Net cutters?

[Didd]

Anti-sub nets were made of steel (they rust!) - at least around Orkney they were. There are a few left lying around on beaches here and the Naval museum at Lyness on Hoy has a fence made of the stuff. From memory I'd say the links are approx 16" dia made from approx 1/2" dia very coarse wire rope. Each strand is maybe 3mm dia (again from memory) with just a gentle twist on the bundle. There is very little flexibility in a link. Look as I might, I have never yet found a join in one of the links (if that makes sense) but there must be a weld somewhere....

I really struggle to see a wee serrated thing on the front of a sub doing any more damage that a superficial scratch.

Didd

Edit: By chance I have a photo that includes the fence at Lyness museum if anybody is interested. Also in the shot is a torpedo which appears to be heading straight for the camera and one of the screws from HMS Hampshire which was sunk by a mine in WW1 just a mile or two from my front door. If anybody wants to see it let me know and I'll try and work out how to!