30-09-2021, 12:40
@jacques-2 Se passa nella catena il carico ci sarebbe, ma temo si possa tagliare dopo qualche ora.
Manually tying the line to the chain with a rolling hitch is suggested as a preferable alternative to a chain hook. This does not stress the chain as much as a hook can. A rolling hitch, which retains most of the strength of the rope, takes a little longer to attach and remove, but does not wear the chain and tends to spread the load over multiple links of chain. Tie the rolling hitch around the exterior of a link of chain, then secure the working end with one or two clove hitches further down the chain. The clove hitches have no need to be tightened.
A chain hook can also be another 'weakest link' factor in the system, as some claw types made out of bent bar will open up under strain. Often the rope is spliced directly through the hook eye, which then forms a weak point – rather, it should be spliced through a thimble and joined with to the hook with a shackle (which in turn can be a weak point and should be of maximum quality). Bear in mind that chain hooks can place adverse strain on a single link of chain in a direction for which the chain was not designed. Additionally, a metal claw working on a chain link is hard on the galvanizing and will result in substantial wear.
Rope used as a dedicated snubber should be sized according to the conditions and the vessel. In general a minimum of 10 m (30') should be employed, or a length of half the LOA of the vessel, whichever is longer. A shorter snubber (depending on the rope diameter) does little with regard to shock absorption.
Manually tying the line to the chain with a rolling hitch is suggested as a preferable alternative to a chain hook. This does not stress the chain as much as a hook can. A rolling hitch, which retains most of the strength of the rope, takes a little longer to attach and remove, but does not wear the chain and tends to spread the load over multiple links of chain. Tie the rolling hitch around the exterior of a link of chain, then secure the working end with one or two clove hitches further down the chain. The clove hitches have no need to be tightened.
A chain hook can also be another 'weakest link' factor in the system, as some claw types made out of bent bar will open up under strain. Often the rope is spliced directly through the hook eye, which then forms a weak point – rather, it should be spliced through a thimble and joined with to the hook with a shackle (which in turn can be a weak point and should be of maximum quality). Bear in mind that chain hooks can place adverse strain on a single link of chain in a direction for which the chain was not designed. Additionally, a metal claw working on a chain link is hard on the galvanizing and will result in substantial wear.
Rope used as a dedicated snubber should be sized according to the conditions and the vessel. In general a minimum of 10 m (30') should be employed, or a length of half the LOA of the vessel, whichever is longer. A shorter snubber (depending on the rope diameter) does little with regard to shock absorption.
