Small triumph

Our 18' clothesline pole finally, after some 20 years, pulled its base out of the ground, leaned that up against the neighbour's fence, and stayed sort-of-up only because of three metal fenceposts propped into the ground and spiked into it.
The last pole came from the beach, but it took two fit men, with considerable effort, to carry, and I destroyed a car-top carrier getting it home.
I discussed the issue with Hubert, who suggested recycled aluminum pipe, which is, of course, potentially much lighter. Apparently fish farms sometimes recycle it.
As it turned out, the only available aluminum pipe was both much shorter and rather lighter than he had suggested: what I found available at our local metal recycler were two 9' sections of 2.5" aluminum pipe and one 8' square piece. Then a piece of good fortune: the round pipe fitted neatly into the square pipe.
It was pretty clear 2.5" aluminum pipe is really not rigid enough in a 20' length to keep a clothesline happy, especially on a windy day, and I had to, somehow, put the pipe together to make 20'.
Getting someone to weld everything together seemed a troublesome option; besides, I'd still have the issue of getting a 20' pipe home.
In any case, the pole would have to be supported from the back with stays.
After much thought, plus some further advice from Hubert, I elected to cut about 30" off the square pipe, stick the two round pipes into that to meet in the middle, fill most of the gaps with dowling, and then fill any remaining voids with low-expansion foam. Just in case there was any chance of shifting, I added one aluminum screw to the top.
Then I did the same for the base, making sure I had 20' of pole plus about 2' to go into the hole I would prepare to receive it.
The pole was finished off with a rounded length of 2X4 in the top, more foam, and a cap to keep the elements from attacking the vulnerable bits.

Digging the hole was pure grunt work. I knew from experience that not far from the bottom of any hole one digs into Rockland is a rock slightly larger than the hole from which one is trying to extract it. This hole was no exception, but in the end I had a very satisfactory, largeish hole, and a significant pile of boulders with which to refill it.

Recycling the old clothesline, I attached 4 stays, two for the top, and two for just above the join.
Then I got Jay to come help erect the pole while I backfilled the hole with a bag of concrete mix and the boulders.
I cut one of the metal fenceposts in half (love my angle grinder!), pounded each half into Rockland, and drilled holes in them to accommodate the stays.
When everything had set next day, it was time to rig the stays and attach the clothesline to the pulley, readily-accomplished once I had our 21' ladder in place.
And that's another job I won't be doing again in my lifetime!