Warning - please read.

wooslehunter

wooslehunter

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Close to the hard where I launch my tender was a 30ish foot yacht drying out against the quay wall.

I was just getting SHMBO & the kids out of the dinghy last night when there was an almighty bang as the warps parted and the yacht fell over. I'd hate to think what would have happened if anyone was close to it. The weight of the yacht must have been on the warps rather than leaning against the wall.

Unless you are absolutely sure of the security of a dried out yacht, don't go near it. The consequences could be dire.

This sounds obvious but what I saw just goes to show how some things happen.
 
can you confirm where this was. whats the sea bed like does it slope. or did the chap just get it badly wrong. glad now one was hurt it could of been nasty
 
For my 32 footish fin keeler, anything more than about 3-4 deg. inward heel would take the entire crew on the outer side deck without any movement.

I always attach to land using a bowline round the mast. I can't imagine what it would take to cause a topple.

Your example must have been near or beyond vertical and been without a safety line or well organised breast ropes, which should also be present to prevent total topple. Was it just secured by the long fore and aft ropes I wonder, which may have had enough stretch to allow it to tip too far out?
 
I saw it the other way once at Conwy. a BIG (possibly ferrocement) yacht had fallen INWARDS towards the quay. Guard rails and stanchions all smashed and the shrouds all snapped. Amazingly, the mast was still in 1 piece (albeit with quite a bend in it!) but I'm not sure how much of the boat's weight was being taken by the gunwhale against the harbour wall and how much was being taken by the mast.
 
Sea bed is flat and concrete with around 18" of water over it at the time the yacht fell. Didn't see any mast ropes & I would not have used the warps that broke for normal mooring.

Just a note of warning now I'd guess quite a few are contemplating a mid season scrub.
 
Re: Warning - please hava larf!

Cruising the Channel Islands in a Westerley wotsit (31ft, fin keel, sloop rig, aft cabin) we dried out in St Aubin keeping clear of the St Helier ratpack. Stayed several days, stb'd side to, no hassle with line ashore from block sliding up/down main halliard.

On second night turned in, me on long saloon berth to port, heavy crew on portside of foc'sle, heavy girl on port berth aft. The other two? Canoodling in the cockpit.

Sudden bang, halliard sheave explodes, all fall down, about 50 degrees into the mud. Hasty rearranging of apparel by courting couple!

Go on, tell me the moral of THAT if you please!
(Apologies to CA members who know the full story.)
 
Re: Warning - please hava larf!

Perhaps it was the same effect as Galloping Gertie, the bridge made famous by physics teachers everywhere.

See here

For years, the theory has been that wind caused vortices to be shed from the bridge. Each time a vortex was shed, the bridge was given a slight kick up or down. At the critical wind speed, the vortices were shed at the correct frequency to cause the bridge to resonate and the oscillations to build up until eventually, the bridge collapsed.

However, in light of your evidence, I'd like to offer an alternative theory. In your case, I'd guess that the lines were perfectly capable of hanlding the loads. However, excessive "canoodeling" in the cockpit at the critical frequency could easily have set up a resonance in the boat. This would have caused the weekest link, the sheeve, to explode an thus cause the boat to fall.

If you look very very closely at the film clip, you will see a small car on the bridge. I suggest the an unfortunate couple may have been "canoodeling" very excessivly in the car at the correct frequency to set up the resonance. Clearly, as in the case of the couple on your boat the earth truely did move.
 
Re: Warning - please hava larf!

That's fightin talk that is.

Google "Tacoma Narrows" = 391000 hits.
Google "Tacoma Straights" = 10 hits
Google "Tacoma Straits" = 99 hits.
 
Re: Warning - please hava larf!

They must have had a larger cockpit than mine, and somewhat more clear!

I don't think anyone could get up to anything out there without the aid of a thick mattress, and short legs!! Suppose they could not have used a mattress or it would have absorbed sound etc. when they started to "resonate" together?

There again they could just have been younger and more animalistic!
 
Re: Warning - please hava larf!

___________________

"heavy girl on port berth aft"
___________________

Are you absoluely sure she doesn't read the forum, otherwise you are a dead man walking
 
pickle.jpg


These warps must have been creaking a bit. /forums/images/graemlins/grin.gif
 
Re: Warning - please hava larf!

[ QUOTE ]
we dried out in St Aubin keeping clear of the St Helier ratpack. Stayed several days, stb'd side to, no hassle with line ashore from block sliding up/down main halliard.

On second night turned in, me on long saloon berth to port, heavy crew on portside of foc'sle, heavy girl on port berth aft. The other two? Canoodling in the cockpit.

Sudden bang, halliard sheave explodes, all fall down, about 50 degrees into the mud. Hasty rearranging of apparel by courting couple!


[/ QUOTE ]

Kinda sorry I missed that, at least you had a soft landing!

I won't laugh, I ran aground in the St Aubin's Pier heads this year...........local knowledge my ar#e!!
 
Re: Warning - please hava larf!

The photo looks alarming, but surely once the ropes to the masts are secured the force on the masts and rigging will be no more than that required to heel the boat at that angle in a strong wind? Don't they say that as a rule of thumb the shrouds on one side of a boat should have a breaking strain equal to the weight of the entire boat?
 
Re: Warning - please hava larf!

They do, but I'm not sure of the wisdom of that statement, althoguh it strikes me as a good rule to follow anyway. The force exerted on the mast by the wind to heel the boat when sailing is equal to the righting moment of the boat when heeled, whereas the force exerted on the mast be a boat hanging off like that is ... hang on .. I reckon it's the weight of the boat times the sine of the angle of heel. Both operate on the mast with the same lever arm, but whereas one pivots around the CoB, the other pivots arpound teh foot of the keel. Afloat, the lever arm of the centre of buoyancy and centre of gravity can never be longer than half the beam, canting keels aside. But once a boat leaning out from a wall heels beyond a few degrees, i.e. to the point where the horizontal distance from keel foot to CoG is greater than half the beam then I think the forces will exceed those experienced when afloat. Unless anyone knows different.
 
Re: Warning - please hava larf!

That sounds true. What about careening ships in the old days? Weren't they beached, then hauled right over on their sides with tackles to the foot of handy palm trees?
At the point when the situation in the photograph became apparent as the tide fell, would it have been better to secure ropes to the masts, as the crew clearly did, or let the ship go right over on her side? The ground appears to be reasonably horizontal, not shelving, which if steep I can see would be a disaster.
 
Re: Warning - please hava larf!

I'm not sure they cut things quite so finely as racing yacht builders would these days. Rather than calculate what the rig would withstand, often without the benefit of a slide rule, they would over-engineer it on the basis of experience and then add a bit for luck. Or else just build it as big as was sensible, or using the biggest stock they had, so that it "looked right". Mind you, some of the tales of the tea clippers would probably show that risk taking and hairy sailing is nothing new.
 
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