mick
Well-Known Member
What is the safe working load of 8mm galvanised chain? I'm assuming the chain is of good quality.
Chain SWL
- Thread starter mick
- Start date
rob2
Well-Known Member
Jimmy Green's website gives the breaking strain as around 3.2 tonnes...
I guess for SWL you would halve that?
I guess for SWL you would halve that?
Mariner69
Well-Known Member
The old seamans way of finding the safe working load is done in two steps. First find the breaking strain in tonnes: calculated by 30(D^2)/600 where D = dia of rod making the chain in millimetres. Second the safe working load (SWL) is 1/6th of BS. So BS=(30*8*8)/600 =3.2 tonnes. Divide by 6 for safe working load and you get 533 kg SWL. Smaller safety factors can be used where the loads are only for sideways motion; the seaman's safety factor of 6 is for lifting (legal requirement SF=5) to ensure no disaster.
mick
Well-Known Member
[ QUOTE ]
The old seamans way of finding the safe working load is done in two steps. First find the breaking strain in tonnes: calculated by 30(D^2)/600 where D = dia of rod making the chain in millimetres. Second the safe working load (SWL) is 1/6th of BS. So BS=(30*8*8)/600 =3.2 tonnes. Divide by 6 for safe working load and you get 533 kg SWL. Smaller safety factors can be used where the loads are only for sideways motion; the seaman's safety factor of 6 is for lifting (legal requirement SF=5) to ensure no disaster.
[/ QUOTE ]
Good God! Does that mean any load on my 8mm chain above 500 kg and I'm taking a chance?
The old seamans way of finding the safe working load is done in two steps. First find the breaking strain in tonnes: calculated by 30(D^2)/600 where D = dia of rod making the chain in millimetres. Second the safe working load (SWL) is 1/6th of BS. So BS=(30*8*8)/600 =3.2 tonnes. Divide by 6 for safe working load and you get 533 kg SWL. Smaller safety factors can be used where the loads are only for sideways motion; the seaman's safety factor of 6 is for lifting (legal requirement SF=5) to ensure no disaster.
[/ QUOTE ]
Good God! Does that mean any load on my 8mm chain above 500 kg and I'm taking a chance?
wotayottie
Well-Known Member
On a 26 footer I would be very surprised if the cleats would stand a pull of 500 kg. The load on your anchor chain would be far less than this.
pampas
Well-Known Member
no. You are not lifting you boat, if so your mooring lines would be huge. /forums/images/graemlins/grin.gif
gandy
Well-Known Member
These guys give "working load limit" figure of 800kg for 8mm grade 40 chain
http://www.bradneychain.com/_pdf/short_link.pdf
http://www.bradneychain.com/_pdf/short_link.pdf
MM5AHO
Well-Known Member
What grade of chain are you asking about?
The SWL depends on the grade as well as the link diameter.
Bit like asking "Whats the horsepower of a car, a biggish one?" /forums/images/graemlins/ooo.gif
The SWL depends on the grade as well as the link diameter.
Bit like asking "Whats the horsepower of a car, a biggish one?" /forums/images/graemlins/ooo.gif
Salty John
Well-Known Member
Working Load Limit (WLL) is 800kg for 8mm DIN766 short link chain. Ultimate breaking strength is 3200kg
It will hold a 40' boat in hurricane force winds without exceeding the WLL - as long as the anchor stays set!
It will hold a 40' boat in hurricane force winds without exceeding the WLL - as long as the anchor stays set!
mick
Well-Known Member
[ QUOTE ]
Working Load Limit (WLL) is 800kg for 8mm DIN766 short link chain. Ultimate breaking strength is 3200kg
It will hold a 40' boat in hurricane force winds without exceeding the WLL - as long as the anchor stays set!
[/ QUOTE ]
That's what I want to hear, as my chain meets that specification. Difficult to guess what sort of load you're experiencing in strong winds. Thanks to all.
Working Load Limit (WLL) is 800kg for 8mm DIN766 short link chain. Ultimate breaking strength is 3200kg
It will hold a 40' boat in hurricane force winds without exceeding the WLL - as long as the anchor stays set!
[/ QUOTE ]
That's what I want to hear, as my chain meets that specification. Difficult to guess what sort of load you're experiencing in strong winds. Thanks to all.
