Have you evaluated your exit block for the suitability of climbing the mast? In the factory setup, the axles are trapped in place by the welded-in sheave box. So even if a sheave failed, the axle would still hold the halyard in place. Just wondered if you've evaluated the failure modes for the exit block (that is, if you'll be using it to ascend the mast).
Ken, sorry for not responding sooner, I've been out of town sailing with 59 North from Ketchikan to Victoria followed by a trip through the San Juans to Victoria again aboard our boat to drop my wife off for her leg from Victoria to San Francisco!
Yes, I did consider the failure mode of this block, but not for climbing the mast. I was focused on the halyard load under sail. I think there are 2 basic failure modes for this block:
1. the axel or sheave breaks - if this happens and the block stays in the mast, the line will ride on the edged of the block which is contoured and does not have a sharp edge. It would not be fun if you're suspended by the line, but you should have no problem lowering a person or a loaded sail. In contrast, if this happened on the original sheave, the line would be riding on the sharp cut-out opening and could potentially cut the line.
2. the screws or rivets break and the block falls out of the mast -the block has a recessed shoulder that rests on the mast cut out, so the load isn't actually on the screws. Under load, the block should remain in place. If it doesn't, the line would ride on the mast cut out and could create a problem.
After spending some close personal time with both the original sheave box and these new exit blocks, I'm confident both are well designed and built. I have no problem hoisting a sail or climbing on either one.
to avoid my own personal therapy session like Bruce mentioned, my mast climbing setup includes an ascender, Grigri, and 150' dedicated climbing rope I rig each time I go up the mast. The rope is only used for this purpose and is kept in the cabin. When I rig it, I keep the extra 50' in the cockpit that I run through a clutch, around the halyard winch and self tailer, and secured to a cleat. If I did end up on the buisness end of the climbing rope with a broken block, I would still be able to lower myself. If the Grigri didn't work or I was unable to operate it, anyone on deck would be able to lower me using the cabin top winch and extra 50' of rope. It's a bit more work for the climber, but I prefer to be self sufficient and not have to rely on anyone on deck.
During the trip with 59 North, I got the opportunity to go up the rig of their Farr 65. They go the more standard route of using the primary winches to hoist a climber. With all 11 Crew on deck, massively oversized halyards and rigging, and secondary halyard, their system seemed safe as well.
On a different note, I finally figured out what happened to my wind instrument. The top cap was loose and allowed water to get into the circuit board compartment. It pooled at the bottom where the wind speed transducers are located. One of them is completely corroded which explains why I was still getting some reading, but it wasn't accurate. I ordered a new circuit board. Hopefully we'll have a working wind instrument soon.
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