Thanks for all the comments. It has certainly made for an interesting discussion. I agree with many that in most situations good organisation, especially with locks, and hand signals suffice in most situations. My main concern was that as there will only me us two on the boat and as my husband has no experience at all he may worry when I disappear round a corner and do not reappear for a while because I am helping other boats coming the other way before we can continue. Also when I crewed on the Llangollan when it was busy boats coming the other way could tell us how many more were coming through before we could go but in early March I suspect it will be less busy and we will not have that opportunity. In September when we crossed the aqueduct we simply followed the trip boat through but if that is not running in March we will not be able to do that. So when it comes to the narrow bits, aqueducts and tunnels I anticipated that I may have to go on ahead and then radio my husband to come through. I just wanted to be sure that when we get there we do not find that the radios only work on line of sight or will not work at a long enough distance or through tunnels but I did not want to spend too much as I suspect that on any other canal we will not find them so useful. I did see some people using them when they could have signalled and it seemed very silly to me.