PMB PRESTWICH Model Boats
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FSRV Model Boats   Gas Tuned Pipes    Tiger King engines  Kraken mono   Zenoah Marine Engines   Flexishafts

FSRO BOAT BUILDING INSTRUCTIONS  
FSRV BOAT HINTS AND TIPS

View  of PUMA transom showing tube/strut position
Dimension A . 10mm for 7.5cc geared to 11cc.  12 to 14mm for 15 to 25 cc
Dimension B 2 to 4mm (offset to the right)
Dimension B when using Zenoah 5 to 7mm offset to the right.

The dimension B shaft offset is there to compensate for prop walk/prop torque. Without the offset the boat will need left rudder to run straight and will lean to the right.  If your boat does this, then first make sure the propeller is very sharp and then adjust with more offset. 

 

 
 
 

Glowplug to transom with glow engines. 450 to 470mm. With Zenoah 430 to 450 ( transom is the vertical part of the back of the boat.)

Join hull and deck together with fibreglass paste. The outside edges of the lip may not align correctly, so try to align the actual edge of the hull and deck. Cover the lip with fibreglass paste and clamp the top and bottom together with bulldog clips or spring type clothes pegs. For racing it is a good idea to put a layer of glass cloth and resin around the inside of the hull/deck joint and then the lip can be removed completely. For sport use this is not necessary. Fit the engine to the complete rubber mount assembly and position it where shown but do not glue in place yet. Fit the coupling to the motor. Check the drawing above for the position of the tube through the transom. On .90 and Zenoah engines the propshaft should be offset to the right by 3 to 4mm as shown on the drawing. Drill an undersize hole for the proptube in the ‘V’ of the transom . Enlarge the hole with a round file until the tube just fits through it. Seal the tube exit through the transom with silicone tube or silicone sealer. Cut off the lower rudder arm and fit the strut assembly to the transom using the four M4 screws provided and reinforce the inside of the transom if required with a plywood plate or fibreglass mat and resin. Fibreglass the front end of the tube in position at the same time as fitting the engine mount making sure that the tube lines up with the engine coupling. Cut the prop tube to length so that it is about 10 to 12mm from the coupling. Cut the flexi to length, remembering to leave a gap of 5 to 6mm (not less than 5mm) between thrust washer and the strut. Do not cut the flexi too short, because it has to go inside the coupling. The fuel tank can be fitted in front of or behind the engine. Hold the tank in place with rubber bands through hooks fitted to 2 strips of 3/8" wood glued to the hull. The engine can be held temporarily in place with Plasticene whilst the engine mounting feet are tacked in place with thick cyano (superglue). Cut down the feet or pack them up as required. The flexi should slide smoothly into the coupling, to be sure of correct alignment. Fix the mounting feet in position with fibreglass paste. This can be reinforced with fibreglass mat or tape if required. The inside of the deck hatch opening in the deck should be cut back until the hatch fits into it. Fix the hatch down using GA8 hatch fasteners or similar at the rear. At the front, glue to rods or a plate onto the underside of the hatch to locate under the front edge of the hatch opening. Reduce the width of the the lip of the hull with a hacksaw and finish off the edge with coarse production paper or a sanding disc. Fit rubbing strip (GA28) if required to the lip with cyano glue. When the installation is complete, give the inside of the boat a coating of Supaglaze(PM41) to fuel proof it. The radio box can be fibreglassed in place. Only use balanced / sharpened propellers. We recommend Octura props.

For all engines up to and including .67( 11cc) use 3/16 flexicable with 3/16 stubshaft.

For .80/90/100engines use 1/4" flexi stepped down to 3/16" shaft. For Zenoahs and other petrol engines use 1/4" flexi with 1/4" stubshaft.