I don't mind having a cup-a-tea when I am out paddling and I know a few fellas like Dodge and Hairymick do the same. I started experimenting with lightweight home-made metho stoves as a way to ensure I can make the perfect hot cuppa when out in the estuaries or creeks.
Here is the url that started me going:
I experimented with a simple one and haven't had time to do more, but I share what I have done.
I got a small tin of tuna. Cut a small hole in the bottom. The top is ring-pull, but you don't take the lid off. Get the tuna out and eat it with mayo on grain bread. Some catfood tins are the same size, but if you use them, don't eat the contents.
Mark a circle, cut to the circle, fold over the edge to make a folded edge (hopefully not as sharp as a straight cut edge). Put marker for where you will drill.
Make a lid that goes on the centre hole but does not block the drilled air holes.
To operate, put several spoons of metho in the bottom and light it.
After warming up for 30 secs or so, put lid on to cover centre hole. Flame is now forced through the drilled holes.
You can make a windshield which supports the billy. And there you are. A great little cheap but effective billy boiler.