Viewing every one of those pics, here at a boring day at work, was awesome.
It looks as though most of them had a turning block attached to the front trap line, that the jib sheet runs through, right?
More likely to be the downhaul (cunningham), routed from the cleat at the mast base to a turning block of the crew trap and then back onto the boat with the end kept under control with a bugee (e.g. in the front cross bar). This lets the crew and/or skipper have ready access to the downhaul when going to weather.
Chris.
