[Swingshiftworker]

What is a minimum thickness of chain that one should use out on the trail? Would it come in handy much for recovery/rescues???

A 3/8" Grade 70 transport chain is pretty standard. A 5/16" Grade 70 chain only has a WLL of 4700 lbs (2.35T). A 3/8" Grade 70 chain has a WLL of 6600 lbs (3.3T) and is better matched in strength to a 8k-9k lb winch and a 3/4" D-ring (WLL 4.75T). The chain slot on the Xtreme Hi-lift accessory and the JackMate are also sized for a 3/8" chain.

Don't know anything about the "marine" HT (high test) chain skorp62 is recommending, but if you look at the following chart, you'll see that 3/8" Grade 43 HT chain has a lower WLL than 3/8" Grade 70 and that only a 3/8" Grade 100 alloy chain, which is primarily designed for lifting loads, would actually match the weight limits of a 8-9k lb winch and a 3/4" D-ring: Chain Specifications

You can buy a 3/8" Grade 100 chain here. I already have a Grade 70 chain, which cost $95 from Expedition Exchange. The Grade 100 chain costs about twice as much and is obviously "better" than a Grade 70 chain in terms of strength, but it's not clear how much you'll really need a chain of that grade. Only you can decide that.

 

[Swingshiftworker]

If my memory serves me, all recovery equipment used should be rated higher then the tool doing the work. In other words your winch and/or Hi-Lift jack should be the weakest link in the pulling cascade. Just think about what would you want to let go in a break-certainly not any chain, hooks, or clevis's.

I don't think that's the case.

Bill Burke has a DVD in which he uses a Hi-lift jack, Hi-lift jack winch adapter and tensioner, a 3/8" chain, 3/4" D-rings, a tree strap, a 2" recovery strap and a Amsteel blue winch line extension in order to hand-winch a vehicle over flat terrain with a Hi-lift jack. The Hi-lift was the weakest link at only 5k lbs, which is consistent with your theory.

However, there's also a segment in the video in which Burke uses a 3/8" chain along w/D-rings and a tree strap as an anchor around a boulder for a snatch block so that he can double-line pull his Land Rover up over an obstacle at least 6 feet high. The chain was the weakest link in this case at 6.6k lbs and the tree strap was probably the strongest. The winch (the "tool" doing the work) was probably rated at 9k lbs, in between the two other pieces of recovery gear.

The latter demonstration contradicts the theory that you should only use recovery gear that has a higher WLL than the "tool" doing the work and makes the case (which is the mostly logically intuitive) that you simply need to avoid exceeding the WLL of the weakest piece of equipment being used.