Mast wobble.

[pugwash60]

Sailing yesterday (Wauqiez Gladiateur) I noticed the rigging was a little slack particularly the baby stay. - Downwind in windy and gusty conditions the mast was pumping a bit and felt ‘wobbly’. I’ve not seen this before. I tightened up the back stay a little, halfway to my normal upwind and windy setting but things were still not good. I have a hydraulic tensioner and batten with markings on it to guide me. I was about to tighten up the baby stay when I suddenly wondered about a stalock fitting I’d fitted over the winter on the back stay. Looking at it, it’s possible that some wire may have pulled out of it - slightly fearful for the mast I quickly handed the sails and set the halliard as a back up stay. It’s possible that I stuffed up fitting it and got a wire caught in the slot in the cone. Before i disassemble it I guess I need a new cone to refit?
If it’s not the backstay I can’t think of any reason that the rigging should have slacked off so much. I had been sailing a couple of days prior to this in quite windy conditions, is it possible I can have stretched the wires enough to cause a loose baby stay? Is there anything else I should check?
Rigging was all set up at the beginning of the season with a tension meter. I did a regatta early in the season then nothing for a couple of months (off at work). All bottle screws have been wire locked so they have not slackened Off.
Thanks.

 

[mainsail1]

Hull flexing?

 

[kacecar]

When the mast on my boat suddenly became "loose" it turned out the casting at the foot of the mast (the bit attached to the deck) had broken, allowing the mast to drop a bit.

 

[Yngmar]

Is there anything else I should check?

Yes, everything. Fittings letting go, chainplates pulling out of the hull, tie rods (if any) failing or attachments pulling out, broken wire strands (typically at fittings, but can also happen at spreader ends in a continuous rig), spreaders collapsing, mast fittings failing, backstay tensioner problems, cracked turnbuckle bodies - basically give the whole thing a good looking at, all the way from the bottom up to the top of the mast. With furling foresails, forestay problems are much more likely than backstay ones. If you really can find nothing, it may be hull flex, but I've only seen enough hull deformation to slacken the rig on a brand new catamaran (new GRP hulls tend to have some plastic deformation the first time the rig is tensioned, but that hardly applies to a boat from the late 70s).

For your Sta-Lok swageless fitting, you do need a new cone if yours has a strand pinched in it. You can leave the cone alone if it doesn't move during removal and it turns out there was no problem with a strand in the slot. A good idea to have one aboard in any case.

If you really found nothing, tension it back up, but with halyards as backup and see if anything suddenly goes ping and reveals a hidden problem

 

[Fr J Hackett]

Check the packing at the compression post.

 

[Beelzebub]

Henri Wauquiez was passionate about building solid sea-going boats so I would be surprised if it was hull-related; but who knows what a previous owner may have done with the boat?

The previous posters' points are all valid but don't ignore the possiblity of plain old metal fatigue. Twice I have sailed on boats that suddenly developed extreme "mast-wobble", so much that you could push the mast with one finger amd it would deflect several inches. Once was on a Waarschipp 1/4 Tonner and the other on X-99.

 

[johnalison]

The nearest I have had the that rig was a Sadler 29, and in that case it was the baby stay that went first, initially just one strand which we heard but didn't identify. A week later the stay started to stretch itself as more strands gave. I would check the baby stay carefully, and if this is the cause, then all well, but an all-round check is obviously desirable.

 

[lw395]

Check rake and whether the mast is upright side to side, might tell you where the stretch is?
It's what? a single speader masthead rig? Keel stepped?
If it's a shroud, the mast will be out of shape side to side.
Forestay, you might notice excess rake?

Among other things I would look for the mast extrusion splitting at the base allowing it to drop further over the heel plug.
But essentially, everything needs to be checked, even if you find one problem, check everything else.

 

[richardbrennan]

I had a problem with the mast pumping. Turned out it was the upper intermediates being over tight and preventing the required amount of pre-bend. I imagine you would get the same problem if the backstay has slackened. I would check the pre-bend and see if it is still the same as previous.