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Main sheet

T

terry_thatcher

Terence Thatcher
For many years I have used 1/2 inch Sta-Set polyester as my main sheet. I have a 6/1 block system. I want to replace the old sheet and want to get something smaller, maybe 7/16, that will run through the blocks easier and be lighter. I see no reason to spend money on ultra-low stretch rope like Dyneema for the main sheet; I don't race. But should I? I try to sail as fast as I can, even cruising. Do I need some give in the main sheet in case I fail to deploy my preventer and suffer an uncontrolled jibe? Comments and advice welcomed.
 
My main sheet is 12mm, and it is very draggy, I believe too large for the triple blocks and seems to have a lot of friction on itself. As I measure the blocks, they seem to be made for 3/8", so I bought some 3/8" polyester ( I recall, could be mistaken) and will try that. Seems like 100' will be enough. I have not been back to the boat yet to install it.
 
I don't see any reason for anything low stretch on the main sheet. Even racing. Someone might argue that in a gust, the stretch will ease the main slightly, which is what you would want anyway.
 
Terry

A couple of years ago I purchased 110 ft of Sta-Set which I ordered as 1/2". That whole summer I felt the line was not running through the Harken block system fast enough and was hanging up at times. I spoke to R&W ropes in MA, where I buy my line, and the person said that the line was sized in metric and that it was closer to 9/16". I then purchased the next smaller size metric line which was more like 7/16", which is perfect and runs through the blocks perfectly. The larger 9/16" line was then cut into two 55' lengths which are now the genoa sheets which are also perfect. I would see no reason to use the high modulars line on the sheets. On the halyards yes.

Jim
 
I guess we may have the same Harken 6/1 block. With that system, I think I can use 3/8" line, given the reduction in strain on each of the 6 lines. But what has always bothered me was the tiny 1/4" shackles. They seem much too small form the possible force. Our main, in 20 knots, would exert a force of 1000lb. In a jibe, it would be much more. Even my high test 1/4" shackles have only a 1650 SWL and a 3300 breaking load. I can't see drilling out the holes for a larger shackle, say 5/16", without weakening the attachment points on the blocks. Of course, I try to avoid jibes, but still that is less safety factor than I use on any other critical fitting. Comments?
 
Terry, I thought the exact same thing, the shackles seem too small, considering the overall load and strength of the blocks and lines. I had the lower shackle come loose last year and it scared the crap out of me.
 
I agree with you both. The attachment shackles are too small. BUT!!! We have been sailing "Dana" now coming up on 36 years, without any of the Harken main sheet rig failing. In that time frame there have been more accidental flying gybes then I am willing to admit. If those shackles could handle all that, then who am I to argue. Other then replacing them if they appear worn, I think I'll leave them.

Jim
 
I agree on the Sta-Set mainsheet. I'm in the process of replacing most of my running rigging too. Some with dyneema double braid, some lesser double braid. But the main sheet is 7/16" Sta-Set. I can't recall the length, about 100'. Mid boom sheet system.

I have a question, maybe for a seperate thread. Has anyone used double braid dyneema with the cover stripped back for their main halyard? I'd love to replace the wire to rope halyard that's nearly shot. Wondering about the masthead sheaves accepting the dyneema core.
Mitchell
 
DGA said:
Terry, I thought the exact same thing, the shackles seem too small, considering the overall load and strength of the blocks and lines. I had the lower shackle come loose last year and it scared the crap out of me.
Click to expand...
My lower attachment also gave way, but it was my fault. Shackle unthreaded. All are moused closed now with monel wire.
 
Mitchell: I believe if your sheave is for wire, you may want to replace it. Not hard to do, as long as you don't drop parts down the mast. Try Zephyrwerks in southwest Washington state. They make custom sheaves. Very reasonable.
 
Years ago we had an interesting dilemma. While sailing from Long Island Sound to Block Island, the wind gradually picked up as the day progressed. Started out on a stbd tack close reach in 10 to 12 kts. The winds were well over 20kts when we arrived. As the wind had increased, I had tightened the main halyard to keep the luff tight. When we entered the Great Salt Pond at Block we were motoring through the inlet with the main still up. I went forward to drop the main only to find that the sail refused to come down. That left us in a crowded anchorage in a strong wind and we couldn't get rid of the sail. Dana has climbing steps on the mast, so Bonnie kept the boat in the channel while I ran up the mast to investigate the problem. At the masthead I found that the topmost sail slide was cocked off the sail track, not allowing the sail to slide. A screwdriver solved the immediate problem and the sail came down. Disaster averted!

Later, talking to a very knowledgeable sailmaker, The cause of the incident was explained: As the wind had increased on the crossing, I had retightened the halyard tension to keep the luff tight. The halyard was probably Sta-Set X. The line stretched tight to do its job. When we entered the harbor, the wind speed fell with being in the shadow of the land. When that happened the line relaxed allowing the top sail slide to move up higher then the end of the track. His suggestion was to replace the halyards, both main and jib, with a high modular type of line. This was all before Dynemma came on the market. The line we brought is called T900. Big bucks but we never had that problem again.

Jim
 
A good and further endorsement for the Tides Strong Track. And maybe for using a cunningham tackle to adjust mainsail draft, rather than the halyard. Nonetheless, climbing the mast steps while the main is up reflects Jim's fearless seamanship.
 
Mitchell,
My boat came with rope halyards in '78.
I replaced the main with high tech line with the cover stripped. The smaller diameter came back to haunt me. A crew member let the halyard run free on a drop and the line jumped the sheave. It was a little hard to hoist and drop after that since it was running on the axle until the day it didn't come down.
One more time up the mast!
 
John that is a concern for me as well. I don't know what I have up there for sheaves. Need to investigate. I'm looking for less weight aloft and low stretch on the halyards. I replaced both wire to rope halyards and staset x on my Moore 24. Only about 29' off the deck. But the weight savings alone for 3 halyards was amazing.
 
Another recommendation for the the Tides Track. More of less no chance of a slide sticking. I can reef on any point of sail, no need to turn upwind or into irons. The mainsail will go up or down easily enough while still sailing, even downwind on a run. (though I need to be mindful of the sail getting caught in the shrouds as it comes down.)

Also, I highly recommend https://www.zephyrwerks.com/ for new sheaves. Cut to whatever rope size you want. You can change the main sheaves pretty easily with the mast up. For the jib sheave the forestay is in the way.
 
Back to main sheets: With a 6/1 purchase, the calculated main sheet load in a 20 knot wind is only 166 lbs per fall. Given that, 3/8" line would be fully adequate in terms of strength and stretch and, I think, handling. Is there any reason to get 7/16" rope? Does the group think 3/8" will be unhandy? It would sure be lighter, which helps in light airs--typical in Puget Sound.
 
In almost all cases, sheets are sized for feel in the hand. 1/4" would be strong enough with 6:1 purchase. I reduced mine from 6:1 to 5:1 because I was finding that I had too much line in the cockpit, and at times I couldn't pull it in quick enough during a jybe. It increased the load enough that I don't know if I would like line as small as 3/8" in my hand. But it might be ok with 6:1.
I don't wear gloves when I sail, even though it is generally recommended. If you usually do, then I am sure 3/8" would be fine.
 
I can't understand the reason for trying to get the smallest, most minimum, size lines for the running rigging. These are cruising boats, not racers. I'll take strength and comfort over speed.

Jim
 
terry_thatcher said:
For many years I have used 1/2 inch Sta-Set polyester as my main sheet. I have a 6/1 block system. I want to replace the old sheet and want to get something smaller, maybe 7/16, that will run through the blocks easier and be lighter. I see no reason to spend money on ultra-low stretch rope like Dyneema for the main sheet; I don't race. But should I? I try to sail as fast as I can, even cruising. Do I need some give in the main sheet in case I fail to deploy my preventer and suffer an uncontrolled jibe? Comments and advice welcomed.
Click to expand...
Hi Terry, A very good argument for NOT using hi-modulus line on mainsheets is to reduce shock load. Line with a bit of stretch is much better on the gear for mainsheets and main traveler controls. Check out New England Ropes Regatta Braid or Sampson Trophy Braid, both specifically designed for running rigging. Regatta is single braid, Trophy double braid. I might guess the Sampson Trophy braid in a 10 mm would both run better through blocks, and last longer for a cruising boat. And, note all lines are now built in metric with nominal imperial equivalents. This can make a difference when sizing line for rope clutches, blocks and shives, and self-tailing jaws.
Rand Hilo
 
Good to hear from you. I used to use regatta braid for sheets, but don't really like the "hand." I will look into the Trophy Braid.
Did you buy a boat?
 
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