Mystery Metal Object plus Living off the Grid

If you are interested in learning about living off the grid 
(no roads, electricity, gas, boat access only ...etc)
then take a look at Dave's blog -
he blogs about how, why, daily happenings etc.
Dispatches from Off the Grid
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Try to guess - what object were these pieces of metal from? 

- the next two pictures are also part of the whole -

Answer tomorrow.
It came to me from my Dad.
Rusted out in my garden.
Well used before I got it.