with most antifoulings, epoxies, polyurethanes, chlorinated rubbers, and acrylics if desired.

Carboline recommends the use of either Carbo Zinc 11, an inorganic zinc, or Phenoline 373®, a modified phenolic for marine tank lining applications. Using a combination of tanks coated with these two systems, the Carboline Company feels that a maximum number of cargoes can be carried with a maximum amount of versatility and flexibility per vessel.

Phenoline has excellent chemical chemical resistance and is an effective and economical lining system for steel tanks carrying dilute acids, caustic soda, salt, or solvents, and is also recommended for tanks carrying wet or dry food products.

It is a thermosetting material.

Carboline's experience does not stop with effective corrosion control systems. Knowledge of proper recommendations for the service, good application techniques, and dependable servicing are strong assets in assuring customer satisfaction. The Technical Service Department, working in conjunction with the Marine Division, makes certain maximum service life is obtained.

In the marine industry especially, the availability of worldwide servicing and supply is essential.

Trained Carboline representatives are located throughout the United States, Canada, Europe, and more than 25 foreign countries. Their experience provides the backup for the specifier's judgment when recommending corrosion resistant coatings systems.

For more information on Carboline products, Write 17 on Reader Service Card CHESTERTON A corrosion preventive protection system for shipping and other marine applications has been formulated by A.W. Chesterton Company of Stoneham, 'Mass. The six products in the system include three for above the waterline and three others for engine room applications and when white metal finish sandblasting is a consideration.

Rust Transformer, Chesterton Universal Primer, and Urethane Enamels are designed for above the waterline use on a ship. Rust T r a n s f o r m e r electrochemically transforms rust into a sound base for the Universal Primer. Transformer eliminates sandblasting and strong acid treatments, and prevents further rusting with a passive, insoluble film.

Cold Galvanizing Compound, Heavy-Duty Rust Guard, and Chesterton Moisture Shield are appropriate for engine room applications when electrical relays may be endangered by exposure, or where white metal finish sandblasting is a possibility.

The Universal Primer and the Cold Galvanizing Compound resist corrosion and provide a firm base for finish coatings to be applied.

The Primer can be applied to any firm metal surface or over the Rust Transformer. Primer has withstood 2,500 hours of salt fog. The Compound is a 95 percent pure zinc coating that protects surfaces by sealing off water, moisture, and mild acids. It protects galvanically by sacrificing itself to oxidation instead of allowing the base metal to rust.

Long-term corrosion preventive protection is achieved with Urethane Enamels, which are virtually lead-free and have no lead compounds or photochemical solvents.

No catalyst has to be added; this eliminates pot life problems and the possibility of errors in mixing.

Short-term corrosion preventive protection is achieved with H e a v y - D u t y Rust Guard and Moisture Shield. The first protects like a paint, but is more economical and can be removed easily with solvent type cleaners.

A single application of the product protects against moisture, weather erosion, and contact marring.

It can be applied without cleaning over firm rust.

Moisture Shield prevents rust and displaces moisture, creeping under dirt and oil. It leaves a barrier film that protects against salt spray, moisture, and other corrosives.

For more information and a free booklet on Chesterton products, Write 18 on Reader Service Card DEVOE MARINE Devoe Marine Coatings Company of Louisville, Ky., a division of Grow Group, Inc. has during the past two years started to market four new products. Bar- Rust is a water-based, hard permanent coating designed for application in ballast tanks, forepeak tanks, void spaces, or any area subject to rust where grit blasting is prohibited because of cost or location. It will adhere to tight rust and converts this rust to a passive state. This tough, flexible coating provides longterm protection against further rusting, abrasion, or damage.

Bar-Rust is a safe coating. It contains no organic solvents and will not burn. This coating can be readily applied over rust, old paints, and even damp surfaces using standard airless spray equipment, and can be touched up easily by brush or roller. The rapid dry, light colors, and minimal surface preparation make this product ideal for many marine applications.

Devran 234QC is a high-performance, corrosion control coating designed for exterior hulls, ballast tanks, offshore equipment, and inland waterway vessels. It is a high-solids, high-build coating that provides outstanding water resistance and durability in a one-coat application.

Two f e a t u r e s make Devran 234QC desirable for marine ap- plications. The low temperature cure (it will cure below 0 C) allows shipyard and offshore painting- to proceed throughout the winter months. And it has tolerance to many of the contaminents found in shipyards without hurting its almost permanent corrosion control protection.

Devoe's ABC Anti-Fouling systems provide complete fouling protection, and a smoothing effect that reduces fuel consumption.

ABC-AF systems consist of contrasting red and blue coatings that slowly ablate away, thereby increasing hull smoothness and preventing attachment of fouling organisms. The high concentrations of cuprous oxide and optimum levels of organo tin compounds insure static protection while the ablative smoothing action proceeds as the vessel is under way.

ABC-AF systems are compatible with all high-performance and chlorinated rubber bottom coatings in good condition. There are more than 70 major ships presently using the ABC-AF systems, operating in all seven seas.

Devflex I is a fire-retardant, water-based enaniel designed for interior use. This product replaces the solvent-based chlorinated alkyd now in common use.

It is safe during application because it contains no solvents or solvent fumes. It dries rapidly, thereby speeding up the painting operation. Devflex will withstand temperatures up to 2500 F.

This new enamel is compatible with alkyd primers and old alkyd enamels. It is flexible and can be applied directly over insulation without cracking. A water-based primer is also available that will not rust bloom when applied over ferrous surfaces.

The outstanding color retention, scrub resistance, ease of tinting and application make Devflex an ideal product for Navy and passenger vessels requiring fire resistance for interior coatings.

For additional information on Devoe Marine coatings, Write 19 on Reader Service Card DU PONT The Du Pont Company has been active in the marine maintenance and new construction painting field for more than 40 years. The company's high-performance coatings reflect its long experience in preventing corrosion at more than 100 Du Pont chemical plants. The coatings are also used on the company's large fleet of inland and oceangoing ships and barges.

This extensive experience in protecting marine steel has led to the development of a new Marine Maintenance Painting Service that is now being test-marketed to shipowners. The service, similar in concept to the company's land-based Maintenance Painting Service, relieves owners of the total burden of maintenance painting. Under the program, owners sign a contract giving Du Pont responsibility for painting a ship or ships for a predetermined period of time, at an agreed-upon and guaranteed level of protection. All work is supervised by Du Pont Marine Finishes specialists.

Another development in the Du Pont Marine Finishes business is expansion of operations to a worldwide marine market. The company is now dealing extensively with foreign-flag lines in maintenance, new construction, and conversion projects.

According to Robert A. Sprout, manager of Du Pont's Marine Finishes group, shipowners have begun to shy away from inexpensive, low-performance coatings.

As investment in ships increases, according to Mr. Sprout, owners are now interested in high-performance coatings to protect their equipment.

Symptomatic of the trend is heavy sales of Du Pont's Imron high-performance polyurethane coatings. Imron provides superior protection to salt, sun, and chemical exposures while retaining excellent gloss and overall good appearance.

Many owners are using these finishes on virtually every piece of topside equipment.

Two recent U.S. Lines conversions are good examples. When the American Marketer and the American Merchant were converted from breakbulk/container service to total container operations, their superstructures were sprayed with Imron polyurethane.

The coating was chosen because heavy salt buildup requires frequent cleaning. Imron allows hosedowns for easy cleaning without damage.

Other products in the Du Pont Marine Finishes line are: Ganacin single- and dual-package, zincrich coatings; Corlar dual-build epoxy enamels; and Dulux metal protective and machinery enamel.

For additional information on Du Pont Marine Finishes, Write 20 on Reader Service Card ENGELHARD Two Engelhard Industries, Union, N.J., systems are designed to provide corrosion protection (Capac)® and f o u l i n g control (Chloropac)®.

The Capac (Cathodic Protection Automatically Controlled) system is designed to provide reliable impressed current corrosion protection for vessels and offshore rigs. Capac is reported to extend the period between drydockings ; reduce fuel costs; control corrosion under varying hull coatings, speeds and water conditions ; and provide a permanent alternative to short-term sacrificial anodes and special coatings.

The system had Maritime Regulatory Agency and Classification Society approval and can be installed on any type of vessel or rig. The system components are designed and manufactured by Engelhard.

The Cholorpac system is designed to provide continuous fouling control through electrolytic hypochlorite generation from seawater.

Chloropac is reported to eliminate erosion of heat exchangers ; keep water boxes and sea chests clean; keep piping clean, reducing fouling induced erosion corrosion. Surface condensers maintain their heat transfer rates, thus reducing fuel consumption.

For further information on Engelhard's systems and products, Write 21 on Reader Service Card ESGARD Esgard, Inc. of Lafayette, La., an international manufacturer and distributor of rust and corrosion preventive coatings, has developed a two-product integrated system that is said to provide lifetime protection for ballast tanks of ships, oil rigs, barges, and other marine vessels.

Both Bio-Kote and Bio-Gel are bio-degradable, practically nontoxic, and contain no petroleum oils or solvents. Bio-Gel is designed primarily for new construction and major reworking of such equipment. It is thoroughly compatible with Bio-Kote, which in turn provides long-term maintenance protection.

Until this new development, it was frequently necessary to undertake a costly removal of protective coatings applied during construction in order to apply a long-term coating. Bio-Gel may be simly sprayed on and in most cases Bio-Kote simply sprayed on or floatcoated later with no additional surface preparation.

Esgard will soon announce two additional product developments —Dri-Film and Enamel-Kote. Dri- Film is a thin film preservative for indoor storage of metal and machined parts. It can be applied by dip, brush, or spray and dries quickly to a clear, non-tacky film.

Because it is non-tacky, it does not interfere with normal machining operations and can be easily removed with petroleum solvents. It can be topcoated with Esgard Equipment Kote for outdoor storage.

Enamel-Kote is a self-priming maintenance enamel. It features non-toxic rust inhibitors to insure corrosion protection without the use of lead, chromate, or other environmentally undesirable components. Enamel-Kote comes ready to use in any color without thinning or two-component mixing. It is designed to be used on surfaces varying from buildings to equipment to pipelines.

For additional information on Esgard products, Write 22 on Reader Service Card EUREKA Eureka Chemical Company of South San Francisco has supplied Fluid Film, Gel "B", to the maritime industry for more than a quarter of a century for the preservation of ballast tanks, voids, cofferdams, and other areas. This coating remains permanently soft and can be applied over tightly adhering rust and mil scale. Being a semi-fluid, it has no pinholes and does not develop cracks when the steel substrate flexes.

The long service life of Fluid Film has been documented by a recent ABSTECH report. As entry into ballast tanks is usually infrequent and traffic through these areas is minimal, the presence of a soft coating is not objectionable.

However, a firm coating for ladders and expansion trunks is desirable.

Moreover, in some ships, particularly LNG carriers, ballast tanks must be entered on a regular basis for inspection purposes.

In order to utilize the many advantages of Fluid Film throughout most of the tank and, at the same time provide a firm coating in those areas subject to frequent personnel traffic, Berma Film "BT" was developed.

Berma Film "BT" is a modified epoxy coating formulated for application without the necessity for sandblasting, only requiring a surface equivalent to Steel Structures Bainting Council Specification SSBC-SP3-63, or better.

This two-component coating is applied in two coats of 10 mils each wet (8 mils dry) to provide a total thickness of 16 mils DFT.

Two colors, white and blue, are available, and either color may be used as the prime coat. The base coat should be allowed to dry a minimum of 8 hours and a maximum of 72 hours before the application of the second coat. If a non-skid surface is desired, 20-30 mesh Ottawa silica may be sprinkled on the top coat shortly after application.

Perma Film "BT" is compatible with Fluid Film, Gel "B". It is recommended that those areas be coated first where Berma Film "BT" is to be used, and a minimum of 7 days be allowed before re-entry into the tank and application of Fluid Film on vertical and overhead surfaces.

For additional information on Eureka products, Write 23 on Reader Service Card FARBOIL The Farboil Company of Baltimore continues to keep pace with the rapid changes in the requirements for marine coatings.

The conversion to high-build and high-solids coatings, the use of non-toxic pigments and fillers, and the increase required in flash points of coatings are only some of the developments that the company is currently pursuing.

Farboil has developed new zincrich coatings with long shelf life, and has added to its line of onepackage coating systems.

Farboil Ballastite® anti-corrosive coatings for ballast tanks have been modified to provide better corrosion resistance at lower cost, and the line has been broadened to meet requirements of most applications. There are now flotation products and sprayable types with soft or hard finishes.

An exclusive Farboil UV-resistant epoxy coating system has been developed that provides excellent outdoor durability compared with acrylic topcoats.

A program is currently under way to develop self-polishing organic antifoulants, and to achieve even greater service life for Farboil Sta Clean® antifoulants in order to increase the periods between repainting.

For additional information on Farboil products, Write 24 on Reader Service Card HEMPEL'S Hempel's Marine Paints presents a new dimension in selfpolishing antifoulings, the choice of a system custom designed for the individual vessel. Because ships are different, individual ships need individual protective coating systems. Hempel's offers the choice of coating systems for whatever conditions may be encountered.

Hempel's Nautic Modules cover all types of trading patterns.

From long sailing periods to short stays in port to frequent and long port calls, from normal to severe fouling conditions, Nautic Modules cover the situation. They are designed to cover a complete range of ship types, surface roughness, and drydocking interval.

Technically, Nautic Modules consist of Hempel's quality numbers 7680, 7685, 7687, 7690, 7695, and 7697 that, taken in various combinations, constitute a selfpolishing antifouling in which both the potency and polishing rate are varied according to individual ship requirements. Selfpolishing maintains the smoothness of new construction or reconditioning, extending the drydocking interval, and because Nautic Modules can be applied directly over the previous coat, drydocking costs are reduced.

Additionally, varying the wear rate and toxicity offers the owner the flexibility of matching the effective life of Nautic Modules with a vessel's overall maintenance plan.

Hempel's Technical Service Department will work out the ideal Nautic protective scheme and participate in every stage of the application from negotiations with the yard to a written, illustrated report on the completed job.

Hempel's Multi-Mil System is an immediate and flexible solution to the problem of pit corro- sion in cargo tanks. Traditionally, pit corrosion has meant either plate replacement or repair by welding or abrasive blasting, followed by painting. These options are all slow, difficult to impossible to carry out during a voyage, and expensive.

The Multi-Mil System tank repair process is based on a combination of solvent-free epoxy mastics— Hempadur 3543 and Hempel's Epoxy Filler 3531—and can be applied during a voyage. It does not require any large or complicated equipment, but fits right into the normal maintenance routine, offering an easy and economical solution to a complex problem.

For additional information on Hempel's Nautic Modules and Multi-Mil System, Write 25 on Reader Service Card HOOKER CHEMICALS When a coating is used to protect ships of the U.S. Navy, it must meet stringent requirements.

The Naval Sea Systems Command, which is responsible for preparing Navy coating specifications, recently approved the use of Hooker Chemical's Ferrophos enhancer as a replacement for up to 40 percent of the zinc pigment in zinc-rich primers.

The decision was made on results of long-term evaluations conducted by IMCO Laboratories, Inc. of Buffalo, N.Y. According to E.A. Morgenstern of NSSC's Coatings and Corrosion Branch, the results "demonstrated that a 40 percent Ferrophos replacement of zinc pigment provides performance at least equivalent to primers with a total zinc pigment." Ferrophos enhancer has been used commercially in zinc-rich coatings for more than seven years. Its use offers several advantages to both a paint manufacturer and an end user. The inert pigment is conductive and has the refractory properties of steel.

As a result, it improves welding and cutting operations on precoated steel. It also provides excellent intercoat adhesion.

Of special interest to paint manufacturers, when Ferrophos is substituted for up to 40 percent of zinc in a coating system currently approved by the Navy, retesting of the system is not required.

For additional information on Ferrophos, Write 26 on Reader Service Card HYDE PRODUCTS Hyde Froducts, Inc. of Cleveland formulates and markets Zimmite® Mud Remover, a proven product that has been used by vessel owners and operators to remove tens of thousands of tons of mud, saving literally millions of dollars. Use of Zimmite is useful during the tank cleaning process to remove built-up mud before applying any coating. Continuous use of the product via an automatic injection system is said to keep ballast tanks clean and free of corrosive mud. This is especially important when using any float-coat material that relies on clean steel for adherence.

The Zimmite Automatic Injection System consists of a holding tank for the mud remover, pumps to inject the Zimmite into the ballast system, and an electrical control panel for the pumps. The holding tank may range in size from 100 to 300 gallons. All are equipped with a sight glass for a visual indication of tank level, a low-level alarm that lights on the control panel, fill and drain ports, and a cover to keep out foreign material.

Generally, two high-pressure diaphragm pumps are used in the Zimmite system. They can be mounted separately or directly on top of the holding tank. Zimmite tank suctions are used to draw the Zimmite into the pumping system. The control panel consists of two push-button, lighted switches and one yellow warning light. Each switch controls one port or starboard feed pump (as marked). A light switch indicates proper operation. The yellow light is the low-level warning indicator.

System operation is simple.

When the ballasting procedure begins, the operator starts one or both pumps, based on full treatment or just one side. The yellow warning light comes on when the level in the tank drops below 25 gallons. However, the pumps will run when this warning light is on; there should be enough chemical to complete the ballasting.

For more information and free literature on Zimmite, Write 27 on Reader Service Card INTERNATIONAL PAINT In 1974, International Paint Marine Coatings met the challenge to combating rising fuel costs with the introduction of the Intersmooth SPC antifouling coating system. For the first time, a dynamic solution to an unsolved problem — control of fouling on underwater surfaces of ships — was now available. International Paint also resolved a problem that has persisted since the first ship was built, the progressive decline of speed versus power over time, due to physical roughening of the hull.

The unique characteristic of Intersmooth SPC antifouling is that its surface hydrolyzes when in contact with seawater, polishing as the water passes over the hull. Biocides, chemically and physically combined with the copolymer paint medium, are then released, protecting the surface from fouling. The rate at which Intersmooth SPC polishes is greater on peaks of physical roughness due to turbulence. The vessel's surface becomes smoother as it trades.

Intersmooth SPC performance extends far beyond the chemistry of the paint in the can. The key, as every shipowner knows, is experience. Monitored experience on more than 400 vessels controlled by nearly 200 owners— representing every major shipping interest in the world since 1974—has confirmed that Intersmooth SPC is the solution to: eliminating fouling penalties; improving vessel performance through hull smoothing; extending in-service periods; and maximizing operational revenues.

International Paint has not rested on its success. Fouling control achieved with Intersmooth SPC enabled operators to extend drydock intervals. But naturally, even longer periods at sea were desired.

Control of macroscopic fouling —weeds and barnacles—revealed that even slimes affect performance and must be controlled. Emphasized was the old problem of physical roughness, one costing money every day a ship remains at sea.

International embarked on a massive research program to understand and solve these newly recognized problems. International Dataplan was developed to quantitatively assess hull coatings' performance on all types of vessels, under all operating conditions.

International Paint Marine Coatings worked in collaboration with universities and other research institutions to develop new techniques to measure and analyze hull roughness. Scientists at International Paint's worldwide Research Center then refined and tested new Intersmooth SPC formulations.

Intersmooth SPC keys on the concentration of biocides and their corresponding "release" rate. Products can be engineered with different characteristics to cope with different circumstances, ranging from the rate of biocide release in static conditions, to the rate of hull smoothing.

Accelerating experience at sea, in the drydock, and the laboratory, has enabled International to recognize that no singular product product can provide all the answers.

As a result, the Intersmooth SPC Marine Coatings Family was created.

Intersmooth SPC-4 has the most extensive in-service track record within the Family. It was engineered for general trading conditions, for in-service periods of up to 30 months. It combines predictable fouling control with proven smoothing characteristics.

Intersmooth SPC-9 offers the same benefits of Intersmooth SPC-4, while specially designed for more severe fouling environments and low activity vessels.

It has been used extensively for ships operating from Japan, where fouling is severe, and for ships operating with repeated idle periods (especially on coastal routes), such as ferries.

Intersmooth SPC-20 is the newest member of the SPC Family.

It polishes more slowly than the other products, and used in combination with the SPC-4 or SPC-9 system, allows extended in-service periods beyond 30 months. It is also recommended where accelerated polishing might occur.

For additional information on International Paint's products, Write 28 on Reader Service Card JOTUN MARINE The substantial attention given during recent years to the possibility of bunker savings by using more sophisticated bottom treatment systems has, to a large extent, ended in a discussion of the efficiency of various antifouling types and especially selfpolishing and reactivatable antifoulings.

According to Jotun Marine Coatings, which has marketed selfpolishing antifouling types (Takata LLL) for many years, this type of modern antifouling is a part of the total answer.

Jotun feels it is necessary to consider the total concept, which Jotun calls Underwater Hull Surface Management (UHSM). When studying the complex problem of friction between underwater hull and seawater, a number of factors should be considered. Roughness can be caused by a variety of problems including corrosion, flaking, blistering, faulty application, etc. Step one in UHSM is eliminating this roughness by sandblasting back to bare steel (SA 2i/2).

A Jotun study, showing the relationship between bunker savings achieved and the payback period of the capital invested in the blast cleaning, reports that maximum payback period of the extra investment is 13 months.

More likely, Jotun states, it would be closer to 4 months, and return of the extra capital invested as high as 75 to 250 percent. That study involved a 280,000-dwt ship, with an investment of $545,000 in sandblasting and a more sophisticated primer system.

The self-polishing antifouling, such as Jotun's Takata LLL, does not leave a porous skeleton as the toxicant is chemically bound to the resin so the paint film slowly dissolves in the seawater.

During drydocking, it is sufficient to clean the hull and apply new coats of antifouling directly over the old.

The reactivatable type of antifouling, such as Jotun's Seamaster, is based on different principle.

This is built up the same way as the traditional longlife antifoulings.

With this type, however, the skeleton can be removed periodically by a special underwater brushing machine. As a result, the service life of the antifouling film can be prolonged extensively— up to 4-5 years—between each drydocking depending on the original film thickness. By undertaking reactivation prior to drydocking, there will be no porous skeleton left on the surface when the ship is in dock. New antifouling can then be applied directly on top of the old the same as the selfpolishing antifoulings.

In both cases, either by using a selfpolishing antifouling or a reactivatable antifouling, it is possible to maintain the original smoothness of the underwater hull. Experience, Jotun reports, shows it has been possible to maintain smoothness on the underwater hull for as long as 11 years.

For further information and free literature on Jotun products, Write 29 on Reader Service Card KAISER CHEMICALS The Kaiser Chemicals Division of Kaiser Aluminum & Chemical Corporation manufactures and markets a line of magnesium and aluminum anodes used for cathodic protection in marine environments.

The Tulsa Metal Products facility has an aluminum anode capacity of 12,000,000 pounds, and produces a proprietary non-mercury aluminum alloy (KA90) as well as a mercury-type aluminum alloy anode (KA95). KA90 comes in configurations for use as flush mount hull anodes, ballast tank anodes, platform and multipurpose anodes.

An ongoing quality control program and efficiency tests through electrochemical evaluation provide reliable seawater anodes for use on all types of offshore structures and vessels.

Magnesium ribbon anodes for ballast tank de-scaling are also available.

Technical services are available for evaluation of anodic requirements and performance. For a free copy of Kaiser's 20-page brochure "Aluminum Anodes for Cathodic Protection in Marine Environments," Write 30 on Reader Service Card METCO The U.S. Navy is testing a nonskid deck coating system based on arc-sprayed aluminum applied to helicopter deck areas. The system may last for years. It costs approximately $3.00 per square foot, including material and application, and will postpone major maintenance for at least five years.

The coating system has already logged five years of sea duty on the USS Truett and is still in excellent condition. Now the Navy has expanded its test program to the USS Hewitt, making the Hewitt the first "air capable" ship to have a full flight deck covered with the new non-skid coating.

Three additional Navy ships are scheduled to receive the coating system. It has civilian potential also, especially on metal walkways, which can become slippery when wet.

The non-skid system is applied by using off-the-shelf materials and equipment from Metco Inc.

of Westbury, N.Y. As specified in the Navy's Technical Manual "Corrosion Control for Shipboard Launch and Recovery Systems," it consists of an arc-sprayed aluminum coating plus two seal coats of Metcoseal SA sealer. The aluminum is supplied in wire form by Metco, and is applied with two Metco spray guns.

The goal is a non-skid coating that will last at least five years without major maintenance. This is more than double the service life of some coatings now in service.

The aluminum coating system is easy to apply. A standardized procedure is followed. First step is to prepare the deck surface by sandblasting a five-foot-wide strip that is arc-sprayed the same day with a 6-mil cover coat of aluminum for corrosion protection.

The arc-sprayed aluminum is applied immediately after the sandblasting so that moisture or other contaminants cannot form and weaken the bond between the coating and deck. This 6-mil cover coat is then followed with a 20 to 25 mil "high profile" coat. The heavier coating is sprayed so as to produce a surface profile that is as rough as possible in order to accentuate the non-skid character of the coating. As the final step in the coating system, the sprayed aluminum is sealed for greater corrosion resistance with two coats of Metcoseal SA silicon alkyd sealer. The Navy then applies a strontium chromate primer followed by an appearance of the traditional "battleship" grey.

For additional information on Metco products and services, Write 31 on Reader Service Card MOBIL CHEMICAL Mobil Chemical Company, maintenance and marine coatings department, supplies a complete line of high quality marine coatings for maximum protection and corrosion resistance in all marine environments.

The company manufacturers a unique single-package inorganic zinc rich coating called UNI-PAK.

Mobil reports UNI-PAK provides all the advantages of a two package material but is supplied ready mixed in a single container. It contains 82.5% metallic zinc in the dry film and provides excellent early water resistance. It can be applied with either conventional or alas equipment. It provides a smooth cured film surface which is uniformed in color.

Literature is available for Mobil which contains performance statistics for UNI-PAK as well as complete details and information regarding Mobil's entire line of marine coatings.

Write 36 on Reader Service Card PALMER PRODUCTS Palmer Products, Inc. of Worcester, Pa. recently introduced a tough one-part, non-skid deck coating free of organic solvents.

Designated Durapox PM-1191, this coating meets OSHA requirements.

PM-1191 consists of water base binder and abrasive particles.

Soap and water can be used for the cleanup operation. No red label is required, and it is safe for use in confined areas.

PM-1191 is said to be economical to use, easy to apply by roller, and maintains excellent adhesion to most types of surfaces.

It is resistant to water and chemicals whether the surface is dry, wet, or oily.

Another new product announced by Palmer is a marine hull-smoothing and repair compound named Redepox, which was developed specifically to meet the demanding needs of the marine industry. This fast-curing epoxy resin has excellent resistance to sea water and most chemicals.

Palmer Products provided the first approved paste repair resin to the U.S. Navy in 1956. Extensive use in marine and industrial applications over the past 25 years has provided the company with a proven background in epoxy resins development and use.

In filling pits and holes in ship hulls and rudders, Redepox trowels easily and feathers smoothly, thereby reducing machining time.

It provides a smooth, spreadable c o n s i s t e n c y with non-sagging qualities; if required, it can be painted. A one-to-one hardener/ resin ratio provides for simple on-site mixing and application.

For more information on Palmer's products, Write 32 on Reader Service Card PRODUCTS RESEARCH Products Research and Chemical Corporation, Glendale, Calif., has developed a series of polyurethane coatings specially designed to reduce maintenance and prevent corrosion. These coatings are based exclusively on the company's proprietary line of polyurethane polymers.

PRORECO® I, a seamless deck covering for interior spaces, consists of a corrosion-inhibitive primer, a flame-retardant polyurethane elastomer underlay - ment, colorful decorative chips, and a highly durable, non-yellowing polyurethane glaze. In service now for over 10 years by commercial and military marine users, PRORECO I has demonstrated significant weight and maintenance reduction advantages.

Corrosion of metal decks caused by water seepage and infiltration is prevented. The manufacturer reports the inherent flexibility, resilience, and impact resistance of PRORECO I enable it to withstand severe ship movement and mechanical abuse without cracking, splitting, or loss of adhesion.

A companion system, PRORECO III, has been designed for exterior weather decks. This sys- [...]