BENNETT MARINE ST12 Tech Help Resources User Manual
- June 13, 2024
- Bennett Marine
Table of Contents
SPORT TAB
INSTALLATION INSTRUCTIONS
for ST12 and ST16
READ INSTRUCTIONS COMPLETELY BEFORE BEGINNING INSTALLATION
Materials Tools
| 1/2″ Wrench | Vise Grips | Wire Stripper | Wire Cutters |
|---|---|---|---|
| Electric Drill | 3/16″ and 1 /2″ Drill Bits | Teflon Tape | #2 & 3 Phillips Head |
Screw Driver
Four Foot Straightedge| Wire Crimpers| Tape Measure| Marine Epoxy
Marine Grade Sealant| Masking Tape| 1-1/8″ Hole Saw| 1 Qt. Automatic
Transmission Fluid
Step 1 – Position the tabs against the transom and check to see that the upper
mounts of the hydraulic actuators do not center on an inside obstruction. If
they do, reposition tabs slightly outboard. The further outboard the tabs are
mounted the greater the lateral (side to side) control. Position tabs 3″ to 4″
from the chine, and a minimum of 1 O” from the centerline of outboard or
sterndrive unit. (see figure 1). Note: If the inside of the transom-is
inaccessible due to fuel tank, floatation, or other obstruction, call Bennett:
Marine for alternate installation instructions
954-427-1400. (Note: the angled sides
of the ST16 trim tabs face inboard. See figure 2.)
Step 2 – Attach the mounting plates and trim plane with #14 x 1-1/2″ stainless
steel screws 3/8″ above hull bottom (see figure 3). Make 3/16″ pilot holes for
mounting screws. Assemble mounting plates and tab, dip screws in marine
epoxy before running in. Position trim tab between mounting plates before
running screws tight. Snug screws down to secure mounting plates and trim tab
to transom.
Step 3 – Secure the lower hinge of each actuator to the tab with 1/4-20 x 3/4″
Phillips head machine screws. Using a straightedge under the hull bottom set
the “negative angle” of the tab’s trailing edge as shown in figure 2. The
ST16 should have a negative angle of 1-1/4″, the ST12 should be 1″.
Step 4- With tabs set at negative angle, position the upper mounts of the
actuators against the transom. Slide the actuator template behind upper mount,
align and tape to transom.
It is not necessary that the upper mounts lie flat against the transom as the
actuator neck has the ability to flex far more than necessary. The
straightedge may now be removed. Drill holes accurately as indicated on
templates. Drilling a small pilot hole first helps you locate accurate
centers.
Step 5- Install the pipe nipples (dry) snugly into the actuator upper mounts.
Do not use Teflon tape. Use care to avoid cross threading and do not over
tighten (Turn in nipple finger tight, then two full turns with vice grips, NO
MORE).
Apply waterproof sealant on surface around pipe nipples and screw holes.
Insert pipe nipples through transom and secure
actuator upper mounts to transom with #14 x 1-1 /2″ screws. Note: cover the
ends of the pipe nipples with masking tape to prevent dirt or debris from
entering the system. Remove masking tape before making connections inside the
boat.
Step 6- Install hydraulic power unit (HPU) in a convenient location with a dry
environment. Important: the HPU must be mounted in a dry enough location to
avoid submersion and drenching. Allow space over the HPU so that it may be
slid into its mounting bracket. Lay out upper holes on HPU mounting bracket
4-5/8″ apart and start #10 x 1″ screws. Then drill pilot holes for lower
screws and mount bracket. Slide HPU into bracket.
Step 7 – Inside the transom, apply Teflon tape on male threads of pipe nipples
and tighten 90 degree brass elbows to pipe nipples. While tightening elbow,
hold pipe nipple with vise grips to prevent stripping actuator upper mount
threads.
On the port side tab, cut two short runs of hydraulic tubing and attach to
brass tee with “nut with ferrule fitting.” These will be the lines that
connect the two nipples. (To use “nut with ferrule,” insert tubing through
the nut and push until it bottoms in the fitting. While continuing to bottom
the tubing in the fitting, tighten nut “finger tight,” then one full turn with
a 1/2″ wrench … no more). Connect the two short runs of tubing from the brass
tee to the two elbows using the “nut with ferrule” fittings. Connect one end
of the long coil of tubing into the remaining fitting of the brass tee and run
to HPU. Repeat for starboard side tab.
Step 8-With plastic hangers secure hydraulic tubing along hullside or
bulkheads to HPU. When facing HPU the brass fitting on the left of the pump
face connects with the tubing from the port actuators, the fitting on the
right connects with tubing from the starboard actuators. These fittings are
marked “p” 8 “S” for port and starboard. Connect tubing to HPU fittings as
described in Step 7. Use tube bending clips at desired 90 degree bends in
tubing to prevent kinking.
Step 9- Connect HPU ground wire to any convenient ground.
Step 10- Run other end of wire harness to desired location of trim tab control
switch. Secure wire harness with plastic hangers and cut to length. Install
control switch according to “Rocker Switch Installation Instructions.”
Step 11 – Fill HPU reservoir to full line using any type automatic
transmission fluid (ATF). (Hint: An easy way to fill reservoir is to detach
either side hydraulic tubing at tee fitting and insert into a quart container
of ATF. Then press the Rocker Switch “Bow Up” for that tab until reservoir is
full. Reconnect fitting).
Step 12 – Using the Rocker Switch control, press the “Bow Down” position for
15 seconds, then “Bow Up” for 15-20 seconds. Repeat 3 times. This will purge
any air from the system. No bleeding is necessary.
Step 13 — Place both tabs in the “full down” position and check all hydraulic
connections for leaks. Bring the tabs to the full up position and check fluid
level. Add ATF if necessary.
IMPORTANT NOTE FOR BOATS KEPT IN SALT WATER: The black finish of the trim tabs
provides a barrier from electrolytic action. However, if the boat is kept in
saltwater for long periods of time, a zinc anode must be applied to the top
side of each tab. To provide protection, the zinc must make good contact with
the stainless steel. Therefore the coating under the zinc must be removed. Do
not ground the tabs to other underwater appendages. The black finish does not
provide anti-fouling protection and should be painted with anti-fouling paint
if such protection is required.
PLEASE KEEP THIS SHEET AND TRIM TAB OWNERS MANUAL WITH YOUR BOAT’S OPERATING
MANUALS.
For product support, please call
1-866-894-1626 (Option #3), or email
[email protected].
Bennett Marine is a Division of Yamaha Marne Systems Company, Inc. – Learn
more at BennettTrimTabs.com
