2 issues; all personal preference for your type of diving.
Caveline can be tightened so you only have 1 pivot between the boltsnap and your light. A metal split ring creates 2 pivots on either side of the ring.
If you keep your light attached to a strap or D-ring, then these pivots can become an annoyance, or it could allow for easier positioning of your light.
I personally find it an annoyance. Sometimes the pivots lock up in a twist and I have to flick my wrist to get the light to angle a certain way. With caveline, it's easier to control. When you have the light unclipped, the ring+boltsnap can also create a noisy and annoying dangly that clinks with your light.
The second issue is safety. Should your light become entrapped, caveline gives you the ability to cut away. In an open water environment this isn't really an issue at all. You still have your boltsnap to release. In a cave or wreck however, you may not be able to reach and release your boltsnap, which is why caveline is recommended in this situation.
If you do go with metal, you should get quality stainless steel. A lot of hardware stores sell just plain steel, but you can still find stainless steel there as well. It will generally be labeled and be the more expensive version on the shelf.
If you go with caveline, #24 or #20 will do. Finely file down you light's lanyard hole if it doesn't come with slightly round corner already. This will keep your caveline from tearing prematurely. I've found that in these types of applications, you rarely have to replace caveline due to wear.
Tutorial on how to properly tie caveline:
- add a dab of aquaseal, neoprene cement, or gorilla glue and your knot is definitely not coming undone.
http://www.wreckandcave.co.uk/2006/11/11/how-to-tie-the-perfect-boltsnap/
Caveline can be tightened so you only have 1 pivot between the boltsnap and your light. A metal split ring creates 2 pivots on either side of the ring.
If you keep your light attached to a strap or D-ring, then these pivots can become an annoyance, or it could allow for easier positioning of your light.
I personally find it an annoyance. Sometimes the pivots lock up in a twist and I have to flick my wrist to get the light to angle a certain way. With caveline, it's easier to control. When you have the light unclipped, the ring+boltsnap can also create a noisy and annoying dangly that clinks with your light.
The second issue is safety. Should your light become entrapped, caveline gives you the ability to cut away. In an open water environment this isn't really an issue at all. You still have your boltsnap to release. In a cave or wreck however, you may not be able to reach and release your boltsnap, which is why caveline is recommended in this situation.
If you do go with metal, you should get quality stainless steel. A lot of hardware stores sell just plain steel, but you can still find stainless steel there as well. It will generally be labeled and be the more expensive version on the shelf.
If you go with caveline, #24 or #20 will do. Finely file down you light's lanyard hole if it doesn't come with slightly round corner already. This will keep your caveline from tearing prematurely. I've found that in these types of applications, you rarely have to replace caveline due to wear.
Tutorial on how to properly tie caveline:
- add a dab of aquaseal, neoprene cement, or gorilla glue and your knot is definitely not coming undone.
http://www.wreckandcave.co.uk/2006/11/11/how-to-tie-the-perfect-boltsnap/
