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"Bob About" Instructions
Copyright 2002 by Brett McCormack
"Bob About" has been under development for several years, It grew
from a series of free sailing models that I built. When I heard
that the "Footy" class had been formed I wasted no time in adapting
my free sailing design for radio.
The yacht will sail quite happily without radio if required, simply
add 150 g. to either the ballast bulb or inside in place of the radio.
This design has been developed by an amateur and must be considered
experimental. The designer accepts no responsibility for accident
or loss occurring as a result of building or using this craft.
If you should decide to build this boat, please contact me at
firstname.lastname@example.org. I'll help you all
I can, and in return I need photographs and feedback about the boat's
construction and her performance.
19 Edinburgh Street,
Dunedin, New Zealand
- Hull, 2 mm balsa or plywood (1/16"), the deck is best made from plywood if you can.
- Rudder shaft 1/8 inch brass rod
- Rudder tube 1/8 ID brass tube
- Mast tube 6mm ID, brass or alloy
- Keel, 2.5mm (3/32") timber
- Rudder 2.5mm timber or wrap 2 sides of thin ply or similar material around shaft
- Lead weight 8 oz fishing sinker or purpose built bulb
- Mast/booms 6mm (1/4") dowel
- Sails rip stop nylon
- Sail reinforcement sail repair tape
- Deck patches from sticky back Dacron or "contact" type material
- 2 large split pins
- 2 small split pins
- 1.6mm s/s wire for forestay
- 1.6mm s/s wire for gooseneck/kicker
- 1.6mm s/s wire for spar joiner / rig holding pin/sheet fairlead
- 3 bowsies, kicker/jibsheet/jib halyard
- Small plastic tube for sheet line
- Light cord, thin kite string from cheap store bought kites works well
- Standard 2 channel radio gear.
Hull Building Instructions
- Cut out bottom, 2 side panels, bow bulkhead and transom.
- Chamfer inside edges of bottom and bottom edge of side panels as shown on general layout plan.
- Join bottom and sides together with tape, making sure that all joints meet nicely.
- Put a piece of scrap timber between the hull sides to hold the hull to the correct beam.
- Fit and tape the bow bulkhead and transom into position.
- When satisfied with all the joints on the hull and that it has no twists or warps, apply glue to around the inside of all the joints.
- Cut out the radio tray, make cut-outs to fit servos. (Note class rules state that only standard size servos can be used.)
- Fit the keel fin to the radio tray; use plenty of glue on this joint.
- Slide the keel through the slot in the bottom panel once satisfied with the radio tray fit and keel alignment, glue in place, again use a generous amount of glue.
- The fins leading and trailing edges should be rounded off.
- Glue the rudder tube into position taking care to ensure alignment. Use a generous fillet of glue to hold in place. Please note the detail on the plan showing the rudder tube extending a little through the hull bottom.
- Glue in place gunwale strips to take the deck as shown.
- Cut out deck and reinforce under mast area with some scrap material.
- Fit the deck and glue in place.
- Install mast tube, again check alignment carefully.
- Use a large fillet of glue around mast tube base.
- Check the weight of the bulb, 200g (8 ounces), adjust if necessary.
- The lead ballast can now be fitted to the fin as shown
- Cut out the rudder and glue in place the brass rudder stock.
- Smooth off all edges on the rudder.
- All the joints on the hull can now be sanded and smoothed off.
- All balsa/plywood parts can be sealed with dope or epoxy resin.
- Install the s/s wire loop and tube as shown on the deck to take the sheet rope.
- Finish paint or varnish to your satisfaction.
- Cut mast to length.... 550mm (21.6").
- Drill 1/16 th hole 4mm above deck level, insert small piece off s/s wire and glue on 120mm and 70mm lengths of dowel to accept jib boom and main sheet respectively.
- Drill and insert split pins in mast to make gooseneck fitting.
- Bend a piece of 1.6mm s/s wire to form the pivoting part for the gooseneck as shown on the plan.
- Connect to the main boom as shown.
- Assemble string and bowsie to form kicking strap.
- Sails can be cut from ripstop nylon; take the sizes from the plan.
- Mainsail can be either pocket luff or tied to mast with loops.
- Notice the jib luff is enclosed in a length of s/s wire, this is important as
it keeps the jib luff from sagging.
- Attach the sheets to the boom and set up sail arm, sail arm length is 65mm (2.5").
500g is a good all up weight for the "BobAbout" design.
So weigh the boat when finnished and subtract it from 500g.
be the weight of the bulb for the boat to float on her lines.
If built carefully you should be able to use about 200g