Hello Bob, Georgs Kolesnikovs has forwarded your message posted to the TW list. Here is a snippet from a recent nine page paint specification provided during the design of the 38 foot tug yacht, NIDAROS. It is of interest here partly because the vessel has a steel hull and aluminum house, so the painting of both metals is addressed in the paint spec. The following is an excerpt, and is the portion most relevant to your questions as they would be addressed using the Devoe paint system... ------------------------------- Interior Paint Coatings All interior STEEL surfaces will be cleaned, brush blasted and then primed with Devoe 201 primer or Devoe 236 high build. Where blown in polyurethane insulation will be applied, the coatings will have a minimum thickness of 16 Mils DFT. Where cut-sheet foam insulation is to be applied, the primer will have a minimum thickness of 16 Mils DFT. On any STEEL surfaces exposed to view (areas such as the forepeak and the lazarette which will remain uninsulated and without ceiling) a minimum of two coats of Devoe 229 will be applied over the Devoe high build coatings. Devoe 229 color coating is not highly solvent resistant. Therefore, all bilge areas below the second longitudinal from the keel will be treated differently. These bilge areas will receive three coats of Devoe 236 as a final coating over whichever primer has been used. Bilge areas will receive no color coatings. All interior ALUMINUM surfaces will be cleaned, lightly brush blasted, cleaned again, and then primed with either Devoe 201 Primer or Devoe 236. Where blown in polyurethane insulation will be applied, the primer will have a minimum thickness of 4 Mils DFT. Where cut-sheet foam insulation is to be applied, the primer will have a minimum thickness of 8 Mils DFT. Thermal Insulation Blown in Polyurethane foam will be used throughout the interior as thermal insulation, except for certain areas which may require the use of cut sheet foam insulation (such as the sides of the aft cabin). Polyurethane foam and cut sheet foam insulation will be applied over the Devoe coatings as detailed above. Cut sheet foam insulation will be a firm grade of Ensolite, or a fire retardant grade of Neoprene. There will be no thermal insulation below the second longitudinal in all bilge areas. Blown in polyurethane foam is extremely flammable and is highly toxic when burning Blown in polyurethane foam is not entirely closed cell, so absorbs water and other liquids as well as any strong odors present. In consideration of those characteristics, a fire retardant formulation of Polyurethane Foam will be used if available. All foam insulated surfaces will additionally be spray painted with a minimum of two coats of Devoe Devflex 601, a water-based fire retardant enamel, or its equal. Engine Room Sound Attenuation Sound attenuation will be given a top priority. There will be no thermal insulation in the engine space. Instead, sound deadening materials will be used against the painted hull surfaces. Sound attenuation will be addressed on four fronts: Structure Borne Sound Isolation: Soft Mounts, Flexible Coupling, Flexible Stuffing Box will be required for the propulsion engines. Generators and auxiliary mechanical equipment will also have flexible isolation type of mounts to prevent structure borne noise. Equipment requiring structure borne noise attenuation via isolation mounts includes: Propulsion Engines; Drive Lines; Watermaker Pump; Refrigeration Unit; Ventilation Fans; Water Pressure Pumps. Structure Borne Noise Absorption / Dampening: Areas such as Engine Girders; Hull Surfaces adjacent to the Engine Girders and directly above the Propeller will have weighted sound absorption / dampening materials applied. Materials will be specified from readily available sound attenuation products. Air Borne Noise Isolation: All avenues for air borne noise between Engine Room and Accommodation Spaces will be sealed tight, including mechanical and electrical chase ways after installation of plumbing, cables, and wiring. Air Borne Noise Absorption: All surfaces between engine room and living quarters shall be insulated with sound absorbing foam on the Engine Room side. Sound barrier foam to consist of 2" total, including White or Silver Mylar surface coating, foam absorption layer, weighted vinyl damping layer, and foam de-coupling layer. Installation to be done in such a way that the insulation will be mechanically captured. All edges and joints to be sealed with Silver or White Mylar surfaced tape. All engine room air ventilation ducting will be treated with the same materials to a thickness of 1.5" total. ------------------------------ It should be noted that a more elaborate sound attenuation specification would be in order for maximum effectiveness, especially on a larger vessel. However, the above is an outline of the most effective primary sound attenuation strategies. I do not monitor the TW list, so I will receive only replies or queries sent to me directly, as below... All the best, Michael Kasten ____________________________ Kasten Marine Design, Inc. redpath@olympus.net http://www.kastenmarine.com