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toms are subject to fouling from marine life. In the case of wooden ships, marine borers have always presented a problem. Steel ships have the disadvantage of corroding. Paint and anti-fouling compositions are the best known means of over- coming the ravages of decay, rust and incrustations of marine life, Some idea of what fouling of a ship means in dollars and cents can be gained from Sabin, who in his ‘“‘Technology of Paint and Varnish’’ quotes the late Admiral Bowles, a former chief constructor of the navy, as authority for the statement that, “while the fouling of the battleship INDIANA between her launching and trial was very slight, it was sufficient to make a difference to the builders of $100,000 in the premium earned for speed, It probably increased the resistance of the ship about 15 per cent, A ship subject to ordinary serv- ice, staying in port about half the time, will foul so rapidly that in from six to nine months there will be a loss of speed of from 25 to 40% per cent; where ships are running regularly the loss is less.’’ (Trans. AM. Soc. C.E., Vol. 36, p. 494). This loss means days of delay, added fuel costs, and all other costs propor- tionally higher for the service ren- dered, Suitable anti-fouling compositions for steel or iron vessels are of basic ferric-oxide, incorporated in a _ ve- hicle that makes these paints dry to a smooth finish avoiding friction and helping to prevent the adherence of animal and plant life. They should be easily applied and dry with suf- ficient speed to allow the return of the ship to the water shortly after application; Poisonous constituents employed in these finishes are usu- ally mercury and copper oxides. Properly formulated, these paints should soften slightly with water to permit poisons to dissolve so as to be available to the organisms which infest the vessel. Elasticity to with- stand expansion and _ contraction from temperature extremes is es- sential and a slimy film discour- ages adhesion of these growths. Paints of this character should be applied up to the light load line. The frequency of the applications de- pends upon the waters travelled. Between the full and light load lines the use of special boot-topping paint is recommended to withstand the extreme alternate conditions of exposure to salt water and air, heat and cold. These are obtainable in colors, as are other finishing coats. Hull and Deck Finishes A new aspeet to consider in the selection of hull paints is the heat deflection value of paints, Just as white paint is the most efficient re- flector of light, it is the best de- flector of heat, being considerably more efficient than metallic alumi- num and darker shades of oil paints. White paint not only looks cooler, it is cooler. Some time ago the Cun- ard line announced their plans to paint the FrANcontA white for her next world cruise. This decision was made after engineers reported that from observations taken during cruises of the Mauretania to the West Indies it was found the liner was from 7 degrees to 9 degrees cooler in her white dress, Not only does white paint deflect heat rays of the sun, it increases ra- diation of heat from within, increas- ing passenger comfort and facilitat- ing keeping perishable goods. Tank- ers carrying volatile liquids will find evaporation reduced and refrig- erator ships will find savings in the cost of refrigeration. The most satisfactory hull finish- ing paints are of the multi-pigment oil and varnish type. High grade pigments are important in securing colors that withstand the constant salt spray and give good appearance. It is also important that these pig- ments be suspended in a_ vehicle sufficiently elastic to withstand sun heat and yet be hard enough to stand up under abrasion against the docks. Properly formulated. hull paints will work easily under the brush, cover solidly, dry quickly, permit re-touch- ing all abrasions and give a full gloss finish capable of withstanding for the longest possible time, the severe exposure which this type of paint must actually meet, Seuppers or runways, steel decks and cargo holds are effectively treat- ed by painting with iron-oxide base paints, The exact composition varies according to the special conditions each surface is subject to. Paints specified for steel decks must with- stand hard wear. MARINE REVIEW—June, 1935 In the case of wood or canvas decks, multi-pigment oil and varnish paints are recommended. Paints formulated for this specific applica- tion will bond better, afford maxi- mum protection and possess the nec- essary elasticity for this type of sur- face at the same time they will withstand wear and abuse. Frequently the desire is to retain the natural, bright color of the new wood. Where linseed oil or other fa- miliar preparations are used the re- sult is usually meager protection for a short period of time and a marked tendency for the deck wood to dark- en badly. Special wood deck sealers are obtainable and highly recom- mended for natural finish decks. This deck seal oil is ideal for seal- ing, preserving and surfacing wood- en decks. When used on new decks the natural, bright color of the wood is definitely preserved. It is also es- pecially effective in sealing wood fibre raised by frequent sandings, and prevents raising of the wood fibres as well as water proofs the surface, In the case of new canvas covering, the recommended practice is to apply a coating of liquid white lead. This will soak up into the can- vas, after which, it should be painted on top with canvas deck-seal gloss paint. Inasmuch as the fine appearance of any ship depends so much upon the finish of the super-structure, only highest quality deck house and bridge paints should be used, wheth- er they be white or in color. Fin- ishes of this character must be re- sistant to the most severe exposure, they must be washable, apply easily, cover well, withstand chemicals and not discolor. While multi-pigment full-bodied oil paints and long oil (Continued on Page 46) 19