Sickness has prevent two days of work on the boat but I have used the time to do a lot more product research on lighting, heating and power control.
I have now got to the bottom of DMX. It turns out to be relatively simple. ish. You can use various pieces of software to control a DMX control via ethernet. This then sends out the control signals via a DMX bus to one or more (in a chain) DMX decoders which in turn power and control one or more LED lights. Simples. Each decoder will power a number of LEDs and will allow you to control brightness and colour, including white for normal lighting.
There are also other wall controllers (like light switches) that will drive the LEDs and allow you to control the room lighting from a panel on the wall. But it seems you cannot do both. However further discussions with a supplier showed that in fact the decoders (some of them) have what he termed granny switches which would allow you to wire in a wall switch. But then you have to do certain things back on your ipad to return control back to the software. So not ideal. Its a little surprising that there is not a product that would take control from both the DMX bus or the wall system.
But there may be another option. I am investigating the potential to switch the output of the DMX controllers rather than the input. That (I hope) will mean that the DMX controller would continue to operate and the lights would only come on when the wall switch is on. Some limitations to this are that you could switch off the lights from the software and then the light switch would not work. But actually that would be fine. Just use the software for light adjustment and switch for the main power on/off.
I also found some great touch pad light switches. But these do not work either! Turns out that they run KNX. What the hell is KNX I hear you say. Yep. My reaction too. Turns out that its another home control protocol. Essentially all KNX equipment (which appears to be just about everything from standard sockets to light switches) is controlled from a KNX server. Its pretty amazing stuff. So light switches do not switch on lights but send signals back to the server. The server then uses power actuators to do things like switch on lights. What you can do is pretty clever. You can implement it so that one switch turns on one light. But you can also make it do a whole range of other stuff. You could have a switch in the bedroom that when you activate it, it switches on the heating in the bathroom, switches the kettle on, turns on the lights in the room and the kitchen etc etc. Fun stuff. So if I could use this to control the DMX lighting then I can get the lights and power systems to do some pretty good stuff. You can also wire in motion detectors. So it can follow you through the ship turning on the lights (and off again) as you go. It can switch off lights after a short period. I could have it in 'home alone mode' where any light I switch on automatically switches off all other lights thus keeping the power consumption down.
I also looked at some ideas for bathrooms. These guys http://www.geberit.co.uk/web/appl/uk/wcmsuk.nsf/pages/prod-san-1 look the business.
Finally I spent many hours looking at heating options. Baxi seem to have some of the most innovative. In fact they have a boiler/elect generator system. It will do everything your conventional boiler does and also produce up to 1KW of electricity. Its only 4 amps but it will integrate into your house systems easily and an extra 4 amps will be a big help. They are very vague about the costs of production but there are case studies and its not worth writing it off yet.
They also do a biomass boiler. It runs off wood pellets. It has a big hopper that automatically feeds pellets for days before it needs to be refilled. It looks cheaper to run than gas or elec or oil and of course is totally green. Sounds too good to be true. and of course it is. The smallest one weighs 275kg! Empty. And runs off 5.8 amps of electric. Thats a lot of juice given I only have 16 amps to rely upon. Shame. I could probably cope with the power issue but not sure how I would get 275Kg on board.
More research needed.