Main sheet rigging

Moderator: GreenLake

Main sheet rigging

Postby oian » Sun Jun 26, 2016 3:23 pm

I just purchased a well taken care of 1978 DS2 and have a question on main sheet rigging. I was told that the rigging was for mid-boom, but there are small blocks on either side of the transom and a small attachment on the end of the boom. It appears that this was for a prior stern sheeting arrangement. Any suggestions as to the prior arrangement. A diagram would be very helpful.
Thanks, John
oian
 
Posts: 9
Joined: Sun Jun 19, 2016 12:23 am

Re: Main sheet rigging

Postby GreenLake » Sun Jun 26, 2016 5:31 pm

There are various ways you could rig this
1318
99
100
The setup here shows a 2:1 purchase between boom and traveler (triangle).

The block at the apex of the triangle is knotted to the traveler.

There are several ways to adjust the traveler. A cheap one is to tie the two ends together so that the traveler is a fixed triangle. Make sure the knot has a loop - that loop can be hooked over a hook, perhaps under the coaming, to "center" the traveler. When released, the knot can travel between the two blocks on the transom, allowing the apex to swing off-center for downwind runs (requiring less mainsheet).

You could run both tails through a dual sheet block on the deck, and lead them forward. Then knot or splice them together about a foot from the cheek block and provide some cleat for the remaining single tail. That way, you can adjust the height of the triangle, while keeping it always centered.

There are many other interesting sheeting arrangements that you can use those transom blocks for. For example, you can simply run the main to a block at the end of the boom, then through both blocks on the transom, then back up to the end of the boom (and attach there). This gives you a similar arrangement, but without a way to arrest or adjust the traveler. That's how my boat used to be set up when I got it.

Mine is now rigged like in the top picture. I was following the rigging guide by Phill Root http://forum.daysailer.org/tech_rigguide.phpwho also supplied the bottom pictures, but they seem to show the variant with cheek block on deck, not the fixed triangle traveler with hook under the coaming shown in his guide.
~ green ~ lake ~ ~
GreenLake
 
Posts: 7135
Joined: Mon Jun 18, 2007 3:54 am

Re: Main sheet rigging

Postby DigitalMechanic » Mon Jun 27, 2016 9:48 am

I just went though re-rigging my boat which is a 1976 DSII. There is a thread here about what I did to my boat on the subjects of mainsheet rigging, jib sheet rigging, and boom vang, through collaboration with other folks on this board. It is located here...

http://forum.daysailer.org/forum/viewtopic.php?f=12&t=5110

It is only 11 pages long lol, so I will point you to the page that has some pictures of my mainsheet setup for reference...

http://forum.daysailer.org/forum/viewtopic.php?f=12&t=5110&start=60

If you decide to try the mid-boom sheeting, this should help you get an idea of how the mid-boom sheeting can be setup, most likely using what you have now. If you are looking to do a modification, I am very very very pleased with my main sheet mod. It makes the boat sooooooooo much more fun to sail (vs the original upside down cleating of the sheet on the centerboard trunk). I used a fiddle block on a swivel cam (facing up) at the centerboard trunk and a ratchet block on the boom. This allows me to hike out and easily lift the mainsheet when I want to make adjustments to the mainsail, then I just pull down to make them stick of I need to free that hand back up for something else (like a beer can ;) )
DigitalMechanic
 
Posts: 374
Joined: Sat Nov 07, 2015 7:00 am
Location: Jacksonville, FL

Re: Main sheet rigging

Postby kokko » Thu Jun 30, 2016 10:32 am

Mid-boom sheeting halves your purchase power. Think of the boom as a lever. End boom gives you a level that is twice as long. Currently you have a single with a becket at the end of the boom and a single on the traveler.
Put a double block at the end of the boom, and a single with a becket at your traveler and you will have 3:1 instead of 2:1.
If you put a double block end boom and a double with a becket at the traveler, then you would have 4:1 purchase.

Every block you add increases the friction so there are diminishing returns. a theoretical 8:1 using a combination of mid and end boom sheeting is not much better than a 6:1. It requires a longer mainsheet and the line does not run as freely due to all the friction.

I wish I had a way of sending you a drawing, but I do not. I have found it easy to draw circles for blocks and trace the path of the mainsheet.
DS1 Truelove
kokko
 
Posts: 469
Joined: Tue Mar 11, 2008 4:17 pm
Location: St. Paul, MN

Re: Main sheet rigging

Postby kokko » Thu Jun 30, 2016 10:43 am

btw. The blocks port and starboard at the stern are for a Crosby rig which forms a triangle from a block at the end of the boom to the block on one side, across the transom to the block on the other side, and back up to the boom. It has a theoretical purchase power of about the square root of 2, or about 1.4.
I found it clutters the transom and catches my engine. I scrapped the Crosby rig, and set up a bridle more inboard with two padeyes. My bridle forms a triangle of about 16" on each side to which I have connect a double at the bridle and a double with becket at the end boom, for 4:1. The double with becket should be a fiddle with becket, but I have not purchased it yet.
DS1 Truelove
kokko
 
Posts: 469
Joined: Tue Mar 11, 2008 4:17 pm
Location: St. Paul, MN

Re: Main sheet rigging

Postby SUNBIRD » Fri Jul 01, 2016 1:51 pm

A 1978 Day Sailer would have come from the factory with mid-boom sheeting. However, there are some advantages as stated to the older end-boom setup. Disadvantages are need for longer mainsheet and all that rigging aft.

Anyway, here I the diagram from the Expanded DS II owners Manual that I created, it shows variations on the Crosby and other end-boom setups.
Attachments
Main-Jib sheets2.jpg
Early DS rigging Main sheet
Main-Jib sheets2.jpg (122.07 KiB) Viewed 7043 times
Rod Johnson, "SUNBIRD"
1979 DS II, # 10201
SUNBIRD
 
Posts: 100
Joined: Tue Oct 19, 2004 6:05 pm
Location: Massachusetts

Re: Main sheet rigging

Postby MookaCB » Fri Jul 01, 2016 2:49 pm

I use mid-boom sheeting with 4 parts, sometimes 4 parts do not seem like enough, but my ratchet block helps. I definitely miss having a traveler like on the larger keel boats I have sailed. Last week we were in heavy winds, and being able to adjust a traveler would have helped me point.

Should I try to set up boom end sheeting so I can incorporate the traveler to help point?
MookaCB
 
Posts: 36
Joined: Sat Jul 04, 2015 12:42 am

Re: Main sheet rigging

Postby SUNBIRD » Tue Jul 05, 2016 7:16 pm

Gee, I have a 3-part mainsheet mid-boom..... yes, it is hard to trim the sail at times, but the way my lower block and camcleat are set up, I can get extra "mechanical" advantage using my foot...... holding the tail of the sheet in one hand, I push down on the sheet with my foot and it is amazing how much further in I can get the sheet that way.

Some owners (especially racers) have added a traveler across the cockpit for the mid-boom sheeting. I would think that the track would be a tripping hazard, but it would give you all those "big-boat" tweeks with the traveler to play with.
A rope traveler across the stern with end-boom sheeting is also popular with racers. My diagrams (sketches?) show some options for those setups.
Rod Johnson, "SUNBIRD"
1979 DS II, # 10201
SUNBIRD
 
Posts: 100
Joined: Tue Oct 19, 2004 6:05 pm
Location: Massachusetts

Re: Main sheet rigging

Postby curifin » Sun Jul 10, 2016 8:24 pm

I kept the mid boom even though there are a lot of advantages to end boom split tail as described by the go fast folks here. Mid boom frees up the end of the boat for comings and going of kids and dogs and wives. It will bend the boom though so there is that, and you need to mind the vang on a reach but really with the swept spreaders on the DS it is not a really big deal. I have 4 to 1 block and never really had a problem with power on sheeting but... it will wear you out on a windy day when you NEVER want to cleat the sheet.
1970 DS1 "Denial"
1993 Beneteau First 210 "Dory"
curifin
 
Posts: 63
Joined: Tue Feb 19, 2013 10:49 pm


Return to Rigging

Who is online

Users browsing this forum: No registered users and 13 guests

cron