Just purchased a 1986 P-18. I was parking lot sailing today to "tune" the mast according to Scott's book. I have a question concerning some blocks and clamcleats. I have the standard blocks attached to the stanchions with corresponding clamsleats for the jib sheets. But I also have a couple of blocks atop the cabin with camcleats that correspond to them...one per side. I originally thought this was for running the halyards to the cockpit but the blocks are a couple of feet away from the mast so the halyards would be running off from the mast and be in the way of the mainsail. Are they an alternative point for running jib sheets? If so, could someone tell me the advantage of having them in so close to center as opposed to the ones out at the stanchions? Just a little perplexed. THX