Swiebertje – thats what I thought prebend could cause problems at deck level – my boat had been previously raced and had a vicious kicker on it. My friend who is a rigger and maintains many Wayfarer training boats (he was also Flying Fifteen World Champion for a years as crew – probably still is!) said that this was quite usual on Wayfarers and that the sleeve was his standard fix – he’d never had any problems. What do you know that I don’t? I’d be interested to hear your recommendations.
Cracks occur at the front of the mast where it is stretched when it is bend (the rear is compressed). The sleeve is fixed to the mast at the rear by only four rivets hence it does not take the stretching forces at the front of the mast.(The front can still move inside the sleeve). A doubler could work but only if it is fixed to the front of the mast. But if you fix it with rivets in the front, the holes may cause yet more cracks. In general you don’t want holes in the front of the mast where the stretching forces are strongest (at deck level) and this is also the spot where it is point loaded. The only good way to fix a crack is by welding it. And if it is a big crack it may have to be reinforced by doubling it. A doubler is a sleeve that is welded to the mast on all sides.
Welding most probably changes the bend characteristics of the mast. Maybe you are better of with a new one? A new mast does not need to be expensive if you buy a bare mast and transfer the fittings yourself. Also you need to ask why the cracks are there? Has the mast been over stretched? Is it material fatigue? A crack is often a sign of something much worse. If a crack is fixed (welded) chances are a new one will appear next to the fixed one because the mast has worn out, its past its time, its a dead parrot.
The blue collar’s sole purpose is to beef up the mast where it is point loaded by chocks or by the deck. The collar spreads the load over a larger area of the actual mast thus protecting it (a little) without influencing the bend characteristics. It also prevents chafing of the actual mast. As such it may prolongate the life of a mast by preventing damage, it does not fix damage.