When de-rigging yesterday I found my 4m RDM mast stuck at the joint. Probably sand washed into the join as I had a long float while putting my boom back on in the water (Long story).
No go with the four people on the beach. Took it home on the top of the trailer.
Today I tried flexing it with the ends supported as I rotated it. It moved maybe 1 mm.
Then I remembered the 'Shake method' I had seen (on the beach I think).
I stood it up with the tip in the grass and violently shook it back and forth holding it about 50-70cm below the join. If you can picture keeping the mast vertical and pushing back and forth with two hands so the top shakes back and forth. As I did this I rotated it a 1/4 turn every few shakes.
I stopped a few time and had my son try help me try to pull ir apart. Still no go.
On the second attempt, I noticed that there was definitly a larger gap with more ferrule showing.
Had to rest a few times as I am on old fart and it was quite a workout shaking it.
Each time i stopped it was obvious that the gap was growing. After a few go's, it was about 10mm.
We tried pulling to no avail.
More shaking and more movement. At about 20mm. the mast pulled apart easily.
I was flabbergasted to say the least. This is by far the most reliable and effective method I have used.
I hope this helps for someone else.
