2.0 Mechanical Installation

2.1 Mechanical Installation Introduction

The Seakeeper 9 is capable of producing loads up to 3,842 lbs (17.09 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 high 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 9:
1. Bolt-In Installation
2. Bond-In Installation

It is assumed that the installer is familiar with installing mechanical fasteners in marine structures or using high strength adhesives on aluminum and fiberglass (FRP), 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 perform a structural analysis.

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

Reference Documents & Drawings:

• 90225 – Seakeeper 9 Installation Details – Bolt in Method
• 90226 – Seakeeper 9 Installation Details – Bond in Method
• 90253 – Seakeeper 9 Installation Template Kit
• 90384 – Seakeeper 9 Generic Installation Guide
• 90331 – Seakeeper 9 Bolt in Clearances
• 90642 – Seakeeper 9 Bolt-in Kit
• 90643 – Seakeeper 9 Thru-Bolt Kit

2.2 Selection of Installation Location

The Seakeeper should be installed aft of amidships to minimize high acceleration loadings due to hull/wave impacts during operation at high speed or in large waves. If the only possible Seakeeper location is forward of amidships then the installer should have Seakeeper review the installation location prior to finalizing the design.

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 Center of Gravity location, trim, overall stability, and performance of the vessel.

The Installer is solely responsible for ensuring that the Seakeeper is properly located and installed on the vessel foundation with an adequate margin of safety for the specified design loads and vessel operating characteristics.

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

• Adequate service access for scheduled maintenances and overhaul of the Seakeeper 9 is required. See Figure 4 and Drawing No. 90225 – Seakeeper 9 Bolt-In Installation Details for service clearance requirements.
• The Seakeeper should be installed in a dry space to minimize effects of corrosion.
• Clearance for all recommended scheduled maintenance and any repairs that may be necessary (See Figure 3).

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

Figure 3 – Seakeeper 9 Installed Clearance Considerations

Refer to Figure 4 for required clearances to transverse beams. If a transverse beam is located under the forward brace, it must be 1 in. (25 mm) from the edge of the Seakeeper Frame to provide the necessary clearance for the swing of the motor power cable during the Seakeeper’s precession. Clearances aft of the Seakeeper are shown to provide access for regular scheduled maintenance.

2.2.1 Overhead Clearance Considerations

Access above the Seakeeper 9 must be considered for maintenance and service space. Figure 5 shows space considerations around and above Seakeepers installed below deck surface.

2.2.2 Noise/Soundproofing

Seakeeper 9 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 <70 dCB 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 an enclosed space such as a machinery space, lazarette, or bilge. If additional noise reduction is needed, sound proofing insulation can be used in the space around the Seakeeper unit.

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.

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.

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. 90225 – Seakeeper 9 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 recommends a safety factor of 3.0.

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 structure on which the Seakeeper frame 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 9 is mounted to a dissimilar metal structure.

Seakeeper provides an installation template kit, P/N 90253, which contains plates that match the mating surfaces of the four feet located on the Seakeeper’s frame. 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 6 and 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. 90225 – Seakeeper 9 Bolt-In Installation Details, for envelope dimensions. A 3-D model of the Seakeeper is available on the Seakeeper Technical Library (www.seakeeper.com/technical-library/) 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) AS SEEN IN FIGURE 6. REFERENCE SEAKEEPER DRAWING NO. 90225 – SEAKEEPER 9 BOLT-IN INSTALLATION DETAILS.

CAUTION: Tight clearances from cable guide bands to hull structure.
See above figure for dimensions and reference Seakeeper Drawing No. 90225 – Seakeeper 9 Bolt-In Installation Details for complete Seakeeper 9 envelope.

2.4.2 Transfer of Holes to Boat Structure

1. Lower assembled fixture onto hull structure, see Figure 8.
2. The four areas where the feet of the Seakeeper will rest should be coplanar to within .06 in. (1.5mm). See figure below.
3. Align fixture in desired location and transfer holes from fixture plate to the hull structure by transfer punch. Note: Holes in fixture plate are ø 0.55 in. (14 mm).

2.4.3 Bolt-in Installation

Blind-Hole Instructions

1. Remove Template Fixture and drill SIXTEEN (16) 0.571 in. ø (14.5 mm ø) holes perpendicular to the vessel structure to a minimum depth of 0.84 in. (21 mm). Take special care to drill perpendicular to mounting surface.
2. Tap drilled holes for M14-2.0 threaded inserts.
3. Install 16 M14-2.0 x 1.5 in. D (21 mm length) locking threaded inserts into holes in hull structure at drilled and tapped locations using threaded insert manufacturer provided installation tool.
4. Remove threaded insert prong / tag after threaded inserts are installed.

Through-bolt Instructions

Remove Template Fixture and drill sixteen(16) 0.59 IN. (15 mm) ø perpendicular to the vessel structure. Take special care to drill perpendicular to mounting surface. A drill guide is recommended.

2.4.4 Installation of Seakeeper

1. Lower Seakeeper into position onto the hull foundation beams and align over drilled holes. Apply a small bead of marine sealant (e.g., SILI-THANE 803 or equivalent) between mating surfaces of Seakeeper frame and hull structure to prevent moisture wicking into bolt holes.
   
   1. For dissimilar metal foundations, locate and position the 4 isolation gaskets (P/N 10860) onto foundation beams and apply a small bead of marine sealant (e.g., SILI-THANE 803 or equivalent) between both mating surfaces of each isolation gasket where it contacts the beam and Seakeeper.
2. Install Mounting Bolts, as shown in Figure 10:
   
   1. For Blind-Hole installations (P/N 90642 – Seakeeper 9 Bolt-In Installation Kit), install the Seakeeper supplied Grade 10.9, M14-2.0 x 85 mm fasteners or alternative Grade 10.9, M14-2.0 bolts to maintain a minimum thread engagement of 0.90 in. (23 mm). Apply a moderate coat of nickel-based anti-seize (e.g., SAF-T-EZE nickel-based 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.
   2. For Through-Bolt Installations (P/N 90643 – Seakeeper 9 Through-Bolt Installation Kit), install the Seakeeper supplied Grade 10.9, M14-2.0 x 100 mm fasteners or alternative Grade 10.9, M14-2.0 bolts 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-based 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.
3. Torque all fasteners to 100 ft-lbs (135.6 N-m).
   
   1. New bolts, matching the Seakeeper specification, must be used for each installation and reinstallation that meet the requirements listed above.
4. Proceed to electrical and cooling portion of the installation.

2.5.1 Bond-In 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-GripSG300, which provide compatibility with aluminum and FRP substrates, adequate working time, and exceed the strength requirements. See Sheet 6 of Seakeeper Drawing No. 90226 – Seakeeper 9 Bond-In Installation Details for loads information and recommended adhesive properties.

2.5.2 Preparation of Hull Structure

Refer to Seakeeper Drawing No. 90226 – Seakeeper 9 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 Seakeeper loads. A complete bond is required between the inside surface of the saddles and the hull structure. Seakeeper recommends having a minimum of 2.5 L / 0.66 gal of adhesive, on hand for installation. Number of cartridges required is determined by dividing total volume by cartridge volume. There is some adhesive waste as a part of the process so a good rule of thumb is to purchase 50% more adhesive than estimated volume to bond. Depending on conditions and adhesive used, two workers may be required to 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 106 in.² (684 cm²) for a total bonded surface area for all four saddles of 424 in.² (2,736 cm²).

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

Seakeeper provides an installation fixture template, P/N 90253, that locates the saddles at the proper spacing both in the forward-aft direction and the port-starboard direction. See Figures 11 & 12 below, and Figure 13 in the following section. Once assembled with the provided saddle fittings, the fixture can be used to check 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 the 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 recommended range of .04 in. to .13 in. (1 to 3 mm).

Note: Do NOT use the installation fixture to establish Seakeeper envelope dimensions. Refer to Drawing No. 90226 – Seakeeper 9 Bond-In Installation Details, for envelope dimensions. A 3-D model of the Seakeeper is available on the Seakeeper Technical Library (http://www.seakeeper.com/technical-library/) 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. 90226 – SEAKEEPER 9 BOND-IN INSTALLATION DETAILS.

2.5.3 Hull Preparation

1. Position installation fixture (Figure 13) on hull girders noting recommended clearances for maintenance from Figure 4 (in Section: Selection of Installation Location). Check that the screws fastening the saddles to the installation fixture are tight (Figure 14).

2. Mask hull area (Figure 14) around foundation saddles for easy clean-up and to create outline of surface area to receive adhesive as (Figure 13). Ensure that the bond gap is within Seakeeper’s recommended thickness, or 3 mm if using Plexus MA590.

3. Raise fixture clear of foundation. Check all four mounting areas are co-planar to within .13 in. (3 mm) to each other, as well as parallel to the water line plane, as shown in Figure 13 and 15.

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 15.
6. Thoroughly sand girder bond surfaces with 80 grit sandpaper. (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.

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 14).
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 16. Do not remove these screws.

3. Thoroughly sand all saddle inside surfaces with 80 grit sandpaper in cross-hatch pattern. (IMPORTANT – BOND STRENGTH MAY BE REDUCED IF THIS STEP IS SKIPPED.)
4. Thoroughly clean with alcohol or acetone the inside surfaces of Seakeeper foundation saddles to remove any contaminates as shown in Figure 16. Use new paper towels for cleaning, 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: This is a sample if using Plexus, if using another adhesive follow manufacturer’s recommendations.

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 figure to the right. Apply approximately ½ to ⅔ cartridges (200 – 275 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 7). 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 of the four saddles. Follow the numbered sequence shown below 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. When gaps of all four saddles have been completely filled, clean off excess adhesive, remove plugs, and remove masking tape.
10. Allow adhesive to cure per manufacturer’s recommendations. Follow adhesive guidelines for curing time versus temperature prior to removing the fixture.
11. 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 to the right.
2. Rig Seakeeper for lifting and lower it 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 the Seakeeper foundation frame to saddles.
4. Install Seakeeper supplied Grade 8.8, M14-2.0 x 85 mm fasteners or alternative Grade M10.9, M14-2.0 bolts to maintain a minimum thread engagement of .084 in. (21 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.
5. Torque all fasteners to 100 ft-lbs (136 N-m).
   
   1. New bolts, matching the Seakeeper specification, must be used for each installation and reinstallation that meet the requirements listed above.
6. Proceed to electrical and cooling portion of the installation.