Never shorten your antenna by cutting down its physical length. If possible do not fold it back upon itself. With the older 27/29/36MHz radio systems and their long antennas, you could run it up a stay or along the deck (under if possible). Ideally you would not run it along a metal stay or near metal fittings or servo and power cables.

In AM and FM (pre-2.4GHz) radio systems, if the receiver is not getting clean data from a transmitter then the servos will respond randomly. Only a PCM system (these have a fail-safe for when signal is lost from the transmitter) will hold the last known position.
For this reason, ALWAYS turn your transmitter on first, then receiver. And when turning off, always turn off the receiver first then the transmitter.

All modern radio systems are designed to operate on either 4.8 volts (NiCd/NiMH 4 cells) or 6 volts (Alkaline 4 cells OR NiCd/NiMH 5 cells). It is extremely rare to find a servo or receiver which cannot run between 4.8 and 6V (possibly with very old equipment). 6V is a requirement with most of the sail winches we use, and 6V provides increased speed and torque for your rudder servo.
Unless both the receiver and servos are labelled as HV (high voltage) and suitable for LiPo direct power, do no run your receiver/servos off any battery with higher than 6V.

Yes, but it is not recommended.
LiPo batteries are inherently dangerous. They are not the same as Li-ion batteries in mobile phones or laptops. A short in a LiPo or BEC (Battery Eliminator Circuit) due to a failed BEC or speed controller or in a crash (as in a model airplane crashing) is quite common and they will then generate lots of flames and smoke.
In a model boat/car/plane they have a habit of catching fire if the speed controller is programmed incorrectly.
The author of this article has personally witnessed half a dozen fires caused by LiPo batteries in the Adelaide area, and heard of many more.
LiPo batteries require a special charger, and you must know how to program the charger correctly or it will catch fire. Also you must charge the battery in a fireproof bag outdoors away from anything flammable (like your house or model yacht shed).
If you want to use a LiPo, you must use a BEC to reduce the voltage to 6V. Sometimes you will get lucky and can run your servos and receiver straight off a LiPo, but that is not the norm, and they have a habit of the servo and/or receiver smoking or the LiPo catching fire!

Use either 5 x Sanyo Eneloop (or similar alternate brand) NiMH AA (1900mAh to 2400mAh) rechargeable batteries OR 4 x AA Alkaline batteries in your yacht. Smaller yachts can use 900mAh AAA NiMH cells and still do a long days sailing, but AAs will be better for the higher current drain the sail winch servos can have on a ML45 sized yacht, and you can get several days sailing with these larger batteries.
The Sanyo Eneloop batteries are LSD (low self discharge) which is why they are so popular. The older chemistry NiCd batteries could become flat in 1 week after charging, whereas you can use a LSD NiMH battery pack 1 year from charging.
The NiMH batteries will require a NiMH charger. Do NOT use a NiCd charger as these test for slightly different peak voltages. The NiCd charger can miss the spike in voltage which occurs when a NiMH battery is finished charging and will continue to charge the batteries. An overcharged NiCd battery is usually OK, as it will dissipate the extra charge as heat, but NiMH batteries do not do this well and it will damage the cells.

Yes. As long as the receiver is compatible with the transmitter, you can use a receiver with any number of channels.

Try not to let the antenna touch the push-rods or servo leads. On a model yacht running 2.4GHz it is not as critical as it used to be with 27/29/36MHz systems and the system can operate very well without interference, but best practice is to try not to allow the antenna to make contact with, or run parallel to anything metallic.

No, these are not interchangeable. They will be marked Tx or Rx (Transmitter or Receiver). This only applies to 27/29/36MHz radios. The modern 2.4GHz radios do not have removable crystals.

No, radio systems cannot be modified from AM to FM unless it is a modular radio. In the case of a modular radio the module can be replaced with a module in the other band, or indeed with a 2.4GHz module which may also use it's own built in antenna.

No, these will not work together. There is a similar problem with 2.4GHz systems most people use today. You must have a matching receiver for your transmitter as almost all the different brands of transmitters use different methods to communicate over the same 2.4GHz frequency band. Even within the same brand of transmitter, not all of the same brand of receivers will work as they upgrade/change their transmission methods between models.

Many of the sails you see on the ML45 yachts were made during the Wednesday fortnightly workshops. We have members in the club that will be only too happy to guide you, along with stock of the film and sail tape used including materials to make your own numbers for the sails.

Yes you can!
Many of the ML45 yachts you see were made during the Wednesday fortnightly workshops. We have members in the club that will be only too happy to guide you, along with a stock of much of the materials required.