Hi All
I just thought I would share my experience with main halyard sheeve. My main became more and more difficult to raise. Eventually it was inspected by my boatyard - Hayling Marine - thanks Ron - and found to be defective. After managing temporarily with the topping lift helping out as a second halyard, we had the mast down. The main halyard sheeve was found to be a plastic wheel with an aloy tube axle. Half of the sheeve had worn away and the axle was warped. So the more pressure that was exerted the worse it performed. It seemed surprisingly light construction.
The mast then had to come down and with much drilling and fiddling about with non standard sheeves Ron managed to get it back to new.
The lesson from this is to keep an eye on your mast sheeves before they jam up from old age and wear and tear.
We have been trying to sail this week but my crew fancies warmer weather so we are absconding via the ferry to seek the sun by car!