ARCTURUS MARINE TRAC Series User manual

ARCTURUSMMAARRIINNEE
AMERICAN BOW THRUSTER
TRAC Series
DC Thruster Installation and
Operation Manual

American Bow Thruster
Standard Installation and Operating Instructions
Version 9.05a
DC TRAC Table of Contents
Section 1 - Before Starting Installation: 1-1
Technical Assistance 1-1
Section 2 - Basic Component Installation: 2-1
Tunnel Installation 2-1
Thruster Mounting 2-4
Propeller Mounting / Safety Wiring 2-5
Header Tank Mounting / Gearbox Oil 2-6
Electrical Component Installation 2-7
Bell Housing/Motor Mounting 2-8
Section 3 - (Section Removed)
Section 4 - Wiring: 4-1
Section 5 - Miscellaneous pre-start-up notes: 5-1
Section 6 - Final Check: 6-1
Section 7 - Thruster Operation: 7-1
Section 8 - System Drawings (Assembly & Wiring) 8-1
Arcturus Marine
American Bow Thruster
517-A Martin Avenue
Rohnert Park, CA 94928
U.S.A
Phone [phone]
FAX [phone]

1-1
Section 1 - Before Starting Installation:
Please read this manual in its entirety before starting installation! It will save you money!
Technical Assistance:
If you have any questions, please call us at [phone] or [phone] or [phone]. We want to
help!

Section 2 - Basic Component Installation
Tunnel Installation:
Warning: Thruster tunnel becomes an integral part of the hull. Installation of thruster tunnel should be
undertaken only by professionals with certified competency in the fabrication and repair of the hull material in
question. Proper mechanical bonding of the tunnel to the hull and support of the tunnel must be confirmed
and certified with your naval architect.
Tunnel Positioning:
Priority 1 - Locate top of tunnel at least 1/2 diameter below the waterline. It is strongly recomended that this
distance be at least 1 diameter whenever possible. Deeper is better.
Priority 2 - Locate the tunnel as far forward as possible while maintaining adequate tunnel length. At a
minimum, the tunnel must be long enough so that no part of the thruster protrudes. Ideally the tunnel length
would be at least 3 diameters.
Marking the Tunnel Cut-out:
1 - Measure and re-measure to exactly pinpoint the center of the tunnel on the inside of the hull on both sides.
Be sure that the location is square in all directions.
2 - Drill a horizontal 3/16" diameter hole through the hull at each center point.
3 - Fabricate a scribing tool from 1/8" steel rod as shown. Bend the end of the rod into a hook shape having a
diameter equal to the tunnels O.D. radius. Pass the scribing tool through the holes in the hull as shown and
scribe the tunnel openings on both sides of the hull.
4 - Cut holes in both sides of hull at scribe mark. Try to hold cutting device paralell to the ground.
2-1
Position tunnel as far forward and deep as
possible without making tunnel too short.
A minimum tunnel length of 3 diameters is
recomended.
Preferred
submergence
is 1 diameter
or more.
waterline

2-2
Tunnel/Hull Joint Radius:
To minimize inlet turbulence, which can reduce thrust, it is best if the tunnel/hull joint radius be not more or
less than 1/10 the tunnel diameter. It is recognized that fabrication of such a radius can be quite time con-
suming and expensive. It should be noted that this reccomendation is made in the pursuit of an ideal situation
and that in practice is not often achieved.
On steel and aluminum tunnels, where such a radius is most difficult, but where performance is critical, a 45
degree chamfer, also 1/10 the tunnel diameter in dimension, can be fabricated at the tunnel/hull joint.
Other Tunnel/Hull Joint Treatments:
The "eyebrow":
This treatment was very common 5-10 years ago. An "eyebrow" would be built up at the leading edge of the
tunnel. The theory was that the eyebrow would deflect water from "tripping" on the trailing edge of the tunnel
and thus reducing turbulence drag. It is our opinion that this theory is not technically supportable. However, it
is acknowledged that an eyebrow may have some benefit in deflecting larger debris from hitting the trailing
edge of the tunnel although damage to a vessel from this type of impact has never been reported. Eyebrows
have also been used sucessfully in the reduction of propeller freewheeling while underway.(See page 2-3)
Optimum radius or chamfer = 1/10 tunnel
diameter.

2-3
The "scallop":
Some builders have taken the approach of scalloping out the hull at the trailing edge of the tunnel in order to
soften or eliminate the tunnel edge. It is reasoned that, left untreated, the trailing edge of the tunnel would
cause turbulence and hull drag. This approach is expensive because of the extensive hull work required.
When builders have done tank tests to determine which type of tunnel treatment is best, the results have
shown drag to be negligible (even unmeasurable) with or without tunnel treatments.
Propeller Free-Wheeling:
For some hull shapes water flow through the tunnel while the vessel is underway can cause the thruster
propeller and motor to spin at high rpm under some sea conditions. For DC motor driven thrusters, this can
be an unacceptable problem mainly due to the resultant high level of noise.
There have been two approaches to addressing the free-wheeling problem. One has been to install a tunnel
eyebrow as described above. The other has been to install tunnel gratings as described below. The effec-
tiveness of either approach is probably due to a lessening of flow into the tunnel when water is encouraged to
flow over the surface of the tunnel opening.
All thruster propellers free-wheel to some extent while underway. Only those that turn fast enough to gener-
ate significant noise would require special measures. We would recommend, particularly on high speed
vessels (speeds exceeding 10 to 12 kts), that gratings be considered as a preventive measure.
Few vessels experience a free-wheeling problem, but those that do tend to have similar characteristics:
1) the tunnels are extremely short
2) the hulls have very fine entry at the bow
Tunnel gratings:
Tunnel gratings are installed to keep people and large debris out of thruster tunnels. We recomend the use of
tunnel gratings for these reasons and also to minimize the probability of free-wheeling problems.
Bars made of 1/4" stainless steel flat stock, 1" to 2" wide, are fixed at 3" to 3.5" intervals across the tunnel
opening. Material size can vary with tunnel diameter. The bars are oriented perpendicular to the normal flow
of water across the tunnel opening (i.e. bars will be approximately vertical, not horizontal).
Methods of fixing bars can include perimeter rings, or screw tabs integrated into the tunnel wall.

Thruster Mounting:
The thruster is secured into the tunnel with six socket head cap screws. Screw diameter and material varies
with thruster size and material. Use only the screws supplied by American Bow Thruster. A gasket is usually
installed between the top of the thruster strut and the inside surface of the tunnel. Because of tunnel diameter
variances, it is acceptable to: (1) use one of the gaskets provided, (2) use two gaskets, or (3) use no gaskets
at all. In the latter case, Sikaflex® sealant should be used between the thruster strut and the tunnel wall.
Checking propeller tip clearance:
Test mount the thruster in the tunnel using a single gasket. Pull the thruster up tight with the screws provided.
Slide both propellers onto their respective shafts and check for acceptable tip clearance. A minimum tip gap
of .050" is recommended. Ideal tip clearance would be 0.10". In exceptional circumstances tip clearance
may be greater depending on tunnel material and tunnel condition. Aluminum tunnels may deform during
installation and present more variablility for tip clearance.
Because the thruster strut is machined with the same radius as the inside of the tunnel, the strut is inclined to
align itself axially in the tunnel. This tends to result in propeller shafts being well centered. However, by
loosening the mounting screws the thruster's axial alignment can be adjusted to improve propeller tip clear-
ance.
Also, the addition or removal of the normal mounting gasket may help to acheive optimal tip clearances.
When it has been established that the propeller tip clearance is acceptable, remove the propellers and
dismount the thruster.
Final Thruster Mounting:
• Carefully clean the mounting surfaces on the thruster strut and the inside of the tunnel.
• Apply RTV silicone to both sides of the gasket (If a gasket is not being used, coat the thruster mounting
surface with an underwater gasket material such as Sikaflex®).
• With the gasket in place, fasten the thruster into the tunnel with the screws provided. Screw threads should
be coated with anti-seizing compound.
• Before tightening mounting screws, slide props in place to be sure that thruster is centered properly.
• Torque mounting screws to the values shown on the appropriate Thruster Assembly drawing.
• Install safety wire through the thruster mounting screws to secure them against vibration (see pg.2-5).
2-4

Propeller Mounting:
1) Clean the propeller shaft and the inside of the propeller hub. Test fit the propeller onto the shaft with the
shaft key installed in the keyway. The propeller should make up cleanly on the shaft. If the propeller does not
fit snugly, then remove the propeller and correct the problem.
2) For final mounting fit key into shaft keyway then install the prop onto the clean and dry shaft. Slide the
propeller onto shaft, making sure the key does not “cock up”.
3) Slide the prop nut washer onto shaft end (when provided).
4) Coat the prop shaft threads with high strength locking compound.
5) Tighten prop nut to the torque listed on the Thruster Assembly Drawing.
Prop nut materials:
Bronze thrusters must use Monel nuts. These nuts are usually marked “NICU”.
Aluminum thrusters must use 316 stainless nuts (usually marked "316")
6) Check that the installed propeller rotates freely and does not bind against the face of the thruster gearbox.
7) Insert and secure the prop nut cotter pin through its hole at the end of the shaft.
8) Install nose cone (except on 8" size) to the face of propeller with the screws provided. Coat screws with
mediumstrength locking compound and tighten to 8 ft-lb.
Nose cone screw materials:
Bronze thrusters must use Monel screws. These screws are usually marked “NICU".
Aluminum thrusters must use 316 stainless screws. These screws are usually marked "316".
Safety Wiring the Thruster Mounting Bolts:
After Installing the thruster in the tunnel (refer to the Thruster Assembly Drawing) the six thruster mounting
bolts must be secured against loosening with safety wire. Mounting bolts supplied by American Bow Thruster
are pre-drilled to accept this wire. Stainless safety wire is included in the thruster mounting kit, and must be
used. Refer to the illustration here for proper wiring technique.
2-5
THRUSTER
GASKET
TUNNEL
WASHERS
MOUNTING BOLTS
Safety wire should pull bolts tight 
to prevent them from loosening.

Route safety wire around bolt heads in a
direction that pulls bolts tight and opposes
loosening rotation

2-6
Header Tank Mounting/Lubrication Requirements:
Warning! on some systems,the header tank fitting and plumbing must be connected before the driveline or
motor are installed, or they cannot be reached.
The header tank maintains positive fluid pressure inside the thruster gearbox to prevent water
intrusion in the unlikely event of a leak. Although rare, the most probable source of a leak in the thruster is
through the shaft seals.
In the event of a leak, case fluid will slowly seep out of the thruster gearbox, rather than water seeping in.
The fluid level in the header tank should be monitored on a regular basis, and must be kept 1/2 full.
1- Using the brackets provided, mount the header tank in any convenient location near the thruster. The
header tank must be mounted at least 30" above the waterline.
2- Connect the header tank hose to the supplied fitting on the thruster with the 3/8" diameter, oil resistant,
low pressure hose. The fittings on the header tank and the thruster are -6 male JIC.
3- Fasten the hose along its route to the hull or bulkhead with nylon straps or clamps at one foot intervals.
NOTE: Be sure that the hose cannot be pinched or become crimped at a later date by stowed gear or
equipment.
4- Remove the breather cap on the header tank and begin filling with the gear oil supplied.
NOTE: Use ONLY Chevron Delo Gear Lubricant SAE 80-90.
Thruster is shipped pre-filled with gear oil.
5- fill the header tank approximately 1/2 full. Store remaining fluid for future use.
MOTOR BELLHOUSING
WATERLINE
HEADER TANK
A/C, DC OR HYDRAULIC MOTOR

Thruster Control Station (TCS) Installation:
Thruster Control Stations should be located at steering stations near main
engine throttle and shift controls. A console cut-out template and gasket is
provided with each unit. Make the console cut-out as shown and drill the
four mounting holes. The control station mounts to the console with four
pre-installed stainless 10-32 studs. Extra long coupling nuts are provided
for tightening from the rear.
The portion of the control station that extends below the console is NOT
weather resistant. In situations where the area below the mounting
surface is open to the environment, a protective cover for the bottom of the
control station must be fabricated.
Central Control Box Installation:
The central control box is typically mounted in a dry location for
convenient wire runs to location of the thruster motor and to the
locations of thruster control stations. Consult the System Electrical
Wiring Diagram to review wire runs. A location should be selected
where ambient temperature will not exceed 120 degrees F. Ac-
cess to the central box should be made convenient for trouble-
shooting.
In most systems, all control wires connect to the Central Control
Box. Consult the System Electrical Wiring Diagram for number and
size of control wires.
2-7