Shroud plates...

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Slow_boat

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My Vivacity 20 doesn't have shroud plates but stainless 'u' bolts bolted through the deck for shrouds and back stays. They look like they're original equipment and there is no sign that shroud plates have ever been fitted nor any sign that they are stressed. I've seen this arrangement on another boat, I think it was an Albin Vega.

The thing is, I'm not sure if I trust them. There again, if they've lasted 40 years they should be okay.

Has anyone had experience of these things failing or any owners out there with a similar fitting that is okay?
 
You have answered your own question! The vivacity is an old design and you do not have signs of stress? I remember a Director of Ridgeway marine telling me (about a Pandora) if it's not broken why are are trying to fix it.

Regards.

peter.
 
Why shouldn't you trust them?

We have a Vega with the same type of fitting. You either assume they will last another 40 years, replace them or get them crack tested, I guess.

I have heard of a Vega forestay chainplate failing, but not a shroud fitting.

Don't know if this helps or not . . .

- Nick
 
Its the nuts underneath that crack open and fail if there is any ingress of water into the anaerobic (airless)area in the threads...You may find for example that in attempting to undo a nut to 'have a look'it simply falls into two halves...or is so seized that the threaded bit twists and snaps.
I would have good insurance or contemplate renewing..
 
I had U bolt on an 18 footer once.

I tried to unscrew the nuts from below for some reason. On one U bolt both nuts came off OK. On the other one did, but the other twisted off the end of the bold - it was hanging by about 1/8 of the bolt thickness. The remainder had corroded away. I have also heard stories of similar U bolts failing.

I alo have U bolts for the forward lowers on my Boomaroo 22 Jaguar 22). Recently, when I stupidly attacked an overhead wire with the mast the rig came down, and one of the U bolts snapped off both legs.

So, if I were you, I would replace them.


Ray
 
So after all these comments you probably have doubts. It would therefor be worth at least undoing the nuts. if new U bolts are available and not too expensive go for new ones.
If you have doubts about the stiffness or strength of the deck carrying the washers under the nuts of the U bolts it may be easy to fit 2 SS plates about 15mm wide 10 or more cms long with holes to take the bolts and holes at the other end. Use these plates bent at right angles (or nearly) are fitted one under each nut so that they come together. A shackle joins the other ends together and/or they can connect to a turnscrew in turn attached top a plate bolted through the hull or furniture or even to a larger plate glued to the inside of the hull. This will carry the stay loads down to the hull. Tighten the turnscrew so the hull just starts to flex downwards. This should take/share the load better than original. You could just have a tight fit and no turnscrew.
Of course you could fit larger diameter of metal U bollts. They can be squeezed together to meet the existing holes if it is the bolts you are concerned about.
I am not saying the original is bad, it really seems the project is to make you feel comfortable with the chainplate structure. Don't forget to renew the stays if they are over 15 yo. I must say when driving hard on my boat with 4 on the gunwhale I look at the stays and chainplate and wonder?
good luck olewill PS consider paralell additional U bolts and turnscrews perhaps a little inboard of existing ones. A shackle joins the top of 2 turnscrews to the stay.
 
The shrouds on a Virgo Voyager, a 23 footer, are fitted to U bolts. On mine there are 3 'U' bolts on each side. 2 for the lower shrouds and one for the upper. So the load is reasonably spread. The backstay goes to a chainplate fixed to the stern. No reason to suspect there are any problems and the boat is over 20 years old.
 
The trouble with U bolts is corrosion (crevice corrosion) when water starts getting down between them and the deck. We were probably lucky not to lose the mast of a Westerley Berwick a few years ago. One leg of one of them failed. We found the bit with the nuts on on the cabin floor before we noticed the fitting lifting off the deck!

Investigation revealed that those where there were small leaks were in a bad way. Another broke off while trying to undo the nuts. Ones which had been re-bedded some years previously were OK. I had done those because they leaked ino the locker in which I kept my clothes but the small leaks around the others did not cause any inconvenience so had been ignored. The one that actually failed was the worst leak but it was over the galley sink.

I would strongly advise that on a boat this old you should remove them for inspection and renewal if necessary. Be very critical of what you find and renew any suspect ones or renew them all for piece of mind anyway. Be particularly suspicious if there are any signs of leaks or corrosion on the legs of them as corrosion can lead to stress cracking which you won't be able to see by eye.

When we showed the bits to the yard owner he said that surveyors were aware of this problem and sometimes asked for one them to be removed for inspection. After seeing ours he said he thought perhaps they should ask for them all to be removed!

I think that is pretty much in agreement with tsmyth's observations.
 
I have U bolts on my Victoria as do all the Victorias and Frances, even the larger boats. My surveyor was surprised that they were used on a boat rumoured to be capable of going anywhere. I have noticed from pics of earlier American boats that they have proper steel plates. However my U-bolts have serious reinforcement in the way they are bonded to bulkheads. I did remove one that was weeping a little, but there was no corrosion so just rebedded it with a healthy dose of sealant. I would check and replace any corroded bolts and stop worrying unles you are planning to go trans-atlantic.
 
My boat uses U-bolts and they are over 40 years old as well. Strength is not an issue under the loads we put on them. As Vic says, crevice corrosion is the killer, so pay heed to any leaks and re-seat them if any dripping or rust staining is detected below decks.
 
First thing is check deck around the U bolts ... is it crazed or cracked. This would indicate movement and possible leading to later failure as the fitting pulls through.

If you notice light crazing .... then recc'd remove underdeck fastenings and fit a larger backing plate..... possibly with somne extra resin and stiffening matt.
Often they were fitted with only the silly small plate or "penny-washers" .. which don't have really enough surface area to spread the load.

If there is no sign of crazing etc. then you are most likely ok - I have same fitted through raised GRP toerail :>

s-anne05-07-02.jpg


Mine have very limited backing as the toerail I cannot even get fingers up there ! So when I need to repair etc. - such as the mooring cleats on the rail - I use studding passed down through, large washer and doulble locked nuts .... after passing studding down till exits into cabin ... pull washer / nuts on studding up into rail and wind nut on from outside to complete. Cut off excess studding.
 
I have this problem on my Westerly Pageant. The side decks show no cracks or crazing but are noticably being pulled upwards. As recommended, I'm about to replace the penny washers beneath with some ss plate - do you think I'll be able to tighten the bolts so the deck pulls down level again if I do it very carefully?
I thought about packing underneath so the distortion remains, but a future suveyor might think the problem is still there.
Any suggestions?
 
Hard to say without seeing it. Does it go back down when the rigging is slackened?

Personally if the deck is undamaged I would fit a long as possible piece of 12mm plywood under the deck and a stainless bar under the ply.drill and Bolt through the whole lot .Use seakaflex or similar sealant.

The Westerly Owners association may be able to help if other Pageants have needed the same repair.
 
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