Boat Gone Adrift.

[lw395]

I also think a lot of people are very casual about doing up shackles.
You wouldn't tighten a M20 bolt with a little spanner, you'd torque it up with a big spanner...

 

[LadyInBed]

Because the cause of the original failure was self evident, and was dealt with by shortening the riser which years later was in perfect condition when changed again. Ten years later when the boat pulled the mooring block in a force 11 storm, again the cause of the failure was self evident and this was dealt with by adding a bigger weight, and an additional anchor,

Pity that you didn't mention that in the OP!
I would say:
Dragging 6%
Broken Riser 2%
Swivel 10%
Mooring Eye 2%
Strops 10%
SHACKLES 70%

 

[PlankWalker]

In 40 years on a swinging mooring on which I am responsible, she's gon walkabout twice, and survived the 87 storm.
20 years ago the underwater swivel failed. I now use a hipo buoy with the swivel in fresh air.
2 years ago the shackle at the bottom of the riser failed, never found it so I dont know how. I use 35mm strop with hose and thats never going to chafe on an 8 tun boat
I woud be interested to know if twice in 40 years is excessive or par for the course?

Plank

 

[lw395]

....
I woud be interested to know if twice in 40 years is excessive or par for the course?

Plank

Excessive I'd say.
That would be equivalent to dozens of yachts going wild every year in Portsmouth Harbour and it's thankfully very rare.

I agree about swivels though.
I find if you have a swivel just under the buoy, it's not too hard to lift the riser at low water, using a handy billy tackle from the bow roller, capsize the buoy and check the swivel.

 

[pandos]

In 40 years on a swinging mooring on which I am responsible, she's gon walkabout twice, and survived the 87 storm.
20 years ago the underwater swivel failed. I now use a hipo buoy with the swivel in fresh air.
2 years ago the shackle at the bottom of the riser failed, never found it so I dont know how. I use 35mm strop with hose and thats never going to chafe on an 8 tun boat
I woud be interested to know if twice in 40 years is excessive or par for the course?

Plank

Thanks for that reply, that and others like it is exactly the type of first hand knowledge that I was hoping to get. I have spoken to many over the years who have had boats go adrift for various reasons.

Perhaps by time this thread dies we will have an answer to the question you posed....

Is twice in 40 years excessive?

Tony.

 

[lw395]

....

Perhaps by time this thread dies we will have an answer to the question you posed....

Is twice in 40 years excessive?

Tony.

It's a lot per boat.
I would guess a boat going walkabout could easily do £10k of damage to itself, cost several £k in hoiking it off the mud/rocks, maybe damage other boats, get in the way of shipping etc etc.
When it's one boat in 10,000 per year, our insurers want our business.
When it's one in 20, they won't.

I don't mean to criticise the one bloke here in many hundreds who's been unlucky BTW.

Stuff wears out and breaks randomly, but we have to engineer that out as much as we possibly can.

 

[pandos]

I don't mean to criticise the one bloke here in many hundreds who's been unlucky BTW.

Theres more than one bloke here who has been unlucky, I had two occurrences.

and I know of two others who had similar, both of those were caused by lack of maintenance where the swivels parted.

In none of these 4 cases was any damage done, or any cost to insurers...

Tony

 

[Seajet]

My chum's E-Boat was moored with a rope strop, in a place between 2 concrete bridges.

He's a very experienced sailor, and a good pro' engineer; a series of severe gales hit and he knew he needed to get out and check her, but it was quite unusual weather ( late Autumn but still the summer season, I seem to remmeber ) - he was simply unable to get out there safely in a tender.

Years ago I suggested an experienced team could go around in a club rescue boat when gales are in the offing, checking moorings as much as possible, ensuring roller headsails are tightly secured etc, but this was poo-poohed on liability grounds, whether that is a real concern seems dubious to me...

Anyway sadly the rope strop chafed through and she was toatally wrecked; it was a horrible sight, and very upsetting to chum, as it would be to any sailor who cares about their boat as more than just £ signs.

Incidentally re ' tightening shackles with a big spanner ', care should be taken, it's quite easy to strip the thread of even a big shackle; positive locking like wirelocking ( mousing ) is essential, and I am beginning to think of having aircraft style split pinning as well as mousing.

 

[lw395]

....Incidentally re ' tightening shackles with a big spanner ', care should be taken, it's quite easy to strip the thread of even a big shackle; positive locking like wirelocking ( mousing ) is essential, and I am beginning to think of having aircraft style split pinning as well as mousing.

Mousing has been shown time and time again to be unreliable.
Particularly if your mooring is in an area where sailing schools choose to practice lassoing.
I think the shiny shackles from chandlers might be more easily stripped than the certified ones?
The only ones I've stripped have been where I've changed the pin for a bolt, but good point to be aware of.

 

[GrahamM376]

Where we're based, all moorings are privately owned and most don't get serviced. Of the many failures I've seen, most have been chain rusting through, next is shackle pins corroding around the threads and falling out and lastly, the minority, failed swivels. Dragging of the lighter ones is also a problem when idiot visitors with heavy boats pick them up without knowing what's on the bottom.

 

[Seajet]

Mousing has been shown time and time again to be unreliable.
Particularly if your mooring is in an area where sailing schools choose to practice lassoing.
I think the shiny shackles from chandlers might be more easily stripped than the certified ones?
The only ones I've stripped have been where I've changed the pin for a bolt, but good point to be aware of.

There's mousing and there's mousing !

Wire-locking is good enough for important bits of aeroplanes such as control linkages, but there is a very definite way to do it, and of course inspectors who know the procedure come along afterwards and check.

Luckily I trained at that with Hawkers / BAe, but in the marine application it's only common sense; monel wires twisted together and 'pulling ' - so as to tighten the thread, or ' oppose undoing ' if one looks at it the other way.

I have never known a properly seized / moused / wirelocked shackle come undone, but with moorings I do usually apply 3 separate wire lockings at each point; ' Paranoid, Moi ? ! '