Has anybody any thoughts as to the 'rip out' loads for the main anchor bollard and the forward cleats. Given the Sabre can weigh 3.5 tonnes plus, I am guessing they will not be insignificant? Is there a formula, perhaps, that might help?
Thoughts please?
Loadings - Anchor bollard and cleats
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ken endean
- Posts: 42
- Joined: Wed May 10, 2017 11:11 am
Re: Loadings - Anchor bollard and cleats
Prof. John Knox did a lot of research on anchor loads, including load cell tests, and came up with the formula:
Force (kg) = wind speed (kn) squared x length (m) squared divided by 500. Obviously, it is an approximation but it is more logical then it looks because effective width (when the boat sheers) and effective height can both be treated as functions of the length.
Knox was primarily interested in anchor performance; mooring warps to a quay have less sag/stretch than anchor chains and will experience higher peak loads. In any case, you will want a generous factor of safety on anything that could tear out of a deck.
On the other side of the pond, US sources often quote ABYC (American Boat and Yacht Council) loads and you can find them on the web.
Force (kg) = wind speed (kn) squared x length (m) squared divided by 500. Obviously, it is an approximation but it is more logical then it looks because effective width (when the boat sheers) and effective height can both be treated as functions of the length.
Knox was primarily interested in anchor performance; mooring warps to a quay have less sag/stretch than anchor chains and will experience higher peak loads. In any case, you will want a generous factor of safety on anything that could tear out of a deck.
On the other side of the pond, US sources often quote ABYC (American Boat and Yacht Council) loads and you can find them on the web.
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samphire2014
- Posts: 66
- Joined: Tue Jul 18, 2017 12:47 pm
Re: Loadings - Anchor bollard and cleats
Thank you very much. Certainly food for thought and much more than I had hoped for 