Construction and Set-Up of a P.I.P. 24” fiberglass
shovelnose hydroplane hull
Ralph von Eppinghoven
Metro Marine Modelers
1: Finished shovelnose hydroplane with tail fin, decals, and scale driver
SECTION 1: BOAT DESCRIPTION
Hull: P.I.P. 24” fiberglass shovelnose
Motor: FD-EM SS1 “Speed 700”
Hardware: Fine Design
Shaft: Octura 0.130” flex
Propeller: Octura X447 or X645
Speed Control: Astroflight 212D (not
Radio System: Hitec Lynx FM (not supplied)
Power: 12 Sanyo RC 2400s in two 6 cell packs
extremely popular category of “fast electric” radio control model boat is
the Limited Sport Hydroplane (LSH) class. To meet the demands of the fast
electric R.C. boater, Fine Design Marine (www.finedesignrc.com)
has started supplying complete, “shovelnose” hydroplane boat kits that
include hull, running hardware, motor, motor mount, flex shaft, coupler,
pushrod, turn fin and all fasteners required to put a competitive, 12-cell,
LSH R.C. boat on the water. The FDM kit is based on the Precision in
Perfection (PIP) “Spirit of Bavaria”, 24 inch, fibreglass hydroplane hull.
article describes the construction and set-up of the FDM kit, along with
optional detailing to make the finished model resemble the real 1965 Miss
Bardahl hydroplane. This article covers a modified version of the PIP hull
that includes a tail fin, scale driver and cockpit. These detailing
modifications are optional, and are only recommended for experienced
modelers. The sections of this article that relate to these optional
modifications are indicated as Optional.
SECTION 2: SURFACE DRIVE
The 7/32” brass stuffing tube is installed as
shown in Photo 2. The stuffing tube slot in the hull bottom is 1-1/2” long
and is located 3-1/4” to 4-3/4” from the transom. The slot should be cut
1/8” wide then carefully filed to snugly fit the stuffing tube. Once the
brass stuffing tube has been bent to the correct shape (see Photo 3 and 4),
“tack” glue the brass tube in place in the slot in the hull bottom using
medium CA glue. Glue the stuffing tube from both the inside and outside of
the hull. Once the CA has dried, apply epoxy glue to the stuffing tube and
hull joint on the inside and outside of the hull. This layer of epoxy glue
is critical to provide waterproofing and strength on this key joint. It is
best to carefully test fit the stuffing tube prior to gluing to ensure that
it is lined up “dead straight” with the motor and strut. The length of the
brass stuffing tube should be such that a gap of approximately 3/16” exists
between the motor coupler and stuffing tube, and that the tube ends
approximately 5/8” in front of the strut.
Photo 2: Stuffing tube on bottom of hull
Motor Mount Installation:
to support the motor at an angle and thereby minimize the bends in the flex
shaft, a small wooden wedge is glued into the hull and the composite, motor
mount is glued to the wedge as shown in Photo 3.
Photo 3: Stuffing tube and motor
mount in side hull
end of the wooden wedge and motor mount (the end nearest the stern of the
boat) should be glued 8-1/4” from the transom (see photo 3). This places the
highest part of the motor within the raised part of the hatch, just in front
of the driver cockpit. Test fit the SS1 motor and mount prior to final
gluing to ensure proper fit and adequate clearance of the motor and coupler
from the bottom of the hull and underside of the hatch, and that the motor
aligns with the stuffing tube.
SECTION 3: HARWARE AND TURN
bracket and strut are installed as shown in Photo 4. The strut is installed
in the bracket so that the upper edge of the strut bullet has 1/8” clearance
below the bottom of the hull.
Photo 4: Running hardware
installed on hull (side view)
in Photo 5, the rudder is mounted offset 1-5/8” to the left of the center
line of the strut bracket.
Photo 5: Running hardware
installed on hull (rear views)
Turn Fin Installation:
fin is screwed to the back of the right sponson and is installed on an angle
(approximately 30 degrees) to help hold the right sponson in the water and
preventing the boat from flipping while cornering at top speed. Photo 6
shows the finished installation of the turn fin.
Photo 6: Installed hydroplane
SECTION 4: INTERIOR
The batteries, ESC, servo and receiver are
placed in the hull as shown in Photo 7. This layout results in
Centre of Gravity (C of G) of approximately 1-¼” behind the back of the
sponson (about the centre of the turn fin). This is the balance point that
results in good speed and handling for this boat. The C of G can be adjusted
easily by moving the battery packs forward or backward in the hull. When
running the boat in choppy water, the batteries should be moved forward 1”
of the original position while calm water running allows the batteries to be
moved back 1”. In this case, the battery packs are offset slightly to the
right of centre to avoid flipping the boat while oval racing.
Photo 7: Interior layout of the
in Photo 7, a cooling coil and brush coolers were installed on the motor.
This is not necessary with the SS1 motor when it is used for typical oval
racing. Also, a 5/32” plywood bulkhead was installed in front of the motor
to stiffen the hull and minimize the flexing of the hull bottom. The
bulkhead should fit fully across the bottom and up the sides of the hull as
shown in Photo 7.
shows the servo installed in the hull. The servo is screwed into two, small,
wooden blocks that are glued onto the bottom of the hull. The servo is
mounted between these blocks. In this case, the rearmost edge of the servo
was mounted 4” forward of the transom. The pushrod and pushrod boot are
installed as shown in Photo 5.
Photo 8: Servo and pushrod
installed in hull
be noted that the servo installation as shown in photo 8 requires the
radio system steering control (on the transmitter) to be set to the
“reverse” setting for the boat to turn in the expected direction.
SECTION 5: RADIO RECEIVER
receiver is mounted in the rear right corner of the hull as shown in Photo
9. Note, the receiver is normally in a waterproof “ballon” but this has been
removed for clarity. The separate red wire shown in the photo is the power
wire from the ESC that is disconnected since a separate radio battery pack
is used instead of the “battery eliminator circuit” from the ESC.
Photo 9: Radio receiver and AA
batteries installed in the hull
to ensure reliable operation of the radio system, it is recommended to power
the radio receiver using the battery pack and on/off switch supplied with
the radio system. In order to access the on/off switch when the hatch is
sealed, the Du-bro Kwik Switch Mount has been installed on the transom.
SECTION 6: HATCH DETAILING
FOR SCALE APPEARANCE (Optional)
This section deals entirely with detailed modelling techniques to add a
driver figure, cockpit, engine exhaust pipes and tail fin to the hatch.
Advanced modelling skills are required for this work since the pieces will
all be built from “scratch”. These details are simply to provide a realistic
and scale boat appearance to the model.
Driver Figure (Optional):
driver figure is based on the Williams Brothers 1/12 Military Scale Pilot
(#17000). Arms and torso can be added by carving these pieces from ½” balsa
wood and gluing them to the Williams Brothers figure. The driver figure’s
hands were simply cut from a child’s toy that had hands that were
approximately the correct size. Assemble the figure by first gluing the arms
in the desired position and then gluing the lower torso between the arms.
Fill any undesired gaps or imperfections using Squadron putty. The steering
wheel is a piece of insulated, 12 gauge, wire that is bent to shape. The
final step is to glue a small piece of plywood, with a blind nut in place,
on the underside of the driver figure. The blind nut should be installed on
top of the piece of plywood with the opening towards the bottom of the
driver torso. This allows a machine screw to be inserted though the
underside of the hatch to fasten the driver securely in place. Photo 10
shows the driver figure assembled and painted.
Photo 10: Scale driver figure
Instrument Panel (Optional):
instrument panel is simply a thin strip of ABS plastic that has ¼ “ holes
spaced equally across its length to simulate instrument bezels, and paper
instrument faces are glued in place behind the panel. The finished and
painted instrument panel is shown in Photo 11.
Photo 11: Finished instrument
panel in cockpit
Engine Exhaust Pipes (Optional):
The dummy exhaust pipes (supplied as an option in
the kit) are attached to the engine area to replicate the real exhausts on
the unlimited class of hydroplane boats. Four equally spaced ¼” holes are
drilled into the engine “rocker covers” molded into the hatch and the
exhausts are glued in place from the underside of the hatch. Photo 11 shows
the dummy exhaust pipes installed in the hatch.
Tail Fin (Optional):
The supplied hatch does not come with the tail fin
that was found on most real shovelnose hydroplanes. In this case, a replica
tail fin was cut out of 5/32” aircraft plywood and glued onto the hatch. In
order to ensure a solid joint between the wooden tail fin and the fiberglass
hatch, tabs on the wooden tail fin are inserted into slots that are cut into
the curved rear section of the hatch. Photo 12 shows the wooden tail fin and
how it is glued to the hatch.
Plywood tail fin glued in place on hatch
SECTION 7: PAINTING AND
shovelnose hydroplane kit hull is made of high quality, gel coated,
fibreglass and does not require painting. If desired, the hull can be
painted to improve its appearance. In this case, the boat hull has been
painted and decaled to be a replica of a real hydroplane – the 1965 Miss
Painting the Black “Batwing” (Optional):
the hull coats of paint are fully dried (this should be at least 72 hours),
the black trim paint on the bow of the boat can be applied which replicates
the black “batwing” of the 1965 Miss Bardahl. Carefully apply strips of
wide, low tack, masking tape across the bow section of the hull. Be sure to
slightly overlap the tape strips so that a large taped surface is formed.
Using an ordinary lead pencil, draw the desired batwing pattern onto the
tape on the bow section. Once the hand drawn pattern is satisfactory,
carefully remove the tape as a single sheet – do not remove the tape strips
individually. Place the tape sheet with the pattern on a clean, dry, cutting
surface such as a sheet of glass. Now carefully cut out the hand drawn
“batwing” pattern, using a fresh exacto knife blade, from the tape sheet
thereby producing the desired batwing mask. Return the batwing mask portion
of the tape sheet back onto its original location on the bow portion of the
hull. Carefully smooth out the tape sheet onto the bow, particularly at the
edges of the mask. Finally, mask the lower edge of the bow to prevent paint
overspray from marring the bottom of the hull. The finished batwing mask is
shown installed on the bow of the boat in Photo 13. Once the mask is
complete, spray paint the exposed area black using desired Black paint.
13: Batwing mask on bow of hull
example, custom-made “Miss Bardahl” decals have been applied to the hull.
These decals are available from either Fine Design Marine or the decal
manufacturer, Axxent Signs in Toronto, Ontario (www.axxentsigns.com).
Photo 1 and 14 shows the locations of the various decals.
14: Decals applied to finished boat
order to protect the decals, stripes and paint, and to provide a glossy
shine to the finished boat, a final layer of “clear coat” paint should be
applied to the entire hull surface.
SECTION 8: SET UP AND
Sealing the Hatch:
most common method of securing the hatch to the deck is to tape the hatch
with electrical tape. Good results have been obtained using the 3M
Colourflex brand of electrical tape (available in green!)
case, the hatch is secured with six, 1” machine screws and blind nuts (Du-bro
socket head bolt and blind nut set - Cat No. #130), instead of taping the
hatch in place. Holes were drilled at the appropriate locations in the hatch
and hull and the blind nuts were glued in place under the hull deck. In
order to ensure a watertight seal, Du-bro Instant Stik Foam Tape was applied
to the edges of the hull opening. This hatch seal was “bathtub tested” with
the boat fully submerged to ensure that it is waterproof.
Balance and Trim:
boat, as configured in this example, will have a C of G of approximately
1-1/4” behind the back of the sponson. This is the balance point that seemed
to result in good speed and handling for this boat. Generally, good results
have been obtained with the strut angle neutral – perfectly level – at a
depth of 1/8” below the bottom of the hull as shown in Photo 4. This boat
has been measured at 30 mph (using a Garmain e-Trex GPS) when set up as
described and using an Octura X447 prop. Using a 12-cell pack of RC2400
batteries, this boat capable of racing for 10 laps on a standard oval
15: The finished FDM Shovelnose Hydroplane – enjoy your fast electric boat!
layout and set up of this shovelnose hydro was based on information provided
to me by Chris Fine at Fine Design, and my fellow Fast Electric boat racers
at Metro Marine Modelers in Toronto, Ontario. I wish to thank all those that
helped me build this great R.C. boat.