2.5.3 Fiberglass Hull Preparation

1. Position installation fixture (Figure 19) on hull girders noting recommended clearances for maintenance from Figure 5 (in Section 2.2: Selection of Installation Location). Check that the screws fastening the saddles to the installation fixture are tight (Figure 21).

2. Mask hull area (Figure 20) around foundation saddles for easy clean-up and to create outline of surface area to receive adhesive (Figure 19). Ensure that the bond gap is within Seakeeper’s recommended thickness, or 3 mm if using Plexus MA590 or Sci-Grip SG300.

3. Raise fixture clear of foundation. Check all four mounting areas are co-planar to within 0.06 in. (1.5 mm) to each other, as well as parallel to the water line plane, as shown in Figure 21.

4. Thoroughly clean with alcohol or acetone all areas of girders to be bonded to remove any contaminates. Use new paper towels for cleaning, not shop rags.
5. Remove any paint or gel-coat from bond surfaces so that adhesive will bond directly to laminate fibers and resin.
6. Thoroughly sand girder bond surfaces with 80 grit sandpaper in a cross-hatch pattern. (IMPORTANT – BOND STRENGTH MAY BE REDUCED IF THIS STEP IS SKIPPED.)
7. Wipe surfaces clean from dust with alcohol or acetone using new paper towels, not shop rags.
8. Re-position installation fixture on girders and double-check that the adhesive gap is within the adhesive manufacturer’s maximum recommended thickness. Seakeeper recommends a maximum gap of 3 mm if using Plexus MA590 or Sci-Grip SG300.

Note: If bonding saddles to a metal structure, follow adhesive manufacturer instructions for metal substrates.