Originally Posted by Capt.Bill11
Exactly! Using a line with little or no stretch defeats one of the main purposes of using a snubber.
The soft shackles are only a few inches long. They are used as a means of attaching the nylon snubber to the chain. As you point out, Dyneema is no good as a snubber. It needs to be nylon for the stretch. Evans Starzinger, who I think initially came up with idea of using soft shackles for this purpose, has done some work on creating the ideal snubber. It consists of some Dyneeema used where the line goes over the bow roller. Dyneema has fantastic chafe resistance which is ideal for this role. This is followed by a long length of nylon for the necessary stretch connected to the chain via a soft shackle. You can of course rig the same idea as a bridle if this is applicable for your boat.
The "ideal" snubber is overkill for most applications, but it has a lot of merit for extreme conditions. The main drawback is that adjusting the snubber length is difficult.
While on the subject of extreme conditions the use of two independent snubbers is worth considering. With one left slight loose as a reserve. Chafe is very good at eating away through nylon. If you are using a small diameter snubber, as you should be, there is little strength margin for even small amounts of chafe. A broken snubber particularly if there is loop of chain will cause the boat to come to a very abrupt stop if the boat gathers a bit of momentum and is stopped by the non elastic chain.