Tabernacle Mooring Question

For issues common to different models of DaySailer.
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Re: Tabernacle Mooring Question

Postby SUNBIRD » Mon Apr 25, 2016 3:59 pm

It may have been at one of the swage fittings, or my memory may be fogged by time, and the failure may have been due to weakening of the wire after a lightning strike. Still, the loose rigging allowing the mast to move side to side didn't help.
Backstory: In late June of 1985 while owned by the previous owner, my DS II was apparently struck by lightning. The bolt went down the mast and exited through the bottom of the boat as far as I can tell. Part of the electric charge also travelled down the shrouds (not sure about forestay?) and the heat of the electric charge actually fused the strands of the cable (3/32") together at the point where they pass over the tips of the spreaders. One shroud snapped while under sail, I think the owner replaced the broken shroud (with 3/32" cable). but not the other side, which broke later due to the shock-loading caused by the loose rigging allowing the mast to sway as the boat rocked on the mooring.

However, my memory is unclear now as to the exact sequence of events and now I'm faintly recalling that he replaced the rigging at least twice...... So, the 1/8" rigging that is there now may actually be the 3rd set (original 3/32", replaced with 3/32", replaced again by 1/8").

But even if the looseness didn't cause any of the rigging failures, it certainly did not do it any good.
Rod Johnson, "SUNBIRD"
1979 DS II, # 10201
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Re: Tabernacle Mooring Question

Postby TIM WEBB » Tue Apr 26, 2016 10:39 pm

Everybody: listen to this guy^. He's been on here a long time, and pretty much knows what he's talking about.

SUNBIRD, it's good to see you checking in on the forum again!
Tim Webb
1979 DS2 10099 The Red Witch
(I used to be Her "staff", in the way dogs have owners and cats have staff, but alas no longer ... <pout>)
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Re: Tabernacle Mooring Question

Postby Alan » Tue Apr 26, 2016 11:09 pm

I'll second Tim's motion.
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Re: Tabernacle Mooring Question

Postby talbot » Wed Apr 27, 2016 2:51 am

Great! So Sunbird (or anyone), how tight is your rigging?

I have a non-graduated solid-side turnbuckle on the stay and Johnson graduated turnbuckles on the shrouds. I have the shrouds set at 3.5; no way to specify the tension on the forestay without a gauge, but the whole rig is pretty tight, and can't be pinned to the chainplates without using some purchase to flex the mast. The rig is canted aft. The boat originally had a lee helm, and I kept angling the mast aft little by little until the steering was neutral in moderate winds. In whitecaps, the boat heads up; in light air, it falls off.
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Re: Tabernacle Mooring Question

Postby DigitalMechanic » Wed Apr 27, 2016 8:03 am

Original aluminum rivets on the port tang failed, allowing my mast to go overboard one day during a gust ;)

Since I have replaced with SS rivets. 3/32 Shrouds were okay-ish, but I replaced to 1/8th to get the nicer turnbuckles, and "peace of mind". The original ones on the boat were in bad shape and made the boat very very difficult to adjust.
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Re: Tabernacle Mooring Question

Postby SUNBIRD » Wed Apr 27, 2016 1:01 pm

My rigging is set according to the Owners Manual suggestions: "After all stays are attached, take the slack out of the rigging by tightening all stays taut, but no more than hand tight." and "CAUTION: It is very important that you do not tighten the stays too much, as this can cause damage to the hull and deck. CAUTION: Be sure all lock nuts are securely tightened by pliers or a wrench and then taped to prevent loosening."

"Tuning: Do not overtighten stays, as mainsheet tension will dictate tension on Headstay. While sailing, the leeward stays will always go slack due to mast bend, stretching etc., so under no circumstances should you tighten them under sail. All adjustments should be made while at rest with the sails down. "

I basically make sure the mast is standing straight (not leaning to either side) and very slightly raked aft. Tension is "snug" as mentioned above, and I expect the leeward shroud to be slack, but not loose, while beating to windward. On the mooring The mast should not move as the boat rocks. If I pull on any piece of rigging the mast should move slightly in that direction.

Basically, I do it by feel and experience..... hard to exactly put it in numbers/words?
Rod Johnson, "SUNBIRD"
1979 DS II, # 10201
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Re: Tabernacle Mooring Question

Postby GreenLake » Wed Apr 27, 2016 2:21 pm

I had a friend bring a Loos gauge recently, and we double checked the tension based on a recommendation (also echoed by Roger) of something a bit over 200# (can't remember how much over, but I noted how many turns on my mast-jack, which is what matters to me for reproducing this).

The jack required a few more turns from before, but not unexpected, since the new shrouds and stay from last fall may not have been precisely the same length as the old ones (I got the kind that you adjust once, but don't readjust under load).

The result seems similar enough to the "by feel". I tighten to the point where it's just about possible to "strum" a note on the shroud. That tends to leave the leeward shroud between loose and slack depending on the wind. I remember that the "new" setting we worked out, ended up with rather similar feel.
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