COATING SYSTEMS FOR RAST TRACKS AND TROUGHS

Overview
USS STERETT (DDG 104)
April 5, 2017. Sailors assigned to USS Sterett (DDG 104)
remove chocks and chains from an MH-60R Sea Hawk
helicopter. U.S. Navy photo by Mass Communication
Specialist 1st Class Byron C. Linder.

The Recovery, Assist, Securing, and Traversing (RAST) track is located on the flight deck and is used to secure aircraft to the deck and guide them in and out of the hangar. There are plates located on each side of the RAST track. The plates and the track trough are subject to mechanical abrasion and corrosive sea spray. The trough is prone to corrosion and is designated as a critical coated area in NAVSEA Standard Item (NSI) 009-32.

Typical Coatings Used

The RAST track plates and trough are both painted. The track plate also has nonskid installed.

Areas Not Receiving Nonskid

The primer and topcoat are anticorrosive coatings that are qualified to MIL-PRF-23236, Coating Systems for Ship Structures.

The MIL-PRF-23236 specification divides the coating system into four types based on the volatile organic compound (VOC) content. This specification has nine classes of coatings that are determined by the type of surface being preserved. For RAST track troughs, acceptable coatings include MIL-PRF-23236, Types VII; Class 5, 15b, or 17. As an alternative to the primer and topcoat method, NSI 009-32 recommends a single coat system using MIL-PRF-23236 Type VII, Class 17/18 paint.

Track Plate Receiving Nonskid

The primer and stripe coats are anticorrosive coatings that are qualified to MIL-PRF-24667, Coating System, Nonskid, for Roll, Spray, or Self-Adhering Application. NSI 009-32 specifies that within a zone or work area, proprietary primer and nonskid listed on the QPD for MIL-PRF-24667 shall be coated with the same primer and compatible topcoat. In general, the type of nonskid coating system selected is based upon the coating’s minimum service life requirements.

Surface Preparation

To ensure proper coating adhesion, special attention should be paid to the surface preparation of the track plates and trough. For surfaces that are painted and where nonskid is to be applied, SSPC-SP 10/NACE 2, Near-White Metal Blast or SSPC-SP WJ-2/NACE WJ-2, Very Thorough Waterjetting are acceptable surface preparation methods. SSPC-SP 11 Power Tool Cleaning to Bare Metal is acceptable for painted surfaces and for surfaces receiving nonskid where the minimum service life requirement is 30 days.

Depot Repairs

NSI 009-32 is the governing document for preservation requirements. Permitted coatings are specified in Table 2. All RAST track and trough coating system preservation efforts must be accomplished in accordance with NSI 009-32.

Ship’s Force Repairs

Ship’s force personnel are primarily responsible for maintaining the ship’s RAST track and trough until repair activity maintenance is scheduled. Naval Ships Technical Manual: Chapter 631 (NSTM 631), Preservation of Ships in Service – General and NSTM 634, Deck Coverings – General provide requirements, instructions, and guidance for surface preparation and coating application.

New Construction Ships

New construction ships are painted in accordance with the ship build specification for that class of ship.