GreenLake wrote:Until I hear something convincing or until I can run a comparison, my thingking would be to ignore the friction in the loaded case.
GreenLake,
Okay, I decided to try some rope tricks. I put couple of 5 pound weights in the bucket and hung it from my old 5:1 Lewmar vang. It's set up as two fiddle blocks with 40 mm and 25 mm sheaves. It's got 3/8 inch double braided which I'm pretty sure is original. The line does not touch the cheeks. There is a noticeable amount of friction in this set up. The sheaves are not ball bearing so obviously there's friction there. It is obvious in playing out the line that there is a fair amount of drag.
Next, I hung the 10 pound bucket from two new Harken Carbo blocks in a 3:1 set up, one of them 40 mm the other one 75 mm. I also used 3/8 line. Interestingly, the 3:1 set up is almost as easy to haul in as the 5:1. I flipped over the Lewmar to make it 4:1 with two 25 mm and one 40 mm. In this set up the effort to haul in the load was pretty close but was more difficult with the Lewmar. Now, with the Harken blocks freewheeling the effort to hold the weight up was definitely less with the friction in the Lewmar, especially at 5:1. Switching on either one of the ratchets on the Harken's makes them easier to hold even at 3:1 with both set the weight of the line was just about enough to hold the 10 pound bucket.
Then, I grabbed a cheap old Ronstan 3:1 vang, this was set up with 3/8 line as well and was pretty much stuffed into the blocks. It drags on the cheeks. The friction in that one is overwhelming.
So, I believe that sizing the line and blocks correctly, not to mention using quality blocks, does make a huge difference in the friction.
KC