MIL-STD-2199A APPENDIX A
A.3.3 Flange preservation. Waterborne shaft flanges shall be preserved (coated) as follows: A.3.3.1 Shaft flanges enclosed within rotating coupling covers.
a. Commence flange preservation as soon as possible after the abrasive blast (see A.3.1.2.1.f).
b. Accomplish steps A.3.2.2.a and A.3.2.2.c through A.3.2.2.l, but in reference to the flange surfaces.
NOTE: Documentation already exists on CG 47 and DDG 51 ship classes to apply a Euronavy paint system to the waterborne shaft flanges in way of rotating coupling covers (AER's 68152 and 66076 apply, respectively). This documentation and associated Euronavy paint system may continue to be used in lieu of the polysulfide elastomeric coating specified above but only for the applicable ship classes outlined therein.
c. Once the coating is tack-free, remove the masking from the sleeves, flange mating faces, bolt holes, and bolt head/nut washer faces.
d. Apply a generous bead of sealing/fairing compound (see A.3.2.3) to the shaft-to-sleeve interfaces. Smooth/blend/fair the sealant with adjacent surfaces.
NOTE: Once the shafts are installed on the ship, the flanges mated, and the coupling bolts installed and torqued,
but prior to installation of the rotating coupling cover(s), the elastomeric coating (see A.3.2.2) shall be applied to the bolt heads and nuts as well as respective washer faces. This can be done by taking a small quantity of Parts A and
B of the coating, mixing them in the proper ratio, and applying to the areas with a paint brush. The elastomeric coating shall also be applied around the entire circumferential mating joint of the flanges. After the coating is tack
free it shall be spark tested. If there are any areas that spark, brush additional coating onto suspect areas. Following
cure, the areas shall be spark tested again. Repeat as necessary until a satisfactory spark test is achieved.
A.3.3.2 Shaft flanges normally exposed to seawater.
a. Commence flange preservation as soon as possible after the abrasive blast (see A.3.1.2.2.f).
b. Accomplish steps A.3.2.2.a and A.3.2.2.c through A.3.2.2.l, but in reference to the flange and sleeve end prep surfaces, as applicable.
c. If the shaft is configured with independent fairwater sleeve(s), apply sealing/fairing compound to fair the sleeve end(s) to the shaft in accordance with A.3.2.3.
d. If the shaft is configured with independent fairwater sleeve(s), apply GRP in accordance with A.3.2.4, beginning at the sleeve, over the end prep area, continuing along the straight section of the shaft, and extending as far up the flange fillet as possible.
e. For the remaining flange surfaces that cannot be properly covered with glass tape, one of the following two corrosion protection layers shall be applied:
(1) Two (2) coats of epoxy conforming to MIL-PRF-23236, Class 2. A minimum dry film thickness of
15 mils (0.015 of an inch) shall be achieved.
(2) A resin formulation containing 10 percent by mass of milled glass fibers after the straight run covering has been applied. Any resin remaining from step d above may be used or new batches of resin may be prepared. If new batches are prepared, 10 percent milled glass fibers shall first be added to the resin followed by addition of the curing system (accelerator and catalyst for polyesters and hardener for epoxies). A thixotropic filler (see 5.2.1) may also be added to limit resin drainage (up to 4 percent by mass depending on temperature). Four (4) coats of resin may be sufficient but the total thickness shall not exceed 60 mils (0.060 of an inch). Separate batches of resin shall be prepared for each coat since gelation (partial hardening) may occur before the next coat is applied. In coating the flange surfaces, care shall be exercised with regard to areas around and between bolts in order to avoid holidays or porosity.
NOTE: Regardless of which system outlined above is applied, ensure the masking in way of the bolt head/nut washer faces is removed before the first coat of either system has cured. For each additional coat, exercise extreme caution not to get any paint/resin on the washer faces.
f. Once the coating has cured, remove the remaining masking from the flange mating faces and bolt holes as well as the end(s) of the fairwater sleeve(s), if configured accordingly.
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