End Boom main sheet setup Purchase and Line

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End Boom main sheet setup Purchase and Line

Postby bluesman » Sun Jul 27, 2014 9:18 am

What is the standard diameter for the main sheet?

What is a typical mechanical advantage that is used?

Thanks
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Re: standard main sheet setup

Postby GreenLake » Sun Jul 27, 2014 4:18 pm

I think I am using 3/8".

The diameter is really given by what you can hold, because modern ropes are ample strong even at smaller diameters.

I replaced one of the blocks for the main with this ratchet block (the one shown here is installed for the jib, but I use the same kind of block for the main).

1818

I would not recommend the same kind of line as shown - it's too bulky, too heavy and to slippery (but it was free, and the perfect length when I needed a new jib sheet).

For my main I use FSE Robline's "racing sheet" which is smooth-running as well as grippy.

By using a ratchet block, I need to rely less on the mechanical advantage of the purchase if I want to hold the sheet in my hand (and not cleat it). My setup has 2.5:1 mechanical advantage (as measured at the end of the boom) which is equivalent to 5:1 for a pure center-boom setup. A 4:1 center-boom setup would also be typical, and many people have that. (My mainsheet setup is about the same as described here: http://forum.daysailer.org/tech_rigguide.php).
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Re: standard main sheet setup

Postby bluesman » Mon Jul 28, 2014 10:32 am

So Greenlake are you running the main with a block on the traveler, and fiddle block on the end of the boom?? Are you running 8mm line on your main?

I am going to replace my mainsheet and I would greatly prefer something heavier like3/8" line since my hands don't like gripping thinner lines.

I am thinking of buying a block and fiddle block to handle the purchase at the end of boom, and adding a ratcheting block mid boom. Thoughts?
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End Boom Main sheet Rigging purchase and line size

Postby bluesman » Mon Jul 28, 2014 11:14 am

Needing to redo my mainsheet on my 17' DS1 style daysailer I am wondering if a simple 2:1 using a single block on the traveler and a becket block on the boom is all I need and If I can use 3/8" line. My hands prefer thicker line but I want the main to be sensitive and responsive.

I believe this is pretty much the stock setup on the DS1?

Is a simple 2:1 setup fine and can I get away with 3/8 or should I really use 5/16 is is recommended for end boom application?

I am planning on using a ratcheting block so that I am thinking 2:1 could be OK, not sure if I need 3:1 at end of boom?

Also wondering what mainsheet line make and model folks are using?
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Re: End Boom Main sheet Rigging purchase and line size

Postby jeadstx » Mon Jul 28, 2014 1:51 pm

I use 3/8" line for the mainsheet on my DSII. I have mid-boom sheeting. As I recall, the end boom sheeting spec calls for about 45' of line, whereas the mid-boom sheet is 35' to 38', can't remeber how much I used.

John
1976 Day Sailer II, #8075 - Completed the 2011, 2012, and 2013 Texas 200
1952 Beetle Boat Swan Catboat
Early Rhodes 19
1973 Mariner 2+2, #2607 - Completed 2014, 2015 and 2016 Texas 200
1969 Day Sailer I, #3229
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Re: standard main sheet setup

Postby GreenLake » Mon Jul 28, 2014 11:39 pm

3/8" is 9.5 mm and the line that I use is listed at 9mm - after having used a much more massive main sheet that came with the boat. The use of the ratchet block reduces the force required to hold the main.

I think the type of line matters a bit as well. A line that's not slippery is easier to hold onto. I'm happy with the racing sheet from FSE Robline in that regard - my current jib sheet, which is a tad bulkier is also much more slippery and I would not dream of substituting it. In other words, even though my main sheet is a fraction of a mm under 3/8", I don't think that matters in the overall usability.

The ratchet block I use accepts 10mm, so will be fine with any line that's nominally 3/8" whether its a fraction of a mm thinner as my main or a fraction thicker as my jib sheet.

I do use a block on the traveler and a block with a becket on the end of the boom (there are 2 parts of the sheet between boom and traveler, as shown in the rigging guide). Using a fiddle block would allow you to double the purchase at the end of the boom to 4 parts, but then you would have double the main sheet tail in the cockpit (and nearly double the overall length - not worth it in my view, and not needed).
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Re: End Boom Main sheet Rigging purchase and line size

Postby GreenLake » Tue Jul 29, 2014 12:07 am

I found that there were two threads in different sections of the forum asking nearly the same question. I've used the "merge" facility to combine them in one location, but the result isn't as pretty as I'd like. The merged posts each have a different subject line based on the original thread so you can tell which came from where - except the first post where I made a new merged subject line.
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Re: End Boom main sheet setup Purchase and Line

Postby bluesman » Tue Jul 29, 2014 11:13 am

Thank you for the guidance.

I have purchased a Harken Carbo 57mm block that will go mid boom or on replace the block on the swivel cam cleat (depending if it fits)

I also purchased a 40 MM carbo block to attach to the traveler, and a 40mm carbo block with Becket to go on the boom

I will use my existing 3/8 line and if I find it too heavy I will replace with some thinner 5/16 (8mm) mainsheet.

I will let you know how this works on my boat.
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Re: End Boom main sheet setup Purchase and Line

Postby GreenLake » Tue Jul 29, 2014 12:18 pm

For the 57mm, did you get the plain single block or the Ratchamatic? You wrote earlier that you were going to get the ratcheting one. If you did, that will make the biggest difference. I looked up the specs for the ratcheting version of the block and it looks very similar to the one I have.
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Re: End Boom main sheet setup Purchase and Line

Postby bluesman » Wed Jul 30, 2014 12:54 pm

Upon the advice of the seller, Sounds Boatworks I got the manual switched Ratcheting Harken block
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Re: End Boom main sheet setup Purchase and Line

Postby GreenLake » Wed Jul 30, 2014 6:13 pm

I have an older Harken manual ratchet on another boat. The controls to engage the ratchet are large and easy to use. If yours are similar it should work well.

The ratchets on my DS have three settings, on, off, and auto. The controls are fiddly, so once I managed to get the things set to auto, I've left them there. Never felt that they engaged when they shouldn't or vice versa. What makes an autoratchet especially useful is that much of my sailing is in the evening in dying or variable winds. This way, I don't have to remember to switch settings.
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Re: End Boom main sheet setup Purchase and Line

Postby K.C. Walker » Fri Aug 01, 2014 9:54 pm

I'm joining this thread late because I've been out of town, off the grid, and sailing my DaySailer. I use 8mm Bzz line from New England Ropes. I like it. It runs really well through the blocks, is super flexible and single braid, so doesn't tangle much. It feels really nice in hand, soft and grippy. Oh yes, and it's reasonably priced.

A 2:1 purchase at the end of the boom in my opinion is plenty. I've used 1:1 at the end of the boom for a lot of the summer and that seems fine, also. I do use sailing gloves most of the time now. I have a Harken 75 mm manual ratchet block on the swivel cleat, on the centerboard trunk. With either 1:1 or 2:1 I mostly leave it engaged. I'm sure the 57 mm Harken will work great, I got mine at a really good price, otherwise I would have gone with a 57. When I've been using the 1:1 I do find I'm using my additional 40 mm ratchet block on the boom when the wind gets up. With the 2:1 I pretty much never engaged the 40 mm on the boom.

I had been using 2:1 for a long time and then Mike Gillum said that he was using a 1:1 with a split tail for his mainsheet. I decided to try at least the 1:1 part, and surprisingly, I found that it works pretty well. It definitely feels more responsive.

I think using quality blocks and line reduces the friction enough that going down to 8 mm still feels comfortable.
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Re: End Boom main sheet setup Purchase and Line

Postby GreenLake » Sat Aug 02, 2014 12:17 am

The British magazine, Practical Boat Owner happened to run a test of ratchet blocks in their latest issue.

It turns out that they found two significant differences between the Ronstan Orbit blocks and the rest (including Harken Carbo 57).

One difference is in the holding power. They essentially measured double the holding power for the Ronstan Orbit blocks.

The other difference is in chafe. They noticed that the additional holding power comes at a cost, which is that there is observable chafe on the line.

I must admit that I do observe chafe on my mainsheet, but, because the rope has a surface that looks, if anything, like a rag wool sock, I had thought that a bit of fuzziness was part of the design. That said, I've put several seasons on the main sheet and ratchet block, and it will be quite a few more seasons before I need to worry about switching the sheet end-for-end because of chafe. In the meantime, I enjoy the superior holding power, and translating that to K.C.'s experience, I'll expect that I'll never need a second ratchet block for the mainsheet...
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Re: End Boom main sheet setup Purchase and Line

Postby Mike Gillum » Sat Aug 09, 2014 12:34 am

On the boom I'm using a 57mm Carbo Ratchamatic as it'll ratchet under load and freewheel the rest of the time.
The base is the older small Harken Hexaratchet with the flip slip as I'll flip off the ratchet off wind.
My new split-tail mainsheet is a cheap 5/16" polyester cover over the 1/8" Spectra tails and it works quite well.
I didn't start wearing gloves until about five years ago when I started racing Lasers again after a 30 year hiatus.
I found fewer scrapes that some how appear out of thin air and less blood in the boat wearing gloves.
Mike Gillum DS #2772 BUBBA
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