2.0 Mechanical Installation

2.1 Mechanical Installation Introduction

The Seakeeper 6 is capable of producing loads up to 3820 lbs (17 kN) at each of the four mounts. These forces should be considered to be acting simultaneously, fully reversing, and will repeat an infinite number of times. Careful consideration should be given to foundation design to ensure it is capable of transferring these loads into the hull. These loads do NOT include vessel motion accelerations, such as vertical slam loads which can be significant for higher speed vessels. The responsible party for designing the supporting structure (boat builder, installer, or hired sub-contractor) must accommodate the above forces plus a reasonable factor of safety. Seakeeper recommends a minimum safety factor of 3.0 (yielding a Safety Margin of 2.0).

There are two methods of installing the Seakeeper 6:
1. Bolt-In Installation
2. Saddle Installation

It is assumed that the installer is familiar with bonding using high strength adhesives or mechanical fasteners to marine structures and has performed structural analysis to assure the structure to which the Seakeeper mounts can properly transfer the loads the Seakeeper creates into the hull structure. If the installer has any doubt about the ability of the structure to transfer the loads to the hull then a licensed naval architect or marine engineer should be contacted to do a structural analysis.

The installer should review the following list of reference drawings to ensure the installation procedure is fully understood.

Reference Documents & Drawings:

• 90392 – Seakeeper 6 / 5 Installation Fixture Kit
• 90398 – Seakeeper 6 / 5 Bolt-In Installation Details
• 90399 – Seakeeper 6 / 5 Bond-In Installation Details
• 90400 – Seakeeper 6 / 5 Bolt-In Kit
• 90660 – Seakeeper 6 / 5 Thru-Bolt Kit
• 90401 – Seakeeper 6 / 5 Bond-In Saddle Kit
• 90448 – Seakeeper 6 / 5 Generic Installation Guide

2.2 Selection of Installation Location

Seakeeper can only assess installation location regarding its impact on Seakeeper operation and serviceability. Seakeeper cannot determine how the installation location will affect the vessel static or directional stability other than cyclic roll reduction. The Installer is responsible for considering the Seakeeper‘s effect on the CG location, trim, overall stability, and performance of the vessel.

Selection of mounting location of Seakeeper should consider the following desirable features:

1. Overhead access or sufficient clearance for removal / re-installation of the Seakeeper for overhaul in future years. Provide adequate clearance for maintenance, as shown in Figure 1 and 2 below.
2. The Seakeeper should be installed in a dry space to minimize effects of corrosion.
3. Installed near vessel’s longitudinal center of gravity (LCG) to minimize effects on trim and performance in various loading conditions.

VIEWS SHOWING RECOMMENDED CLEARANCES AROUND THE SEAKEEPER FOR USE OF HANDTOOLS, EASE OF MAINTENANCE, INSTALLATION, AND PROPER OPERATION.

Figure 1 – Seakeeper 6 Installed Clearance Considerations

Refer to Figure 2 for recommended clearances to transverse beams. If a transverse beam is located under the forward brace, it must be 4 in. (102 mm) from the edge of the saddle beams to provide the necessary clearance for the swing of the motor power cable during precession. Clearances aft of the Seakeeper are shown to provide access for maintenance.

2.2.1 Noise/Soundproofing

Seakeeper noise has been measured under steady state conditions (no wave load) in Seakeeper‘s Engineering Lab and in our Factory Demo Boat. The steady state noise is typically <72 dBC at 1 meter. As the frequencies emitting the highest sound pressures are low (like other marine machinery), it is recommended that the Seakeeper be installed in a machinery space that is already treated with soundproofing.

2.3 Selection of Installation Method

The Seakeeper 6 can be affixed to the hull structure using two methods:

1) Bolt-In installation
2) Saddle installation

See figures below.

Option 1 would be applied when a metal structure is available for attachment. The foundation would fasten directly to hull structure using isolation gaskets and sixteen M12-1.75 fasteners. Depending on the structure to which the Seakeeper is fastened, blind threaded holes or thru-bolting can be utilized.

Option 2 would be most commonly used on a hull constructed of glass reinforced plastic (GRP) or fiberglass. For this option, four 7.5 in. (191 mm) long by 3.38 in. (85.7 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 very important.

2.4.1 Preparation of Vessel Structure

Seakeeper provided mounting hardware is intended to apply to typical installation arrangements. However, each installation, especially custom aftermarket foundations, should be thoroughly reviewed to ensure the provided hardware meets the required thread engagement for the Seakeeper unit being installed. The mounting bolt thread engagement requirements are outlined in the Installation Manuals and Installation Details Drawings for each Seakeeper model. This also applies to Seakeeper model adapter kits and OEM built frames where the bolt hole depth should be checked to ensure the bolts will not bottom, preventing the bolts from achieving the intended preload.

The Seakeeper supporting structure should be parallel to the vessel waterline, with up to 2 degrees allowance for trim.

In addition, the four areas on top of the beams on which the feet of the Seakeeper foundation and isolation gaskets will rest need to be co-planar within .06 in. (1.5 mm) to minimize potential distortion of Seakeeper support frame when installed. The isolation gaskets are only used when the Seakeeper 6 is mounted to a dissimilar metal structure.

When the Seakeeper provided hardware is not appropriate, the bolt specification (diameter and thread pitch) and grade should be matched in the required length and used with the Seakeeper provided washers. Mounting bolts should always be torqued to the Seakeeper specification. All Seakeeper provided bolts are metric course thread. Hardware specifications are also listed in the Installation Manuals and Installation Details Drawings.

Refer to Seakeeper Drawing No. 90398 – Seakeeper 5/6 Bolt-In Installation Details. Important dimensional and load information is given in this drawing that will impact the design details of the structure that will receive the Seakeeper. It is assumed that a proper structural analysis has been performed for the hull structure to which the Seakeeper will be fastened to ensure proper strength margins for the loads the Seakeeper will create during operation.

Seakeeper provides an installation template kit, P/N 90392, which contains four plates that mimic the mating surfaces of the four feet located on the Seakeeper’s foundation. These plates have 4 holes located at the same centers as the mounting holes on the Seakeeper. The fixture locates the hole patterns at the proper spacing both in the forward-aft direction and the port-starboard direction. See Figure 5 below. Once assembled, the fixture can be used to check clearances and alignment of the hull structure.

Note: Do NOT use the installation fixture to establish Seakeeper envelope dimensions. Refer to Drawing No. 90398 – Seakeeper 6 Bolt-In Installation Details, for envelope dimensions. A 3-D model of the Seakeeper is available on the Seakeeper website (www.seakeeper.com) to aid in designing the Seakeeper foundation and the space around the Seakeeper.

NOTE: MAKE SURE NO OBSTRUCTIONS FROM THE HULL STRUCTURE CAN BE SEEN WITHIN THE INSIDE OF THE INSTALLATION TEMPLATE KIT (INSIDE THE MARKED RED LINES). REFERENCE SEAKEEPER DRAWING NO. 90398 – SEAKEEPER 6 BOLT-IN INSTALLATION DETAILS.

CAUTION: Tight clearances from cable guide bands and brake side gimbal shaft to hull structure. See below for brake side gimbal shaft clearance. See above figure for dimensions and reference Seakeeper Drawing No. 90398 – Seakeeper 6 Bolt-In Installation Details, for complete Seakeeper envelope.

2.4.2 Transfer of Holes to Boat Structure

1. Lower assembled fixture onto hull structure.
2. The four areas where the feet of the Seakeeper will rest should be coplanar to within .06 in. (1.5 mm). See figure below.
3. Align fixture in desired location and transfer holes from fixture plate to the foundation structure. Note that holes in fixture plate are ø0.487 in. (12 mm). A transfer punch is supplied with installation template kit, P/N 90392.

Figure 8 – Bolt-In Hole Transfer Fixture

2.4.2.1 Blind Hole Installation

1. Remove Template Fixture and drill sixteen(16) 0.49 in. (12.5 mm) holes perpendicular to the vessel structure to a minimum depth of 0.94 in. (24 mm). Take special care to drill perpendicular to mounting surface. A drill guide is recommended. Remove any impeding obstructions.
2. Tap drilled holes for helical thread inserts per documentation accompanying helical threaded inserts.
3. Install sixteen (16) M12-1.75 X 18 mm threaded inserts into holes in hull structure at drilled and tapped locations using threaded insert manufacturer provided installation tool.
4. Remove threaded insert prong / tang after threaded inserts are installed.

2.4.2.2 Through-Bolt Installation

1. Remove Template Fixture and drill sixteen (16) 0.512 in. (13 mm) ø holes perpendicular to the vessel structure. Take special care to drill perpendicular to mounting surface. A drill guide is recommended.

2.4.3 Installation of Seakeeper

1. Locate and position four foundation spacers (P/N 11241) onto hull structure.
   
   1. For dissimilar metal foundations, locate and position four isolation gaskets (P/N 11145) onto foundation beams and apply a small bead of marine sealant (SILI-THANE 803 or equivalent) between both mating surfaces of each isolation gasket where it contacts the beam and the Seakeeper.
2. Lower Seakeeper into position onto foundation beams and align over drilled holes.
3. Install Mounting Bolts:
   
   1. For Blind-Hole installations (P/N 90400 – Seakeeper 6 / 5 Bolt-In Kit), install the Seakeeper supplied M12-1.75 fasteners to maintain a minimum thread engagement of 0.71 in. (18 mm). Apply a moderate coat of nickel-based anti-seize (e.g., SAF-T-EZE nickel grade anti-seize, SBT-4N or equivalent) to the threads of each bolt and include a small bead of marine grade sealant (e.g., SILI-THANE 803 or equivalent) under each bolt head and washer before installation. See Figure 11.
   2. For Through-Bolt installations (P/N 90660 – Seakeeper 6 / 5 Through-Bolt Kit), install the Seakeeper supplied M12-1.75 fasteners to maintain a minimum of 2 threads protruding past nut. Apply a moderate coat of nickel-based anti-seize (e.g., SAF-T-EZE nickel grade anti-seize, SBT-4N or equivalent) to the threads of each bolt and include a small bead of marine grade sealant (e.g., SILI-THANE 803 or equivalent) under each bolt head and washer before installation. See Figure 12.
4. Torque all fasteners to 95 ft-lbs (129 N-m).
   
   1. New bolts, matching the Seakeeper specification, must be used for each installation and reinstallation that meet the requirements listed above.
5. Proceed to electrical and cooling portion of the installation.

2.5.1 Saddle Installation Introduction

Seakeeper recommended adhesives are listed in TB-90382 – Structural Adhesives Recommendations. 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 when selecting the appropriate adhesive, such as working time, material compatibility, and surface preparation are three important factors to consider. Proper surface preparation in accordance with the adhesive manufacturer’s recommendations prior to installation is critically important. Information regarding pot-life, structural properties and material compatibility can be found on the adhesive product’s technical data sheet (TDS). An etching/cleaning primer compatible with the adhesive should be used on all aluminum surfaces if recommended by the manufacturer. Typically, two-part methacrylate based adhesives are the best options for bond-in installations such as Plexus MA590 and Sci-Grip SG300, which provide compatibility with aluminum and FRP substrates, adequate working time, and exceed the strength requirements. See Sheet 5 of Seakeeper Drawing No. 90399 – Seakeeper 5/6 Bond-In Installation Details, for loads information and recommended adhesive properties.

2.5.2 Preparation of Hull Structure

Refer to Seakeeper Drawing No. 90399 – Seakeeper 5/6 Bond-In Installation Details. Important dimensional and load information is given in this drawing that will impact the design details of the structure that will receive the Seakeeper as well as selection of the adhesive to bond the Seakeeper into the hull.

The foundation “saddles” of the Seakeeper are designed to be bonded directly to the composite hull structure of the vessel to effectively distribute gyroscopic loads. Complete coverage of the saddles and the hull structure surfaces is required for bond-in installations. Seakeeper recommends having a minimum of 1.6 L / 0.41 gal of adhesive, on hand for installation. Number of cartridges required is determined by dividing total volume by cartridge volume. Some adhesives require etching primer for aluminum surfaces (Plexus MA590 requires PC120 primer). Both manual and pneumatic application guns are available from adhesive manufacturers. Two workers should apply the adhesive at the same time to finish the installation before the adhesive starts to cure. To aid in determining the quantity of adhesive required, the interior surface area (bonding surfaces) of each saddle is 58.2 in.² (375 cm²) for a total bonded surface area for all four saddles of 232.5 in.² (1500 cm²).

The hull structure supporting the Seakeeper should be installed so the Seakeeper is parallel to the waterline. The four areas on top of the beams that the saddles will bond to need to be co-planar within .13 in. (3 mm) for consistent adhesive bond gap. In addition, the four areas on top of the saddles on which the feet of the Seakeeper foundation will rest need to be co-planar within .06 in. (1.5 mm) to minimize potential distortion of Seakeeper support frame when installed.

Note that any paint or gel-coat present in bond area should be removed so that adhesive will bond directly to laminate fibers and resin. Fiberglass and aluminum surfaces should be sanded in a cross-hatch pattern with 80 grit sandpaper and thoroughly cleaned prior to adhesive application.

Seakeeper provides an installation fixture template, P/N 90392, that locates the saddles at the proper spacing both in the forward-aft direction and the port-starboard direction. See Figures 13 & 14 below. Once assembled with the provided saddle fittings, the fixture can be used to check saddle clearances and alignment of the hull structure. The fixture will allow the builder / installer to lay-up and adjust the foundation dimensions to create a low-clearance fit between the Seakeeper foundation saddles and the hull structure. Shear strength of the adhesive will be maximized if the cured thickness between the vessel structure and Seakeeper saddles is at the thinner end of the adhesive manufacturer’s recommended range. Therefore, the fixture should be used to confirm that the overall dimensions of the foundations are square and level and that the adhesive gap is within Seakeeper’s maximum recommended thickness of .13 in. or 3 mm.

Note: Do NOT use the installation fixture to establish Seakeeper envelope dimensions. Refer to Drawing No. 90399 – Seakeeper 5/6 Bond-In Installation Details, for envelope dimensions. A 3-D model of the Seakeeper is available on the Seakeeper website (www.seakeeper.com) to aid in designing the Seakeeper foundation and the space around the Seakeeper.

NOTE: MAKE SURE NO OBSTRUCTIONS FROM THE HULL STRUCTURE CAN BE SEEN WITHIN THE INSIDE OF THE INSTALLATION TEMPLATE KIT (INSIDE THE MARKED RED LINES). SEE DRAWING NO. 90399 – SEAKEEPER 5/6 BOND-IN INSTALLATION DETAILS.

2.5.3 Fiberglass Hull Preparation

1. Position installation fixture (Figure 15) on hull girders noting recommended clearances for maintenance from Figure 2 (in Section: Selection of Installation Location). Check that the screws fastening the saddles to the installation fixture are tight (Figure 13).

2. Mask hull area (Figure 16) around foundation saddles for easy clean-up and to create outline of surface area to receive adhesive (Figure 15). 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 .06 in. (1.5 mm) to each other, as well as parallel to the water line plane, as shown in Figure 17.

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 as shown in Figure 13.
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.

2.5.4 Seakeeper Saddle Preparation

1. Ensure that screws fastening saddles to the installation fixture are tight (Figure 13).
2. Check that each saddle contains 2 plastic screws which will ensure an adhesive gap of .080 in. (2 mm) on top surface of hull as shown in Figure 18.

3. Thoroughly sand all saddle inside surfaces with 80 grit sandpaper. (IMPORTANT – BOND STRENGTH MAY
BE REDUCED IF THIS STEP IS SKIPPED.)

4. Wipe surfaces clean from dust with alcohol or acetone using new paper towels, not shop rags.

5. If using Plexus MA590 adhesive, apply Plexus PC-120 surface conditioner to inside surfaces of Seakeeper
foundation saddles in accordance with manufacturer instructions. These instructions are located at the end
of this section. If using an alternate adhesive, check with manufacturer if any surface conditioner/etch is
required for the aluminum saddles.

2.5.5 Bonding Saddles to Hull

Note: If using Plexus MA590 adhesive, the Seakeeper saddles should be installed when PC-120 is confirmed dry.

1. Assemble Plexus cartridge into either the manual or pneumatic gun as shown. Remove cap on cartridge and attach mixing tip. For pneumatic gun, start with low air pressure and increase until desired flow rate is achieved.

2. Cut tip of mixing wand as shown in photo below.

3. Prepare a second mixing wand as shown in photo below by attaching the simple flexible nozzle to the end of the mixing tip. Set aside for now as this will be used to inject adhesive into the sides of each saddle after the fixture / saddles are in position.

4. Install provided rubber plugs in six holes of each saddle. The plugs will limit the adhesive being forced out of the injection holes in step 6 below.

5. Apply large bead of Plexus adhesive to the hull structure as shown in the image below. Apply approximately 1/3 to 1/2 of a cartridge (150 – 200 mL) at each of the four locations. Work deliberate and fast as it takes some time to apply the adhesive to the structure. MA590 has a 90-minute working time at room temperature (73°F / 23°C). This working time can reduce to 40-50 minutes at elevated temperatures. Two workers should apply the adhesive at the same time to finish the installation before the adhesive starts to cure.

6. Lower fixture and saddles over the hull structure and apply light downward pressure to each of the four saddles until the two nylon screws rest on the hull structure (see Figure 12). The adhesive will be forced towards the forward and aft ends of each saddle and partially down the sides of the foundation beams.
7. Insert full adhesive cartridge along with mixing wand / nozzle assembled in Step 3 above into gun.
8. Begin to inject adhesive into the six holes provided on each side of each of the four saddles. Follow the numbered sequence shown until the adhesive pushes out the edges of the saddle perimeter. The intent is to pump in the adhesive working from the top down and from the middle to the ends to fill the gaps and displace any air.

A complete bond is required – excess adhesive will be needed to make sure all bond gaps are filled.

9. Repeat above steps on both sides of all four saddles.
10. When gaps have been completely filled, clean off excess adhesive, remove plugs, and remove masking tape.
11. Allow adhesive to cure per manufacturer’s recommendations. Follow adhesive guidelines for curing time versus temperature prior to removing the fixture.
12. Bonding of Seakeeper saddles onto the hull is now complete. Remove installation fixture.

2.5.6 Installation of Seakeeper

1. The four areas where the feet of the Seakeeper will rest should be coplanar to within .06 in. (1.5 mm). See figure below.
   
   NOTE: DO NOT INSTALL SEAKEEPER WITH 1/2 IN. SPACERS WITH SADDLE KIT.
2. Rig Seakeeper for lifting and lower into position onto top surface of four saddles.
3. Apply a small bead (approximately 4 mm wide) of sealant or caulk to the mating surfaces between the saddles and the Seakeeper foundation. Adjust position of Seakeeper until alignment is achieved for the 16 fasteners that will attach Seakeeper foundation frame to saddles.
4. Install Seakeeper supplied M12-1.75 X 65 mm fasteners – apply a moderate coat of removable thread locker to the threads of each bolt and include a small bead of sealant under each washer before installation.
5. Torque all fasteners to 65 ft-lbs (88 N-m).
6. Proceed to electrical and cooling portion of the installation.