Inverted mast problem????????

[sink or swim]

I brought Gryphon 3214 last year, she has an M7 SS mast and I am now sorting her out for Easter. I have wound the spreaders as far back as they can go (165mm) and they are 360mm long but the mast is inverting when I pull on the rig tension. The spreader rake should be giving me more than enough pre bend which it is only the wrong way!!!!!!!!!!!:'( Any ideas or advice would be gratefuly received.
Thanks
Steve Peters

[tonyelgar]

A couple of things i can suggest without seeing it:
Is the mast foot adjustable? could it be moved forward?
Assuming the shrouds are ajustable how are they set when you crank on the rig tension?
Is the mast defo straight? It didnt spend the winter in an awkward place did it?
And does putting the main up make a difference? Sometimes if its marginal it does make a difference when rigged with the main and boom in place.
HAve the spreader lengths been changed? If so this could mean your deflection may not be right even if they re angled beyond what they were before!
Hope this is helpful at all, I know it can be a real pain when you cant find the problem. I'm still getting to grips with my rig (damn swinging spreaders!)
best of luck.
tony

[tedcordall]

I had a similar problem and found that the bottom of the tenon was flat. When upright the mast was then sitting on the front edge of this. This seemed to cause the mast to invert under tension. 

I took a file to the tenon and put a curve on it. This seemed to do the trick.

[andyp]

When I first got the FF we sailed her with the mast almost verticle and straght which was fine until we sailed at Ripon last spring in a real blow and the mast inverted pretty badly on the broad reaches
Graham C very kindly had a look at the set up at lunchtime and pointed out that I had the Jib halyard pulled on too tight (pulling the top of the mast forward) and placed a new calibration mark about 6 inches further down the control line. The result is we now pull  forestay on less and the shrouds on tighter which places the pre bend on the mast

[bendy (Guest)]

Jib halyard too tight is the normal culprit.  I’m assuming that the ram/strut is off or that’ll do it.  Also a minor inversion often disappears when you put the main up, if that’s the case I wouldn’t worry about it.
 
I assume the rig is straight when it’s not in the boat?  Otherwise you’re going to have to jump on, that’s a thread in it’s own right.

[sink or swim]

Thanks to everyone for their advice. Kevan has also sent me an email with some advice so when the weather finally settles down I will set it up again with better results hopefully? I am still thinking about Burton week and depends on how the staying upright part of the sailing is going.
Regards
Steve

[Phil Brown]

We had the same problem as Ted compounded by limited swing spreaders that could move forward ie, not prevent the mast from inverting. FIling the mast foot tenon at the front so that it rested firmly on the back edge did the trick

Phil