In one of my sailing books, I have a few small sailboat rigging diagrams. Both of these show something that looks like clamcleats mounted near or at the shroud/turnbuckle chain plates. Although I'm not sure as it's a line drawing image and smaller details are a bit unclear. These have something to do with the spinnaker sheets, but I'm not sure exactly what they are or how the are used. Can anyone tell me what a reaching hook is? I thing this book may have been originally publish in the UK so there may also possibly be a different term in the US for these.