Seakeeper 26 User manual

Rev 7 MAR 2021
INSTALLATION MANUAL
*THIS MANUAL ALSO COVERS THE SEAKEEPER 20HD*

INSTALLATION
MANUAL
Product:
Document #:
Rev:
SEAKEEPER 26 / 20HD
90265
7
SEAKEEPER 26 / 20HD
INSTALLATION MANUAL
MARCH 2021
Contents:
Section 1 –Mechanical Installation &PC-120 Guide
Section 2 –Electrical Installation
Section 3 –Cooling Installation
Section 4 –Installation Supplies & Tools
Section 5 –Installation Checklist
45310 ABELL HOUSE LANE, SUITE 350
CALIFORNIA, MD 20619, U.S.A.
PHONE: [phone]
FAX: [phone]
E-MAIL: [e-mail]

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Section 1: MECHANICAL INSTALLATION
1.0 Introduction
This document is intended to give details and guidance to a boat builder or equipment installer to
install the Seakeeper 26. The Seakeeper can produce loads up to 35.89 KN (8,070 lbs.) 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 performance vessels.
There are two methods of installing the Seakeeper 26:
1) Bolt-In Installation
2) Bond-In (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 he should contact a licensed naval architect
or marine engineer to do a structural analysis.
The installer should review the following list of reference drawings to ensure the installation
procedure is fully understood.
Reference Drawings
•90244 Seakeeper 26 Hardware Scope of Supply
•90416 Seakeeper 20HD Hardware Scope of Supply
•90271 Seakeeper 26/20HD Installation Details –Bolt in Method
•90272 Seakeeper 26/20HD Installation Details –Bond in Method
•90085 Seakeeper 26/20HD Bond-in Saddle Kit
•90086 Seakeeper 26/20HD Bolt-In Installation Kit, M16, Through-Bolt
•90614 Seakeeper 26/20HD Bolt-In Installation Kit, M16, Blind-Hole
•90088 Seakeeper 26/20HD Bond-In Installation Fixture Kit
•90089 Seakeeper 26/20HD Bolt-In Installation Fixture Kit
•90310 Seakeeper 26/20HD Cable Block Diagram
•90320 Seakeeper 26/20HD Cooling Water Schematic
FIGURE 1 –SEAKEEPER 26

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Section 1: MECHANICAL INSTALLATION
1.1 Precautions
•The Seakeeper must only be lifted from the supplied lifting eyes (See Section 1.4).
•The Seakeeper flywheel is supported by precision bearings. Make certain while
unpacking and lifting the Seakeeper assembly to NOT drop or impart mechanical shock
as damage to bearings could result.
•While handling / installing the Seakeeper assembly, protect exposed hydraulic brake
cylinder rods (See Figure 1) from scratches or damage as this could lead to premature
seal failure and oil leaks.
•While handling / installing the Seakeeper assembly, do not allow electrical fittings that exit
bottom of enclosure to come in contact with any surface or object as this could damage
the fittings and potentially affect the vacuum integrity of the enclosure.
•Exercise care to protect painted finish as damage to finish could lead to early appearance
degradation of the installed Seakeeper.
1.2 Selection of Seakeeper 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 Seakeeper location
is forward of amidships then the installer should have Seakeeper
review the installation location prior to finalizing the design.
•Overhead access or sufficient clearance for removal / re-installation of the
Seakeeper for overhaul in future years.
•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 2).
•Clearance for filling / purging brake hydraulic oil (see Figure 2).
•Clearance for filling water/glycol cooling circuit (see Figure 2).
•Clearance for replacement of brake hydraulic cylinders (see Figure 2).

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Section 1: MECHANICAL INSTALLATION
VIEWS SHOWING RECOMMENDED CLEARANCES AROUND THE SEAKEEPER FOR USE OF HAND TOOLS,
EASE OF MAINTENANCE, INSTALLATION, AND PROPER OPERATION
FIGURE 2 –INSTALLED SEAKEEPER CLEARANCE CONSIDERATIONS

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Section 1: MECHANICAL INSTALLATION
Safety
There is a large torque about the gimbal axis when the Seakeeper is
precessing. Seakeeper cover panels are provided to prevent personnel or
equipment from contacting the Seakeeper while it is in operation. These covers
should not be stepped on or have anything placed on top. The covers should
always be in place during operation. If it is ever necessary to access the Seakeeper
while the flywheel is spinning, the Seakeeper must be locked at the display to stop
the Seakeeper from precessing. Seakeeper regular maintenance should not be
attempted unless the Seakeeper is locked and the flywheel has stopped spinning.
The Seakeeper should be treated with the same respect one gives a high-speed
rotating propeller shaft or engine shaft.
Noise/Soundproofing
Seakeeper noise has been measured under steady state conditions (no wave load) in
Seakeeper's lab. The steady state noise is typically in the range of 70-75 dB un-weighted. 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.

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Section 1: MECHANICAL INSTALLATION
1.3 Selection of Installation Method
The Seakeeper 26 can be affixed to the hull structure using two methods shown below:
1) Bolt-In Installation
2) Bond-In (Saddle) Installation
OPTION 1 - DIRECT FASTENING OF SEAKEEPER FOUNDATION TO SHIPS STRUCTURE
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 either M16 or 5/8” fasteners.
Depending on the structure to which the Seakeeper is fastened, blind threaded holes or thru-
bolting can be utilized.
OPTION 2 - SADDLE INSTALLATION (4 PLACES)
Option 2 would be commonly used on a hull constructed of glass reinforced plastic (GRP) or
fiberglass. For this option, four 16 inch (406 mm) long by 8 inch (203 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 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 important factors to consider.
Proper surface preparation in accordance with adhesive manufacturer’s recommendations prior
to installation is required.

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Section 1: MECHANICAL INSTALLATION
1.4 Unpacking Crate
1) Reference Seakeeper Drawing No. 90244 Seakeeper 26 Hardware Scope of Supply and
90416 Seakeeper 20HD Hardware Scope of Supply for items that ship with the
corresponding Seakeeper model.
2) Remove electrical components, cables, and misc. items and set aside.
3) Remove packing materials that secure Seakeeper assembly inside the crate.
4) Remove top and angled face cover panels to access lifting eyes.
5) Attach spreader bar to the two lifting eyes located on the top of the Seakeeper enclosure.
Stay clear of any other parts on the Seakeeper. See Figure 3 below.
6) The Seakeeper 26 weighs 1431 kg (3155 lbs).
FIGURE 4 –LIFTING ARRANGEMENT
Spreader Bar
Lifting Eyes

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Section 1: MECHANICAL INSTALLATION
1.5 Bolt-In Installation
1.5.1 Check and Preparation of Hull Structure
Refer to Seakeeper Drawing No. 90271, Seakeeper 26/20HD Installation Details –Bolt in
Method. 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.
Two bolt-in kits are available:
1) Through-Bolt, reference drawing 90086
2) Blind-Hole, reference drawing 90614
The hull structure supporting the Seakeeper should be installed so the Seakeeper is parallel to
the water plane in the port/starboard and forward/aft directions. In addition, the four areas on
top of the beams on which the isolation mounts will rest need to be co-planar within 1/8th
inch (3 mm) to minimize potential distortion of Seakeeper support frame when installed.
(Similar to Figure 9).
Seakeeper provides an installation fixture assembly, P/N 90089 that 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. The
fixture locates the hole patterns at the proper
spacing, both in the fore-aft direction and the port-
starboard direction. See Figures 5 & 6 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 the Seakeeper envelope dimensions.
Refer to Drawing No. 90271 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.
Figure 5 –Exploded View of Installation Fixture

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Section 1: MECHANICAL INSTALLATION
FIGURE 6 –NOTICE FOR CHECKING SQUARE OF ASSEMBLY

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Section 1: MECHANICAL INSTALLATION
1.5.2 Transfer of Holes to Foundation
1) Lower assembled fixture onto hull
structure.
2) The four areas where the isolation
mounts will rest should be coplanar to
within 1/8” (3 mm). See Figure 9. 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 ø.257 (6.5 mm).
4) Remove fixture and drill holes in foundation
at marked locations to mate with holes in
Seakeeper isolation mounts. A ø.689”
(17.5 mm) hole is recommended for
through-bolt installations.
NOTE: Certain foundation designs that
employ threaded blind holes in thick
plates may require the installer to obtain
alternate fasteners. Reference blind-hole
kit drawing 90614.

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Section 1: MECHANICAL INSTALLATION
1.5.3 Installation of Seakeeper
1) Locate and position 4 isolation gaskets onto
foundation beams. NOTE: A VERY SMALL
AMOUNT OF SEALANT MAY BE APPLIED
TO THE GASKET TO KEEP WATER FROM
WICKING INTO THE JOINT. Isolation
gaskets are only required when mounting to a
structure other than aluminum or GRP.
2) Lower Seakeeper into position onto
foundation beams and align over drilled
holes.
3) Install Seakeeper supplied M16 fasteners as
shown in figure to right–apply a moderate coat
of nickel based anti-seize compound to the
threads of each bolt prior to installation.
4) Torque all fasteners to 100 ft-lbs (136 N-m).
5) Apply a small bead of sealant (silicone or caulk) around the perimeter of each isolation mount
where it rests on the beam. This will prevent water from wicking between the parts and setting
up corrosion.
6) Proceed to electrical and cooling portion of the installation.

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Section 1: MECHANICAL INSTALLATION
1.6 Saddle Installation
Seakeeper recommends a slow curing, non-sagging structural adhesive for bonding the saddles
to the GRP hull structure. Such an adhesive is Plexus MA590 which is a two-part methacrylate
adhesive. Details of the bonding procedure in this manual will involve the Plexus MA590 product,
but that should not exclude other suitable adhesives the installer chooses to use. See Sheet 6 of
Seakeeper drawing no. 90272 for loads information and recommended adhesive
properties.
1.6.1 Initial Check and Preparation of Hull Structure
Refer to Seakeeper Drawing No. 90272, Seakeeper 26/20HD Saddle 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. 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 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 287 in2(1852
cm2) for a total bonded surface area for all four saddles of 1148 in2(7406 cm2).
The hull structure supporting the Seakeeper should be installed so the Seakeeper is parallel to
the water plane in the port/starboard and forward/aft directions. In addition, the four areas on
top of the beams that the saddles will bond to need to be co-planar within 1/8th inch (3 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 90088 that locates the saddles at the
proper spacing both in the fore-aft direction and the port-starboard direction. See Figures 6, 7 &
8 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 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 1 to 3 mm (.04” to .13”).

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Section 1: MECHANICAL INSTALLATION
Note: Do NOT use the installation fixture to establish Seakeeper envelope dimensions.
Refer to Drawing No. 90272 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.
FIGURE 6 –EXPLODED VIEW OF SADDLE INSTALLATION FIXTURE

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Section 1: MECHANICAL INSTALLATION
FIGURE 7 –NOTICE FOR CHECKING SQUARE OF ASSEMBLY

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Section 1: MECHANICAL INSTALLATION
FIGURE 8 –SADDLE INSTALLATION FIXTURE ON NOTIONAL HULL STRUCTURE

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Section 1: MECHANICAL INSTALLATION
1.6.2 Fiberglass Hull Preparation
1) Position installation fixture (Fig 9) on hull girders noting recommended clearances for
maintenance from Figure 2. Check that the screws fastening the saddles to the installation
fixture are tight (Fig 6).
2) Mask hull area (as shown in blue, Fig 10) around foundation saddles for easy clean-up
and to create outline of surface area to receive adhesive as shown in brown, Fig 9. Ensure
that the bond gap is within adhesive manufacturer’s recommended thickness, or 3 mm if
using Plexus MA590.
FIGURE 9 - INSTALLING FIXTURE ON HULL
FIGURE 10 - MASKING PERIMETER OF SADDLES

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Section 1: MECHANICAL INSTALLATION
3) Raise fixture clear of foundation. Check all four mounting areas are co-planar to within
1/8” (3 mm) to each other, as well as parallel to the water line plane, as shown in Fig 11.
4) Thoroughly clean with alcohol or acetone all areas (highlighted in brown, Fig 9) of girders
to be bonded to remove any contaminates. Use new paper towels for cleaning, not shop
rags.
5) Remove all paint and 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. (Note gap will be larger
due to absence of gel-coat.) Seakeeper recommends a maximum gap of 3 mm if using
Plexus MA590.
FIGURE 11 –COPLANAR PROPERTIES OF FOUNDATION

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Section 1: MECHANICAL INSTALLATION
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 10 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 non-composite hull, contact Seakeeper for hull preparation
instructions.
FIGURE 12 –FOAM STRIP INSTALLATION

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Section 1: MECHANICAL INSTALLATION
1.6.3 Seakeeper Saddle Preparation
1) Ensure that screws fastening saddles to the installation fixture are tight (Fig 7).
2) Check that each saddle contains 4 plastic screws which will ensure an adhesive gap of
.080” (2 mm) on top surface of hull as shown in Figure 13.
3) Thoroughly clean with alcohol or acetone the inside surfaces of Seakeeper foundation
saddles to remove any contaminates as shown in Figure 13. 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.
Plastic Screws
Clean inside
surfaces of
saddles
FIGURE 13 - SADDLE CLEANING