Maximum Weight On Buoy Is It A Problem?

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dewent

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Our boat weighs around 12 tonnes. In the cruising guides buoys are often marked with maximum weights - 5 tons is common in the Irish Sea area we cruise in. Whilst not wanting to be dragged away when asleep on a mooring buoy can these limits be safely ignored in good/reasonable weather?
 
In that case I'd think in real life it would be fine in decent weather, but it won't be much use quoting me on that if something goes wrong !

In heavy weather I'd be a bit worried, but it would probably still be safer than anchoring, if a heavier grade mooring wasn't available.

As I say, if something did go wrong, say in heavy weather, insurance might use it as an excuse not to pay up ?
 
My boats 13tons and I quite often get directed to buoys marked well below that weight by harbour masters. Its fine in light conditions where your not putting any strain on the gear, but in strong winds I'd probably be inclined to either find somewhere else or trust my ground tackle.
 
Seajet said:
In that case I'd think in real life it would be fine in decent weather, but it won't be much use quoting me on that if something goes wrong !

In heavy weather I'd be a bit worried, but it would probably still be safer than anchoring, if a heavier grade mooring wasn't available.

As I say, if something did go wrong, say in heavy weather, insurance might use it as an excuse not to pay up ?
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What on earth makes you think that a mooring rated for 5 tons would be safer than a 12 ton boat's own anchor?
 
Daydream believer said:
We often get overweight boats on small yacht moorings
Creates havoc as it often breaks the sinker free & they drag
Some people seem oblivious of size stated on the buoy
Basically pig ignorant really
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In fair weather, without a sea running through the moorings, there ought to be a pretty big margin for safety.
As soon as there is chop running through the harbour, a heavy boat can do a lot of damage if it is allowed to lurch or surge on the mooring.
But you would not want to be aboard a boat that is moving violently enough to shift even a 1 ton sinker, or break a 6mm chain.
Sometimes a heavy boat will sit still and put less jerking loads on a mooring, while light boats are thrown around and pulled up short by the chain.
Some people do tae the mck though, our club has some moorings only intended for one tonne dayboats, a yacht will lift the gear very easily.
It's up to the owner of the mooring where to draw the line.
 
If a buoy says 5 tons it is for a reason. A 12 tonne boat should never use a 5 ton rated mooring. You may well lift the sinker or strain the ground tackle. If a lift says max 12 persons would you be happy to put 24 in it?
dewent said:
Our boat weighs around 12 tonnes. In the cruising guides buoys are often marked with maximum weights - 5 tons is common in the Irish Sea area we cruise in. Whilst not wanting to be dragged away when asleep on a mooring buoy can these limits be safely ignored in good/reasonable weather?
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are the bouys marked ton or tonnes?

5 ton or 5 tonnes.?
big differance.

a ton is a mesurment of internal volume 1 ton= 100 Cubic ft

A 5 ton boat has a Volume of 500 cubic feet quite big.
A 5 Tonne boat has a displacement of 5000 Kg.

My old IOR 35 is less than 1 ton about 3/4 but at 10200 lbs just under 5 Tonnes.

While it may seem I am just being pedantic. Im not intending.
The strain on the mooring in strong wind from a low displacement high volume boat may well be greater than the strain from a high displacement low volume boat.

In ither case I would sugest it is not advisable to exceded the rating of the bouy. just be sure what it is rated for.
 
dewent said:
Our boat weighs around 12 tonnes. In the cruising guides buoys are often marked with maximum weights - 5 tons is common in the Irish Sea area we cruise in. Whilst not wanting to be dragged away when asleep on a mooring buoy can these limits be safely ignored in good/reasonable weather?
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If the boatyard were lifting your boat with a crane certified at 5 tonnes max, would you be happy? Even allowing for the built in safety margin? Well moorings are no different even if you will likely get away with it in a flat calm.
 
Bearing in mind the poor holding in most IOM visitor buoy areas I'd be very worried about having to move off in bad weather and have no where near to drop the hook. The seas around the Island get vvvvv rough so I wouldn't trust it for anything other than a lunch stop.
 
dewent said:
Our boat weighs around 12 tonnes. In the cruising guides buoys are often marked with maximum weights - 5 tons is common in the Irish Sea area we cruise in. Whilst not wanting to be dragged away when asleep on a mooring buoy can these limits be safely ignored in good/reasonable weather?
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Look at what you're asking from another direction, if your home mooring is marked 12 tonne and you find a visitor with a 28 tonne boat using it, how pleased would you be? or are you a marina berth holder that expects private mooring holders to let over sized vessels use their gear while they are away? common sense and good manners play a major part on this subject.
 
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Remember a 1 metric tonne sinker does not effectively weigh 1 tonne when it is in water as it is partly supported by the water it displaces
Specific gravity & all that

As for an imperial ton - i thought that was 2240 lbs, not thin air
 
It depends on the depth and the general set-up, but in a perfect world a sinker will be lowered into a dug hole, not simply plonked on the seabed; if it is just plonked, I'd certainly rather anchor in strong winds.
 
Daydream believer said:
Remember a 1 metric tonne sinker does not effectively weigh 1 tonne when it is in water as it is partly supported by the water it displaces
Specific gravity & all that

As for an imperial ton - i thought that was 2240 lbs, not thin air
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The orogin of the imperial ton was the tun the biggest sise of wine barrel which weighed arround 2240 lbs. and was about 100 cubic feet. vessels have been comonly desribed by tonnage in which uses the volume referance of 100 cubic ft per ton and is still in common use.
I thought the UK Including the IOM went metric for weights and mesurments about 44 years ago.
although many boats built back in the 60s or prior would be imperial.

I would have thought moorings laid in recent decades would be by tonnes.
If marked in tons I would wonder if they were refering to tonnage rather than displacement.
 
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