Pic 63: The first standing rigging. This is the structural rigging that supports the masts and bowsprit and was not moved during a voyage. The threads must not sag, but if they are pulled too tight - and it's easy to do - the masts will be pulled out of position. This particular thread is quite complex so it's being fixed in stages, with a tiny dab of glue where it passes through the dolphin striker. The clips are keeping just enough tension on the line.
Note: Rigging can seem intimidating, and the San Juan has a fair amount, especially shrouds and ratlines. But just as a journey of a thousand miles starts with a single step, take the rigging one line at a time and eventually you'll finish it. The usual rule is to start from the inside and work upwards and outwards - that way you don't obstruct yourself later. The order is usually: stays - shrouds - ratlines - backstays - yards - running rigging.