2.0 Mechanical Installation

2.1 Mechanical Installation Introduction

The Seakeeper can produce loads up to 11,381 lbs (50.6 kN) at each of the four mounts and careful consideration should be given to foundation design to ensure it can transfer these loads into the hull. These loads do NOT include vessel motion accelerations, such as vertical slam loads which can be significant for high 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).” The Seakeeper 40 FRB supports Bolt-In and Bond-In Installation methods.

It is assumed that the installer is familiar with 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:

• 90713 – Seakeeper 40 Bolt-In Clearances
• 90714 – Seakeeper 40 Bolt-In Installation Details
• 90878 – Seakeeper 40 Bond-In Installation Details
• 90088 – Bond-In Installation Fixture Kit
• 90089 – Seakeeper 40 Bolt-In Installation Fixture Kit
• 90614 – Seakeeper 40 Bolt In Kit (Optional)
• 90086 – Seakeeper 40 Thru-Bolt Kit (Standard)
• 90287 – Seakeeper Bond-In Saddle Kit
• TB-90382 – Structural Adhesive Recommendation

2.2 Selection of Installation Location

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

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 installation 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 CG 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 of the Seakeeper should consider the following desirable features:

• Overhead access or sufficient clearance for removal / re-installation of the Seakeeper for overhaul in future years per Figure 3.
• The Seakeeper should be installed in a dry space to minimize effects of corrosion.
• Clearance for replacement of gimbal angle sensor on gimbal shaft (see Figure 3).
• Clearance for filling / purging brake hydraulic oil (see Figure 3).
• Clearance for filling water/glycol cooling circuit (see Figure 3).
• Clearance for replacement of brake hydraulic cylinders (see Figure 3).

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

Figure 3 – Seakeeper 40 Installed Clearance Considerations
6 in. (152 mm) on each side with one side having 28 in. (711 mm)
12.6 in. (320 mm) overhead service clearance

2.2.1 Noise/Soundproofing

Seakeeper noise has been measured under steady state conditions (no wave load) in Seakeeper‘s Engineering Lab. The steady state noise is typically < 73 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 40 FRB can be affixed to the hull structure using two methods 1) Bolt-In installation or 2) Bond-In (Saddle) installation. See figures below.

Option 1 would be applied when a metal structure or laminated metal plates are available for attachment. The foundation would fasten directly to the hull structure or plates using isolation gaskets for metal-to-metal contact using 32 x M16-1.0 fasteners. Depending on the structure to which the Seakeeper is fastened, blind threaded holes (Seakeeper Part No. 90614) or thru-bolting (Seakeeper Part No. 90086) can be utilized.

Option 2 would be commonly used on a hull constructed of glass-reinforced plastic (GRP) or fiberglass. For this option, four 16.0 in. (406 mm) long by 8.0 in. (203 mm) deep saddles (Seakeeper Part No. 90287) 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, such as Plexus MA590. 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 critical factors. Proper surface preparation per the adhesive manufacturer’s recommendations before installation is required.

Note: If bonding saddles to a metal structure, contact Seakeeper for hull preparation instructions.

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. 90714 – Seakeeper 40 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.

The hull structure supporting the Seakeeper should be arranged so the Seakeeper is parallel to the waterline in the forward-aft and port-starboard directions (with up to 2° allowance for trim). In addition, the four areas on top of the beams on which the isolation mounts will rest, need to be co-planar within 0.13 in. (3 mm) to minimize potential distortion of Seakeeper support frame when installed.

Seakeeper provides an installation fixture assembly (P/N 90089), which contains four plates that mimic the mating surfaces of the four isolation mounts located on the Seakeeper’s foundation. These plates have 8 holes located at the same centers as the holes in the isolation mounts. These smaller holes can be used to locate the holes in the ship’s structure through use of a transfer punch or drill. The fixture locates the hole patterns at the proper spacing, both in the fore-aft direction and the port-starboard direction. See Figures 4 & 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. 90714 – Seakeeper 40 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.

CAUTION: Tight clearances from cable guide bands to hull structure. See above figure for dimensions and reference Seakeeper Drawing No. 90714 – Seakeeper 40 Bolt-In Installation Details, for complete envelope.

2.4.2 Transfer of Holes to Boat Structure

1. Lower assembled fixture onto hull structure.
2. The four areas where the isolation mounts will rest should be coplanar to within 0.13 in. (3 mm). See figure below. Do not use the fixture to check co-planarity as it is not stiff enough.
3. Align fixture in desired location and transfer holes from fixture plate to the hull structure. A transfer punch is recommended for this step. Note that holes in fixture plate are 0.257 in. (6.5 mm) in diameter.
4. Remove fixture and drill holes in hull structure at marked locations to mate with holes in Seakeeper isolation mounts. A 0.689 in. (17.5 mm) diameter hole is recommended for the provided M16 fasteners.

NOTE: Certain foundation designs that employ threaded blind holes in thick plates may require the installer to obtain alternate fasteners.

2.4.3 Installation of Seakeeper

1. Locate and position 4 isolation gaskets (P/N 10534) onto foundation beams (for metal to metal contacts only).
   NOTE: A FILM OF SEALANT SHOULD BE APPLIED TO THE GASKET TO KEEP WATER FROM WICKING INTO THE JOINT.
2. Lower Seakeeper into position onto foundation beams and align over drilled holes.
3. Install Mounting Bolts:
   
   1. For Through-Bolt installations (P/N 90086 – Seakeeper 40 Thru-Bolt Kit), install the Seakeeper supplied M16-2.0 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 6.
   2. For Blind-Hole installations (P/N 90614 – Seakeeper 40 Bolt-In Kit), install the Seakeeper supplied M16-2.0 fasteners to maintain a minimum thread engagement of 0.95 in. (24 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 7.
4. 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.
5. Proceed to electrical and cooling portion of the installation.

2.5.1 Preparation of Vessel Structure

Refer to Seakeeper Drawing No. 90878 – Seakeeper 40 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. Reference TB-90382 – Structural Adhesive Recommendation for the recommended adhesives for bond-in installation.

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. An estimate of adhesive volume required should be calculated for each installation based on gaps between saddles and structural members. 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 ensure a complete 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 325 in.² (2,097 cm²) for a total bonded surface area for all four saddles of 1,300 in.² (8,387 cm²).

The hull structure supporting the Seakeeper should be arranged so the Seakeeper is parallel to the waterline. In addition, the four areas on top of the beams that the saddles will bond to need to be co-planar within 0.13 in. (3 mm) to minimize potential distortion of Seakeeper support frame when installed, as shown in Figure 13.

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 90088), that locates the saddles at the proper spacing both in the forward-aft direction and the port-starboard direction. See Figures 8, 9, and 10 below. 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 0.04 in. to 0.13 in. (1 to 3 mm).

Note: Do NOT use the installation fixture to establish Seakeeper envelope dimensions. Refer to Drawing No. 90878 – Seakeeper 40 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.

Hull Preparation

1. Position installation fixture (Figure 11) on hull girders noting recommended clearances for maintenance from Drawing No. 90878 – Seakeeper 40 Bond-In Installation Details. Check that the screws fastening the saddles to the installation fixture are tight (Figure 9).

2. Mask hull area (as shown in blue, Figure 12) around foundation saddles for easy clean-up and to create an outline of surface area to receive adhesive, as shown in brown (Figure 13). Ensure that the bond gap is within adhesive manufacturer’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 0.13 in. (3 mm) to each other, as well as parallel to the water line plane, as shown in Figure 13.

4. Thoroughly clean with alcohol or acetone all areas (highlighted in brown, Figure 13) 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. (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.
9. Lift installation fixture clear of foundation. Apply Seakeeper provided adhesive backed foam strips at the eight locations shown (each end of four saddles) in Figure 14 below. These strips are to serve as a dam to minimize adhesive escaping out the ends of the saddles as they are positioned over the bond area.

Note: If bonding saddles to a metal structure, contact Seakeeper for hull preparation instructions.

2.5.2 Bonding Saddles to Hull

Seakeeper Saddle Preparation

1. Ensure that screws fastening saddles to the installation fixture are tight.
2. Check that each saddle contains 4 plastic screws which will ensure an adhesive gap of 0.080 in. (2 mm) on top surface of hull as shown in Figure 15. Do not remove these screws.
3. Thoroughly clean with alcohol or acetone the inside surfaces of Seakeeper foundation saddles to remove any contaminates as shown in Figure 15. Use new paper towels for cleaning, not shop rags.

4. Thoroughly sand all saddle inside surfaces with 80 grit sandpaper. (IMPORTANT – BOND STRENGTH MAY BE REDUCED IF THIS STEP IS SKIPPED.)
5. Wipe surfaces clean from dust with alcohol or acetone using new paper towels, not shop rags.
6. 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.

Bonding Saddles to the 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 adhesive 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 12 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 adhesive to the hull structure as shown in the figure below. Apply approximately 1½ cartridges at each of the four locations. Work deliberate and fast as it takes some time to apply the adhesive to the structure. These working times can be reduced at elevated temperatures. Two workers should apply the adhesive at the same time to finish the installation before the adhesive starts to cure.
   See TB-90382 – Structural Adhesive Recommendation for more details.
   
   • MA590 has a working time of 90 minutes.
   • SciGrip SG300-40 has a working time of 35 to 45 minutes.
   • Pro-Set ADV-176/ADV-276 has a working time of 90 minutes

6. Lower fixture and saddles over the hull structure and apply light downward pressure to each of the four saddles until the four nylon screws rest on the hull structure. 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 step for remaining 7 sides of the saddles.
10. When gaps have been completely filled, clean off excess adhesive, remove foam tape, 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.

2.5.3 Installation of Seakeeper

1. Rig Seakeeper for lifting and lower it into position onto top surface of four saddles.
2. 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 the Seakeeper until alignment is achieved for the 32 fasteners that will attach the foundation frame to saddles. (Note: isolation gasket used for bolt-in installation is not required).
3. Install Seakeeper supplied M16 fasteners as shown in figure below – apply a moderate coat of nickel based anti-seize compound to the threads of each bolt prior to installation and a small amount of marine sealant (Sili-Thane 803 or similar) to the washer faces.
4. Torque all fasteners to 100 ft-lbs (136 N-m).
5. Proceed to electrical and cooling portion of the installation.