2.3 Selection of Installation Method

The Seakeeper 9 can be affixed to the hull structure using two methods 1) Bolt-In installation or 2) Bond-In installation. See figures below.

Option 1 would be applied when a metal structure or laminated metal plates are available for attachment. The Seakeeper 9 frame would fasten directly to hull structure or plates using isolation gaskets for metal-to-metal contacts and 16x M14X2.0 fasteners. Depending on the structure to which the Seakeeper is fastened, blind threaded holes or thru-bolting can be utilized.

Marine-grade aluminum (6061-T6, or equivalent) bar stock is recommended for both blind hole tapping and thru-bolt installations. For blind-hold installations, helical threaded inserts (Helicoils) with a length of 1.5 x bolt-diameter (21 mm) are required to ensure the strength of the tapped holes exceeds that of the mounting boats (Grade 10.9) which ensures a secure bolted connection between the Seakeeper and hull structure.

Option 2 would be most commonly used on a hull constructed of glass reinforced plastic (GRP) or fiberglass. For this option, four 11 in. (280 mm) long by 4 inch (102 mm) deep saddles are bonded to properly spaced and prepared structural members that are an integral part of the hull structure. Seakeeper recommends using a structural adhesive with a lap shear strength of 2000 psi (13.8 MPa) or greater. Careful consideration should be exercised by the installer while selecting the appropriate adhesive. Compatibility with the Seakeeper’s cast aluminum A356-T6 saddles, hull structure, and pot life are three important factors to consider. Proper surface preparation in accordance with adhesive manufacturer’s recommendations prior to installation is critically important. Recommended adhesives can be found in Seakeeper Technical Bulletin 90382 – Structural Adhesive Recommendations.