Originally Posted by Rusty Nail

Remember, you can establish the waterline with the water in the hull, so the outer surface is dry and will take a spirit marker. Make sure it is slightly bow high.

Thanks Rusty!. The way the waterline is marked now the boat's nose rides lower that the stern, this is not right, we desire a slight higher nose. So I need to fill the hull with the water weight (75gm in my case), tilt the hull so the nose rides slightly higher. I then mark a waterline where the water inside the bottle settled.

We later will use this reference line to adjust the location of the fin.
I hope I'm in the ballpark on this one.

Gary

STEP SIX: BULB (2)

Lead is poisonous if it comes in contact with open wounds or is ingested.
Wear plastic gloves whilst working and wash hands well after.
Work on newspaper and discard all shavings in the rubbish.

The lead bulb is responsible for keeping your yacht upright, like a pendulum. The weight of the bulb is determined by the desired displacement, length of fin, size of rig and sailing conditions. The more weight that can be taken from the radio gear and placed on the bulb, the more sail area can be carried.
Choose a suitable shaped and weight bulb from a coastal fishing store, something from 200-250 grams will do.
If you are using the recommended 275mm fin blade and have light radio gear a 200gm bulb is ok. You may choose to have several fin and bulb combinations or several demountable bulbs for a fin, for different conditions.
The most common available size is 8 ounces but they can vary in weight (mine was 7!). A slight imperfection, such as a line anchor, can be beaten streamlined with a hammer, and filled with epoxy putty.

Drill a 1.5mm hole a centimetre deep on the centreline at the point and angle on the bulb that matches the thickest part of the foil. We are looking for a slightly nose high attitude to the bulb in order for it to be streamlined when the hull is running at speed with the bow dropped.
Bend a bicycle spoke at right angles 4 cm from the threaded end. Thread the drilled hole with the spoke.  Cut the spoke off and file or sand rough for gluing. Leave a 5mm bent stub for a slotted fin.

Cut the bottom of the fin to fit the bulb and sand edges for the glue fillet.
For a wooden or plastic fin, you may saw a slot or chase for the bent spoke end in the bottom of the fin at the correct angle to align the bulb. This is easier than drilling an accurate hole in thin, hard material if you don't have a drill press.
Tape a piece of waxed cooking paper over one side of the slot. Mix a small marble sized quantity of epoxy putty and pack the slot around the bulb retaining wire. Make sure the bulb is aligned with the centre line. The pin will bend if necessary.
On fibreglass or carbon fins, drill a hole for the stub and wiggle a pocket in the foam interior. Fill with epoxy glue.
Fare with a putty fillet to minimize drag and stop the bulb twisting on the fin. A wet finger smooths the putty.

For a demountable bulb, drill a 2mm hole all the way through the bulb. Countersink the hole to take a spoke nipple in the bottom. Tighten the nipple on the spoke using the screwdriver slot in the end. File a slot in the top of the bulb to take the fin end.

Sand the bulb, fillet and patches to a smooth finish and give it several coats of proper paint to seal it.

The maximum height of a Footy hull is 300mm. Make sure the distance from the bottom of the bulb to the top of the sail servo arm is 300mm by trimming the top, narrow end of the fin if necessary.

STEP SEVEN: RADIO INSTALLATION (2)
The servos are glued on top of the pot in the lid with their mounting flanges underneath.
Take the top of your pot and cut two holes to take your servos using card patterns previously sized to suit.
The rudder servo is mounted in the lid with its drive shaft centred on the centre-line.  See next step for positioning.
The sail servo is forward of this and to the side, though it helps for symmetrical sail setting to have the fully-in line position (sheet) near to the centre as possible.

If the top of the pot is flexible (good for sealing) it may need reinforcing to take the twisting loads of the sail servo. Glue wood strips to the lid around the servo to stiffen it or better, make a thin ply sub plate between the servos and the lid. Make the servos a push fit into the lid and glue in top and bottom with contact cement fillets.

Place a tight felt washer soaked in petroleum jelly, light grease or oil, over the horns of the servos and a dab on the shaft before fitting to help water proof the servos from splashes in severe conditions. In normal sailing the large free board keeps the pot lid dry.

Take the aerial wire of your receiver and secure it with sticky tape in a wide spiral round the inside of the pot.
Full range check after installation. Then quick check with the transmitter aerial down before each sailing session.
Make sure the radio is set up to give right rudder with right stick! If your transmitter does not have servo reversing, you may need to open it up and swap the outer wires on the rudder potentiometer, and the sail pot too if you want full back stick to be sail sheeted in.
Place the batteries in the bottom of the pot, and position for good balance with scrap foam. AAA batteries are more than sufficient, preferably rechargeable NiMh of around 500mAHr - 1 amp hour. The receiver batteries will outlast a NiCd powered transmitter - watch it’s meter.

Place your receiver inside a balloon to keep if from moisture, especially important in salt air, tie the end. 
Pop a small bag of silica gel in the pot too (often found in food and electronic equipment packaging).

To avoid opening the pot and disturbing the wiring unnecessarily, use a 'switch jack'. This is a switched power socket and plug as used on many chargers. Mount the socket in the lid and wire to your battery and receiver so that you can charge the batteries with the plug in and turn on the system with the plug out. You can monitor the batteries with a 50 ohm resistor loaded volt meter through the socket quickly during use. When sailing a plastic plug can partially go into the socket to water proof.

I Found the video slideshow of this boat

Bottle! Footy Class Simple Model Yacht Construction (5 min 50 sec)

STEP EIGHT: RUDDER CONTROL (1)
Use a small, single arm horn on the rudder servo.
Take a stainless steel paper clip and bend it around the rudder post to form a loop with unequal sides and ninety degree bends on the ends.
Insert the ends into two of the servo horns holes and fix with a short length of heated 3mm ID PVC plastic tube.
The length of the loop protruding past the horn end is at least 15mm internal. The length is determined by the distance between the servo shaft and the rudder shaft, keep more than 40mm. We want the point at which the rudder horn enters the loop at neutral to be equidistant to the rudder and servo pivot points to give a rudder deflection of maximum 30 degrees each side. Too short a loop or big a deflection will lead to binding. Keep the loop as narrow as possible but it must not jam in use! Move the rudder gently by hand to its extremes to check for jamming before use. Make sure the loop is centred on the hull centreline and travels equally each side by revolving the pot lid.

This rudder system is a variant of a Whipstaff and is an ancient rudder linkage on full size ships, reintroduced by Angus Richardson (best wishes). It gives the advantages of small rudder movement with large initial transmitter stick inputs, increasing quickly with large stick movements (exponential). It is also very easy to manufacture and maintain, and allows the radio gear to be removed quickly without uncoupling linkages!

The length of the rudder post arm determines the amount of rudder travel - long arm, less travel.
By bending the up-turned portion back and forth you can fine adjust the throw.

Cut the top of the rudder support tube so the rudder shaft will emerge slightly lower than the servo arm loop, with the centre of the up-turned rudder arm in the loop.
Feed the pre-bent ss spoke rudder shaft through and glue into the appropriate flute in the rudder. You can use a packer tube if the flute is somewhat wide on the shaft - a cotton bud tube.
Make sure the rudder and its arm aligns with the centre line of the hull, and swivels without friction. (Do not move the servo arm aggressively, you may damage gears).
Bend a centimetre of the rudder shaft 90 degrees up and into the bottom of the rudder before cutting off the end.

Glue around the edge of the rudder to seal the flutes if you wish.

A short clip of the rudder (and sail system) operating is contained in the above Vimeo video.

STEP NINE: SAIL RIG (1)
Let's assemble a simple beginner's sailing rig based on an idea by NZer Brett McCormack that bends to de-power on gusts, is balanced with 25% of the sail area forward of the mast, and has few sail adjustments to work well.

A standard rig for medium to light conditions can be fabricated from a SWG14 gauge, 2mm thick plain bicycle wheel spoke.
A better rig uses 13 gauge high carbon spring steel, commonly called music or piano wire, available from hobby stores. A storm rig, or a  large light rig in medium winds, could use up to 12 gauge.  Like many design decisions on yachts, each needs to be considered in relation to every other element of the boat and is subject to trial and experiment. The ultimate goal is to achieve a rig that will twist on high gusts to prevent the yacht being overpowered, and yet be stiff enough to provide good power.

Take a 250mm minimum length and bend it with your pliers or in a vice to a 'Z' shape. Make sure it clears the top of the servo horn by a half centimetre and has a centre length of 100mm and an angle of 65 degrees.
Round the bottom with a file.
Cut off two 3mm or 1/8in ID plastic PVC tubing pieces about 30mm long and thread them on the centre portion of the Z wire. Place them in boiling water and then force the sharp end of a 300mm x 3mm  bamboo skewer though them so that the skewer is fixed on top of the wire.  Slide two 3mm ID plastic tubing lengths on the skewer on the other side of the wire mast.  Take a stainless steel paper clip and pass it through another plastic piece. Bend it back on itself one end and at the other form a triangular loop at right angles. Thread this clew clip on the end of the skewer.

Make a head stay out of 15 or 16 gauge wire bent at a 110 degree angle with a long flanged end of about 70mm. Tie a couple of 300mm lengths of coloured thin plastic strips to the flange for a wind indicator.

STEP TEN: Let's make a sail in 5 minutes! (1)

A big killer in entry level yachts is the vexed question of sails. The toy boats have woefully inadequate cotton or plastic sails, and the good model yachts have a deal of money spent on sails to get acceptable performance.
What we need is something quick and cheap that can be adjusted easily and performs well. And a suite of sails will cost nothing and be made in minutes!
The McCormack rig with these sails represents a major advantage to the beginner and are a prime reason for the Footy Class being such a good place to start.

A sail for medium conditions (4-10 knots) should have a foot of about 300mm a height of 475mm and a luff (leading edge) of 500mm.
Mark out a suitable shape on light card and place it on a smoothed out light weight HDPE shopping bag, so that the folded edge of the bag is aligned with the 500mm luff of the sail.
Place a metal straight edge on the foot and run a hot small 20-40 Watt soldering iron's sharp tip slowly down the ruler.  This will cut and seal the two plastic edges. Repeat with the leach and fat head edges.
For a curved leach (trailing edge) run the iron down the pattern edge.
Now you have a double sided sail with a built in luff pocket!
Cut a small triangle off the corner at the bottom of the luff (tack) for the mast entry and another at the top leach corner for the mast head entry.

Take a 500 mm length of 4mm OD (2mm+ ID) carbon or glass fibre tubing for your mast. Feed it through the tack bottom hole and place the end of the head stay into the top of the tube. Place the end of the mast Z into the bottom of the tube.
If you cannot get a tube, you might try a 3.5 or 4mm fibreglass rod or even a 6mm hard wood dowel. These will be more flexible and heavier and the rods will have to be attached to the wire top and bottom masts with larger 5 or 6mm ID PVC tubing sleeves. This will make it more difficult to dismantle the rig. Cheap kites have fibreglass tubes or rods and fishing poles have tips made of thin carbon or fibre glass tubes.

A mast of 400mm can be used for high wind rigs (9-15 knots), and you could go to 600mm, 1000sq cm for a light airs rig (1-5 knots). Each mast can accommodate different sizes of sail foot lengths to give more flexibility, but be aware that the centre of effort of the sail will move back as the foot increases (move the mast forward). It is important that the top of the mast is above the line of the wire mast in the hull. This means re-bending the wire mast stub's angle that goes into the bottom of the mast.

Place a piece of reinforced duct sticky tape over the bottom leach corner of the sail (clew) to reinforce it and pierce the wire triangular loop through this tape.  Adjust the clew by sliding it along the boom to trim the sail for different conditions.  The sail acts like a wing and needs a maximum draft of 5 percent ratio at the bottom - for a 300 mm foot about 15mm sideways between the sail and the boom. The flatter the wind the flatter the sail.
Tension on the leach can be attained by altering the mast post front angle.
Make a S shaped wire tack clip and attach to the reinforced corner of the tack. Only necessary in high winds to help the sail from lifting and dismantling!
The sail can be further reinforced with one or two horizontal battens of 5mm narrow tape or vinyl strips at the leach to lessen sail flapping.
A length along the top sail edge at the mast head will stop wear.
The carbon or glass fibre mast tube should be reinforced at the top and bottom with a 2cm PVC tube sleeve or glue & Kevlar thread windings to prevent crushing and splitting.

Add vinyl sail registration numbers and the class logo.

STEP ELEVEN: SAIL CONTROL (2)
Perhaps the biggest hurdle a new builder faces is working out and implementing a workable sheeting system. Even plans with sheeting shown tend to confuse the beginner and are beyond youngsters.

Following is a very simple arrangement, designed to be easy to understand, all out in the open, using standard servo throws and arms with little friction, tangle potential and easily adjusted for various rigs. It also has the ability to use the new standard, very cheap, slow 9gm servos by using a Stollery Power Lever!

Take a length of 1.6mm  (16/17 gauge) stainless steel spoke and tightly wrap it around a nail through 360 degrees. Measure to the last hole on the other side of the horn and mark the wire. Remove the wire and bend down at right angles to this mark. Cut off the wire, leaving a 3-4mm bend to go through the re-drilled servo hole. Thread a small washer and then a bead on the other end and bend the wire end down 30mm from the servo shaft and cut off. Refit the wire sail servo arm so that with the servo fully back position the arm is under 90 degrees from the rear centre line. Don't forget the felt washer.
Secure with a longer centre screw.

Tie a short Kevlar thread (sheet) to the boom between the plastic PVC sleeves. These need to be a firm sliding fit on the boom - choose a skewer diameter that matches your 3mm or 1/8th inch tubing. Pass the thread through a small metal or nylon ring on the servo arm.  

Drill a 1.5mm hole into the top of the fin, as far to the rear as possible, through the plastic hull and screw a small screw eye into the fin. Use a drawing pin to start the hole in the hull. Do not over tighten or the screw will break! This secures the fin from sliding out and acts as a sheeting anchor.
Secure the sheet to the screw eye with a bowsie (eye opening faces forward).

To avoid any possibility of the sheet catching it is necessary to keep the boom securing point in front of the servo and behind the screw eye with the bowsie at the sheet anchor point.

A simple bowsie to hold slippery Kevlar line can be made from a ss paper clip wire section with a closed loop in each end. Place a bead in the middle to pull on. Put one bowsie loop on the screw eye. Loop the line at least three times, alternating through each end of the bowsie to secure with friction. Loosen the lines on the bowsie and pull to lengthen the sheet.
Adjust the sheet length with the bowsie and the position on the boom by sliding the plastic retainers, and servo arm position to attain the desired sail travel for each mast position.

Start with the fully back, boom in, servo position. The ring slides down the arm towards the servo so that there is maximum torque on winching in. The arm should be at an angle over 90 degrees to the centre line. If the attachment point of the ring in this position is not central, there is unequal angles on the boom on left to right tacks. 
With the servo arm in the fully forward position, the boom should be close to right angles to the hull centre line.

STEP TWELVE: SAILING (1)
Drill a 2mm mast hole immediately in front of the fin through the hull and into the first full flute in the spine. Accuracy is helped with a pilot hole from a drawing pin first. Try the mast post - it should swing freely in its flute for good light airs performance. Measure forward three flutes and drill another two holes (9mm apart). One of these holes should be close to suiting the Centre of Effort of your sail.

The CE is the geometric centre of the sail forces. This is found by a simple drawing calculation on a triangular sail. Draw three lines on the sail pattern - one from each corner to the middle of the opposite side. Where they cross is the centre of the forces acting on the sail.  With a more complicated shape, like a sail with a curved leach (roach) you can find the CE by alternating hanging a weighted line from two corners of the card sail pattern. Where the lines cross is the CE.

Start with the middle mast hole (step) for a standard sail, rear for a small and front for a larger sail.
If you change your sail size or shape, for example make a sail for light or heavy conditions, then you can easily drill more holes to have the mast anywhere you need. Stick a piece of tape over unused mast holes.

When you sail into a breeze you will notice that the yacht does one of three things:
1) Neutral Helm - the yacht sails pretty much where you point it
2) Lee Helm - the yacht tends to turn away from the wind direction
3) Weather Helm - the yacht tends to turn into the wind direction
The last two require some rudder input to maintain a course. This slows the yacht.
You should trim the sail so that the yacht has a slight tendency to turn into the wind by moving your mast position. You can do this by having the CE in front of the Centre of Lateral Resistance. The CLR is the centre of the hull forces and is easily approximated in the tub. Push the hull sideways along its length with a sharp object . The point on the hull where it moves sideways without turning is the CLR.

Now the interesting part starts where you can adjust and experiment with your yacht to get the best performance. 
Then race against other builders.
Pretty soon you will want to build another to test some new ideas or setups.  
Maybe even design your own...

I hope that this simple (but sophisticated) little yacht will teach you most all you need to know in order to successfully design and make your own yachts. And that you can do it!

Some improvements can be made:

• A stiffer, lighter fin. Helicopter blades come in a variety of materials: plastic, wood, fibreglass, carbon fibre, in increasing order of weight, stiffness and cost. A stiffer mast also helps transfer power.
• Visit a helicopter flying field and beg some damaged blades. Larger ‘copters use wider blades and you can use undamaged sections of these for fins and rudders.
• Make a variety of fin lengths and bulb weights for different conditions
• Make a foiled rudder to reduce drag and improve low speed handling
• Try different rigs including Swing and Bermuda rigs
• Experiment with different boat weights
• Try cutting down a bottle to reduce the freeboard.

Footy Rules: footy.rcsailing.net/rules.php

Footy Registration: footy.rcsailing.net/register.php

Footy Forum: rcsailing.net/forum1/forumdisplay.php

Beaufort Wind Scale: en.wikipedia.org/wiki/Beaufort_Wind_Scale

Sailing: en.wikipedia.org/wiki/Sailing

Superb job Rusty, one of best "how to's" I have seen yet...

RADIO APPENDIX:
Most of the questions I get when walk-ups see these yachts concerns the radio gear. It is apparent that the average Joe has not got a clue what makes the yacht sail around the lake, or whether there is much likelihood of getting it back. Today a lady asked me if I "had ever lost it out in the lake"? Well I'm sailing it now, so obviously, no!

Eyes tend to glaze over when ever something technical is mentioned and technical illiteracy is a real barrier to a new person, kid or adult, getting into radio control modeling. A lot have some radio controlled toy at home so think they could use that for a model yacht.

So this afterword is for the new people who need to get hold of a simple radio system for this model yacht, and don't have access to a local yacht club or other adviser.

Firstly you must choose a suitable set up.  You may already have several models that use radio control. If they are 'toys' they will not be suitable. Cheaper radios are integrated into the toy in such a way that the components are not easily extracted and utilized. Many planes and boats have simple controls powering twin motors for propulsion and turning.
We want a 'proper' radio set that uses separate components that can be utilized in a variety of models. These are usually available from model shops, rather than toy shops.

The most basic system will suit our purposes, known as a two channel set. If you have aspirations to take your modeling further, you should buy a more sophisticated system with 4 or 6 channels. This will allow you to fly aircraft and helicopters, but the extra channels do not have much use in yachting.
Traditionally 2 channel systems have been sold to the model car racing market, and if you have access to one of these sophisticated 1/10th scale kit racing cars, it may have suitable radio equipment. Many car sets now use a wheel and trigger style transmitter, rather than a 'stick' controller. These are less suitable for our purposes.
The component that moves the controls is called a servo.  The older systems come with what was then a 'standard' servo that is moderately powerful and very large and heavy by modern standards. We can use these,  particularly for the sail control.  If you have a choice, particularly when buying new, choose your own servos separate from the radio gear.
The modern servos most commonly used are called 9gm servos, because that is nominally what they weigh. The actual installed weight with control horn, screws and wires is higher. The old servos with similar performance weigh 40 grams!, but can be more robust. A 5-9gm servo is a good choice for our rudder. The yacht we are building uses a balanced rig, special high torque servo arm arrangement and simple sheeting system that allows for smaller sail servos. A 9-16gm 1.7-2kg/cm + torque, highly geared (slower) servo is suitable for moderate wind sailing up to 10 knots. In practice it is not necessary to be able to winch in a highly loaded sail. When running it is possible to briefly unload the sail by bearing away, then winch in and when turning back into wind, to winch in before fully rounding. If the sail arm is adjusted so that it is almost parallel to the hull centre line when fully out, then there is lower stress on the servo gears when holding large loads.

It is not recommended that you buy a new 2 channel AM radio control set, although they are still made and sold!. The technology is way superseded and as mentioned, the stock servos that they come with are too heavy, as is the receiver (40gms), and battery holder is typically for heavy AA cells. However because there are a lot of them about (and 3/4 channel sets) and they are old, a used one should be very cheap or free! You can buy cheap 9gm servos that will plug into it from many online hobby vendors. The TowerPro SG90 or Hextronik HXT900 are reliable cheap servos for less than US$5.

If you prefer a new set, or one with more channels, get the modern 2.4GHz sets. These have weeny aerials, small receivers, and need no crystals to set the frequency of the transmission (so many models can operate at the same time). Reliable 4 channel entry level sets from on line vendors are less than US$30 landed (without servos)! Get a mode two (sail winch lever on the left), and get the next one up (6 ch) that is programmable for a few extra dollars. This will aid in setting the sail winch to give a greater throw, for only another $2! Also get a couple of extra 3ch receivers as these sets only operate with the manufacturer's receivers, and they are cheap! These radios are sold under many brand names and there is a full review here:
https://www.rcgroups.com/forums/show...hobbyking+6+ch
http://www.hobbycity.com/hobbycity/s...2_%28Mode_2%29

Assuming you have found a used simple two channel AM stick radio system, lets check it over and get familiar with it (see it operating before you buy a second hand set!).
Put batteries in the transmitter (8 x AA cells) and receiver (4 x AA cells). Clean the battery contacts and pins and plug the power and servos into the receiver. Make sure the leads plug in the right way round if not polarized. Switch on and move the transmitter sticks. Both servos should move smoothly in proportion to the stick movements. If nothing happens, or one servo does not move, check the polarity of the leads. Check the channel crystals in the transmitter and receiver are the same frequency with 'T' on the transmitter one and 'R' on the receiver, in the correct band - 27 or 29 mHz for AM, marked on the set. Clean the pins and push home. Jiggle them gently in case the crystal socket is loose. Try another crystal set if possible. If movements are jerky or intermittent it is likely on a used set that the potentiometer in the servo or transmitter stick mechanism is dirty. Swap servos in the receiver sockets to eliminate them. Is there interference from another device? If it remains intermittent it is time to open up your transmitter!

RADIO SERVICING: (2)
There are several jobs to do here*:
Firstly, spray the 'pots' with contact cleaner. WD40 or CRC 5.56 will do. Squirt a small amount in any hole near the wire connections on the circular objects attached to the gimbal that have three wires coming from them. These are electo-mechanical devices that suffer from wear and dirt accumulation over time. This leads to intermittent operation of the servos.

Next remove the spring from the left stick that goes up and down. Tape it to the case. This is the sail control and needs to be ratcheted. Ratchets were available for some sets but by now will not be. We can make one out of a small length of thin spring brass or steel wire. Find some where to attach it to the gimbal and rub on the fluted section of the gimbal that moves. You may have to drill a small hole and screw it in place. Adjust so that the stick control will just stay put when you move it.

Third task is to determine if the servos move in the direction you require. Check the transmitter to see if it has servo reverse switches. They may be in the battery compartment, rear, front or bottom of the set. If not we need to swap (unsolder) the two outer wires on the potentiometer. We want the sail servo to turn anticlockwise with the stick fully back, and the rudder servo to turn anticlockwise when you turn left. Alternatively you may find a servo that has 'reverse' travel. Different brands have different default direction for travel. Or, for the sail servo, you can mount it on the opposite side of the pot to reverse travel. Finally, for a few dollars you can buy a electronic device that plugs in the servo line to reverse travel.

Check the crystal socket to make sure it is not loose and is well soldered to the circuit board. Check also the aerial bracket is well soldered. Both these in the transmitter and receiver are areas of wear and tear.

Remove any corrosion on the battery contacts. If NiCd batteries have been stored in it for a long time, check the copper wires from the battery compartment to the circuit board are not blackened. Over time these wires can corrode and lose conductivity and need replacing.

Lastly, whilst we have it open, add a charging socket if it has none, so you can use rechargeable batteries. Buying alkaline AA batteries by the dozen from retail outlets is very expensive. The transmitter will work well with either NiCd or more modern NimH batteries, but the voltage is lower so the battery meter will under read. The NimH have a higher capacity, but you will get several hours from a NiCd, which is more than adequate! You may find enough space in the battery compartment or case to fit a smaller AAA NimH soldered pack. These are more reliable than loose cells.
A unfitted recharge socket option may be on the circuit board, (eg Acoms) but more commonly there will be a three contact power switch. Two of the contacts will be used, one will have no wires. Obtain a suitable power socket and a power diode from an electronics store, typically to take the 2.1 or 2.5mm plug on your charger. Drill a hole in the side or back of the transmitter and fit the socket. Solder two wires to the contacts and wire to the un-used switch contacts. Determine the correct polarity! - the positive of the charger must go to the positive on the battery. You may place a diode in one of the wires if you think some idiot will use the wrong charger  The diode is polarized and will only work in one direction. If you don't have a charger, you can make one with any 12 volt or over DC power pack, a resistor and Ohms law. The resistor value is chosen to give an overnight trickle 1/10th C charge (kinder on the batteries).

OK, put your transmitter back together, and finally do a range test. You should get at least a 100 metre ground range with a long receiver aerial. Some receivers have short half metre aerials, designed for ground use. Learn the range of your system with the transmitter aerial down so you can do a quick range check before sailing.

Before switching on at the water, make sure no one else is operating on the same frequency. On AM six models can operate at the same time in the same band (27 or 29 mHz) on separate crystals. It is common to have a wind indicating ribbon on the transmitter aerial in a colour that indicates your frequency: 26.995 Brown, 27.045 Red, 27.095 Orange, 27.145 Yellow, 27.195 Green, 27.255 Blue.

* Note, these instructions relate to second hand sets - if buying new, get the vendor to undertake alterations so as to not void warranties.

Hi Rusty ~ nice job here well done ~ I have been displaying seven of my Bottle Boats this weekend at the Helicopter Museum following the clubs success at the International SMW event at Telford, where we won best in show - my new big Bottle Boat (800mm long) took pride of place towering over the stand.

Sorry I cant say too much as its embargoed for a magazine article, however its fair to say that's its quick and cost less than £10 to build (less radio gear)

Rgds
AndyT

Andy that is intriguing and you must let us know the illustrated details when possible. An RG65 must therefore be possible!

So great that ingenuity can replace lots of $$ with no decrease in fun.
Unfortunately I think many get stuck in how a yacht has been traditionally made and should look, without going the extra mile in creativity.

Reactions to mine from kids and adults alike is wow when they see it sailing - because it is so small and nips along doing all the maneuvers of a full size yacht. Then as it comes alongside they exclaim, 'Is that a bottle, Mister!?" Just finished my latest as a Christmas present for a seven year old girl, based on 'Young America'. Managed to pick up a dozen used AM transmitters for a few dollars and some new, very small and light modern AM receivers and servos online, so no need to spend much these days for radio gear either.

FREE SAILING:

For the little ones, and the adventurous, there is no shame in ditching the radio gear and going au natural. After all, before radio gear, people had been sailing and racing model yachts for over 100 years.

So if you're radio phobic, cash strapped or like the purist, havoc of it, here's how to make a radio-less Bottle!

Three ways to self-control your yacht:

Weighted Tiller:
Attach a light lead bead weight on the tiller arm so that it is a tight sliding fit on the wire. As the yacht heels the tiller will tilt to the side under gravity and turn the rudder to correct the turn imposed by the heel.
Slide the lead weight on the tiller arm to adjust for differing wind conditions. Suitable for in to wind tacking.

Linked Tiller and Boom:
The tiller and boom are linked with an elastic cord. The cord length is designed to allow the boom to swing out to the angle appropriate for the direction of sailing to the wind. This method can be used for running.
The tiller arm needs to point the opposite way to give the same direction of rudder to the boom swing. Attach an extension to the existing tiller so it points backwards and fix the elastic sheet to the end.

Vane:
This is the most sophisticated self-steering mechanism, invented in 1875 and is used in various sophisticated forms on modern full sized yachts.
A blade like vane is pivoted over the rudder to react to wind pressure over the stern and turn the rudder.

Cut a shape from signboard that avoids the boom and is similar in area to the rudder, with flutes running upright.
Mount a 25x3mm bolt, washer and nut on the pot lid in the same position that the rudder servo shaft would occupy.
Bolt the vane on so it swings freely with the rudder tiller upturned end in one of the vane’s flutes. This will allow the rudder to swing about 10 degrees. This is ideal for fast down wind runs or light wind upwind tacking.
For more rudder movement you can cut out the section between two flutes to give a double section slot. This will allow rudder movements approaching 30 degrees.
Move the pivot point to give access to either deflection mode.
Attach a sheet from the sheet anchor loop to the boom and adjust to about a 10 degree angle for upwind tacks.
The boat will self steer into wind at about 40 degrees to the average wind direction, so choose your launching and destination points carefully!

More historical information on vane steering is here:

A small video clip of Bottle! free sailing with its radio controlled sister is here: