Mechanical Installation

Reference Documents & Drawings:

  • 90559 – Seakeeper 1 Generic Installation Guide
  • 90514 – Seakeeper 1 Bolt-In Clearances (Gives details of bolt stack also)
  • 90516 – Seakeeper 1 Bolt-In Installation Details
  • 90517 – Seakeeper 1 Installation Fixture Kit
  • 90599 – Seakeeper 1 Bolt-In Kit

Preparation of Vessel Structure

Drawing No. 90559 – Seakeeper 1 Generic Installation Guide, shows various structural arrangements to support the integration of the Seakeeper 1. The Generic Installation Guide offers above and below deck installation arrangements with fiber-reinforced plastic (FRP) and aluminum structures, which should provide solutions for most vessels. Depending on the structure to which the Seakeeper is fastened, blind threaded holes or through-bolting can be utilized. The Seakeeper 1 is affixed to the hull via four bolts in the Seakeeper 1 frame. Each Seakeeper 1 foundation bolt has a vibration isolation assembly to minimize the transmission of vibrations to the hull structure.

Refer to Seakeeper Drawing No. 90516 – Seakeeper 1 Bolt-In Installation Details. This drawing contains critical design dimensions and loads that must be considered in the design of the boat’s structure that will receive the Seakeeper 1. It is assumed that a proper structural analysis has been performed for the vessel structure to which the Seakeeper will be fastened to ensure proper strength margins for the loads the Seakeeper will create during operation.

The vessel structure supporting the Seakeeper should be installed so the Seakeeper is parallel to the waterline in the transverse direction and within 2 degrees longitudinally.

In addition, the four areas on top of the structure on which the Seakeeper 1 will rest need to be co-planar within .06 in. (1.5 mm) to minimize potential distortion of Seakeeper isolation mounts when installed.

Seakeeper offers an installation fixture kit, P/N 90517. The fixture has 4 holes located at the same centers as the mounting holes on the Seakeeper 1. The fixture locates the hole patterns at the proper spacing both in the forward-aft direction and the port-starboard direction. See Figure 5 for more details regarding the Seakeeper 1 template.

Note: Do NOT use the installation fixture to establish the Seakeeper envelope dimensions or clearances. Refer to Drawing No. 90516 – Seakeeper 1 Bolt-In Installation Guide, for envelope dimensions. A 3-D model of the Seakeeper 1 is available on the Seakeeper website to aid in designing the Seakeeper foundation and the space around the Seakeeper.

Figure 5 – Seakeeper 1 Fixture Kit (P/N 90517)

Transfer of Holes to Boat Structure

The following instructions should be used to establish the Seakeeper 1 bolt pattern on the hull structure that has been designed to accept the Seakeeper 1, based on the information provided in Drawing No. 90599 – Seakeeper 1 Bolt-In Kit and Drawing No. 90516 – Seakeeper 1 Bolt-In Installation Details.

  1. Lower installation fixture onto vessel structure.
  2. The four Isolation Mounts, where the Seakeeper 1 contacts the hull structure, must be coplanar to within 0.06 in. (1.5 mm).
  3. Align fixture in desired location and transfer holes from fixture plate to the vessel structure by transfer punch. Note that holes in fixture plate are ø9/16 in. (14.287 mm).
  4. Using the bushings in the fixture holes as a guide to stay perpendicular with the vessel structure, drill 4 X 9/16 in. diameter holes for M14 x 2.0 1.5xDIA (21 mm length minimum) threaded inserts in vessel structure at marked locations to mate with holes in the Seakeeper foundation.
  5. Tap threads in holes for M14 x 2.0 1.5xDIA threaded inserts.
Figure 6 – Stainless Steel Threaded Insert Details
  1. Install threaded inserts into holes using Helicoil installation tool.
  2. Remove threaded insert prongs after threaded inserts are installed.

Installation of Seakeeper

  1. Locate and position the lower snubbing washers onto vessel foundation structure at each of the 4 hole locations.
    1. NOTE: Sealant or caulk is recommended to be applied around the outside edge of the lower face of each lower snubbing washer, where it contacts the vessel structure. This will maintain the position of the snubbing washer and prevent water from wicking between the parts and setting up corrosion.
    2. Sealant is not required between the snubbing washer faces and isolator bushings.
  2. Lower the Seakeeper 1 onto the lower snubbing washer on the vessel structure and align over drilled holes.
Figure 7 – Seakeeper 1 Installation
  1. Using a flexible extendable magnet (McMaster P/N: 3838A42 or similar), install the Seakeeper 1 Bolt-In Kit – P/N 90599: isolator mount sleeve tube, upper snubbing washer, wedge-lock washer, and bolt at each isolation mount.
    1. Figure 8 shows an exploded view of the Bolt-In Kit.
    2. Before installation, apply a moderate coat of anti-seize to the threads of each bolt.
    3. Insert an isolator mount sleeve tube in each of the four vibration isolator assemblies.
    4. The upper snubbing washer, wedge-lock washer, and M14 Bolt can be stacked as one assembly by attaching the magnet to the snubbing washer.

Figure 8 – Seakeeper 1 Bolt Stack Arrangement Exploded (left) / Installed (right) (P/N 90599)
  1. Torque all fasteners to 115 ft-lbs (156 N-m). New bolts must be used for each installation and re-installation.
    1. Threaded inserts can be reused if they are found to be intact and without damage.