by talbot » Thu Jun 06, 2013 6:15 pm
I just put a small cheek block on the starboard side of the mast. My windex is installed on the other side. The screw or rivet length is not a problem, because fastenerscan protrude into the body of the mast. The working end of the line fastens to whatever fitting you have on the end of the boom, and the bitter end belays somewhere around the base of the mast. A couple of other things I learned:
* 4mm line, particularly with a Spectra or Dyneema core, is amply strong. However, it's a little small for handling and cleating. If you want to reduce weight aloft, you could put a small line through the cheekblock and tie it to a larger line forward of the block that runs down to your cleat. Dropping the boom on a crew/family member because the line slips out of a cleat or your fingers has repercussions that can last for years. I know this for a fact.
* Putting a topping-lift sparcleat low on the forward surface of the mast seems to snag the jib sheets on every tack. Putting the cleat low on the starboard side of the mast in line with the cheek block only snags the jib sheets on 50% of your tacks. To stay clear of other running rigging, locate the topping lift cleat high, at about the same level as a whisker pole or spinnaker ring. In fact, if you've got a whisker pole ring on the mast already, just tie the TL off there with half hitches. (You can also run the lift halyard down to the base of the mast and aft to the cockpit, but that involves some tedious tinkering with blocks and cleats.)
* Once your topping lift is in place, remember that your boom is a 10' lever with huge mechanical advantage. I once broke a vang shackle that I forget to unfasten before hauling on the topping left to tension a boom tent. If you have center-boom sheeting, you can bend the boom by pulling hard on the TL with the main sheet cleated. On the other hand, the TL makes it simple to adjust shroud tension. With the main sheet cleated, a moderate tug on the TL will slacken the shrouds enough to turn the adjusters easily by hand.