Mast Stability while replacing chainplates

[billdre]

I've decided to replace my chainplates for next season. To be sure about receiving correctly made replacements I'm planning on sending the old ones to the firm that will make the new ones. So the question is ... has anyone left their keel stepped mast up with the upper and lower lateral shrouds removed for any length of time. Forward lower shrouds, plus fore stay and back stay would remain. Also I plan on using the jib and main halyards as lateral support anchored to stanchion bases. The stanchions are mounted on solid layup, no core, with back plates. Has anyone done this? For how long? Was it OK? Thanks.

[2hullvenus]

I'd do it.

You're not putting a sailing load on it. Just leaving it sitting. The halyards can certainly hold it in position, though it may rattle around a little.

[chris95040]

In the water or out? A passing wake could maybe put some load on it.

[donradcliffe]

My keel-stepped boat got a new mast because the yard left it overnight with the shrouds off and the wind came up. Your situation is a little different because you will leave lower shrouds on.

[Blue Stocking]

Interesting that you ask. I just replaced 47 ft, 670lbs of deck stepped douglas fir in Bluestocking. Snugged up all the turnbuckles to motor back to the mooring. Was surprised to watch the uppers alternately slacken as she rolled in a 2 ft sea. I would bridle 2 stout uppers from the biggest size halyard, and let the other 1 do headstay and backstay. Put stoppers of some sort to stop the mast oscilating fore and aft.

[roverhi]

Have done it often changing the rigging and chain plates. Use the halyards to replace the shrouds. Single spreader and probably double spreader masts will stand just fine with only double lower shrouds keeping it erect. With single lowers might want something to hold the mast in place fore and aft.

[billdre]

In reply to Chris95040. Good point. The boat is on the hard. Nothing to affect the mast but wind.

[chris95040]

Originally Posted by Blue Stocking

Interesting that you ask. I just replaced 47 ft, 670lbs of deck stepped douglas fir in Bluestocking. Snugged up all the turnbuckles to motor back to the mooring. Was surprised to watch the uppers alternately slacken as she rolled in a 2 ft sea. I would bridle 2 stout uppers from the biggest size halyard, and let the other 1 do headstay and backstay. Put stoppers of some sort to stop the mast oscilating fore and aft.

What happened?? And what'd you replace it with?

[Blue Stocking]

Originally Posted by chris95040

What happened?? And what'd you replace it with?

Same 50 year old stick. Had it out for overhaul and new standing and running rigging.

[Tingum]

You should be fine, it would take a tropical storm or more to cause worry and even then on the hard you could fill two drums with water and tie to them.

[UNCIVILIZED]

I'm not certain as to how long you plan to leave the mast like this, so some specificity on this would help. Particularly given the time of year, & the fact that the wind associated with the storms is only going to get more intense, more frequently, for the next several months.

That, & I'd say that leaving it like that until Spring, even well stayed (with lines) might not be wise. As if, er, when we get an ice storm, & then some winds, it might create some "issues".

That said, if you do choose to go this route, I'd suggest the highest quality lines possible. Vectran or Spectra, to use for halyards (and bridle legs). And to use each halyard to run a bridle with 2+ legs led to either; some super stout, deck attachment points, or to some lines or webbing strops run underneath of the hull (and back up the opposite sides).

NOTE: There's a couple of perks to running some webbing strops, or Spectra lines, underneath of the hull, ot act as anchors for the ad hoc shrouds.
- You wont have to worry about any deck fittings leaking come Spring.
- And buy transferring the loads to the hull, directly, like this, you wont be stressing your hull to deck joint. As you would, if you anchor things to deck fittings.
Which, if the loads do happen to loosen said joint, it could be a gigantic PITA to rebed later on.
Just a thought.

Might I suggest connecting the bridle legs to your attachment points with Spectra lashings, akin to those use in lieu of turnbuckles on high end racers. As they'll let you get as much tension on things as possible. That, & or perhaps even use the turnbuckles from the shrouds which aren't going to be connected.

Out of curiosity, what are you using for the new chainplates? Duplex Stainless, Titanium, or...

PS: If you're considering leaving the mast up, semi-stayed for a while, might I inquire as to the reason behind not just simply unstepping it?
It never hurts to be able to eyeball the whole rig from close up, when it's sitting on a set of saw horses.

[canyonbat]

Will your idea work? Probably yes. The question really is, are you prepared to deal with the consequences to your boat, or possibly your neighbor's boat, if it doesn't work? Will your insurance cover something like this? If the worst case scenario is something you are ok with then go for it. I would use the two strap and webbing idea posted above.

[billdre]

Thanks Uncivilized for the stropping around the hull idea. It would reduce the need for halyard support since I would simply attach to the original shrouds and web stropping can be had with ratchet tightening mechanisms.
I only want to leave the mast without shrouds as long as it takes for the new chainplates to be made. I was thinking of doing this early Spring after the winter's blow and snow are over. This assumes a reasonable turnaround time during which I would redo the bedding where the chainplates go through the cored deck, ala Don Casey's method of a solid epoxy plug.
I have assumed 316 Stainless was a the best stainless choice. I know the titanium thing but figure that is way too expensive. Expense is the reason for not taking down the mast in the first place. This past year I replaced my roller furler and the installer examined my sheaves and replaced the forestay. So I know the mechanics are good. Basically I do some preventive maintenance or upgrades each year and there don't appear to be any issues with mast components.

[meirriba]

If you leave the shrouds on the boat, you perhaps can use them directly instead of halyards.
Attach shackles to lower ends.
Attach straps with tensioners to the shackles and tension straps around the hull.
Put some soft protection between the hull and straps to protect gellcoat/paint.

[UNCIVILIZED]

First, regarding the headstay. While typically that stay will wear out quicker than the other shrouds, due to the extra weight of the furler & sail, flexing said stay much harder with each wave cycle than the others. But, the thing is, that it's generally wise to replace most of the shrouds about the same time, as they've all seen the same mileage & use/abuse.
It's a general rule of thumb anyway. So the others would bear CLOSE inspection. Perhaps even via one of Brion Toss's pocket magnifiers. They're a handy tool.

On chainplate material, look into the options which I mentioned, as they're free of a lot of regular stainlesses weaknesses. And there are various discussions on the topic over on SA Forums (Sailing Anarchy).
While I can't say that I've done any research into it myself, I ran across a thread over there recently, where a few of the guys said that the costs were pretty reasonable (for chainplate fabrication with the materials which I mentioned).
That, or you could go old school, & use more traditional materials. Which, also happen to be free of the weaknesses inherent in standard stainless. And since you've got the time, it's worth the study. Also, there are some discussions on here about duplex stainless as well.


PS: I'm not familiar with Don Casey's method. Do you have a link or three, or a bit more description so that I can do some googlefu on it?
Also, if you want to go wild, you can re-core the deck in the area where the chainplates are, with a piece of G10 (or the home made version there of).