HI Pete
For SURFACE USE ONLY there is 27 MHZ 40 MHZ. 35MHZ is for aircraft
There a new frequency of 2.4 GHZ. On the old 27,40,35 mhz freq you have crystals that make up the channels. So if you want to sail and you are red channel on 27mhz and some one else was on the red channel on 27mhz you cant use your radio set as you will cause interference problems
The new 2.4 ghz work on a different system. There are about 99 slots in the 2.4ghz range. So your radio hand set is bonded to the reciver and will only respond to signals from that hand set. When you switch on your radio set it looks for a free slot and if there is one your free to go sailing . So unless there 99+ people on the water edge you will never be waiting. Note 2.4ghz can be use in all rc models planes boats etc expect submarines that go under water as 2.4ghz will not travel through water.
Be careful when choosing your radio set as most 2.4ghz set 6ch have channels 1 to 4 full proportional and channel 5 and 6 are on on ie full servo travel . Some set differ.
This is what you will need to check if you intend to get the crane on your happy hunter working.
On my ferry I am having many working items . I have 2 routes
1. get a fully loaded robbe F14 mega buck not helped with the weak pound.
2. have two radio systems . system 1 40mhz or 2.4ghz controls the boat system 2 a switcher system controls the function ie crane etc. see link
http://www.modelboatmayhem.co.uk/forum/index.php?topic=18065.msg176182#msg176182John