Questions: Single Line Reefing - Looking for specifics and other questions

[Zephyros]

I'm putting together my Single Line Reefing design based on ideas from Bruce and Roger, a big thank you to both of them. Here is what I have so far, I will describe the layout fitting by fitting from clew reef to tack reef.

Starting at the port side aft end of the boom:
Line is anchored to a Pad Eye
Line routes up to a Ronstan Series 20mm Orbit Block RF25109 mounted at clew cringle via a soft shackle.
Line routes back down to a Ronstan 20mm RF20151A Cheek Block
Line routes forward along the boom to another Ronstan 20mm RF20151A Cheek Block
Line routes up to another Ronstan Series 20mm Orbit Block RF25109 mounted at tack cringle via a soft shackle.
Line routes back down to another Ronstan 20mm RF20151A Cheek Block mounted on the upper section of the mast hinge
Line continues down to a Ronstan 20mm Spring Block RF20141 which turns the line back to a deck top cleat of your choice, such as a Spinlock PXR

Notes:
This layout is for the Port side but it could just as well be done on the Starboard side. I chose the Port side as on my boat there is only the downhaul block and cleat on that side, where the starboard side has the two halyards. If you chose to do it on the starboard side you could reuse the current aft mounted clew reefing cheek block on the boom.
The Ronstan blocks were used for examples only, they could be changed to your favorite brand or style.
Specific details could be changed for your layout, such as the mast bast spring block could be one of numerous styles based on your layout.
The photo is the Sunday Cat factory brochure photo as it was the best flat view I could find. The design is intended to be generic for any Suncat, Suncat Daysailer or Sunday Cat.

All suggestions for improvements are welcome.

[bruce]

Looks good. I'm using 3/16" line with the Ronstan RF25109 block. That runs freely, but even though the block is rated for 6 mm, I'd test any 1/4" line you were considering to make sure it also ran well before investing. A soft, easily-handled 1/4" might be tight. The 1/4" Yale PhD Racer line I use on my CB pendant for example. Under load it's 1/4", but loose you'd swear it's 5/16".

[Roland of Macatawa]

Zephyros:

Are you sure that you want the cheekblock (or fairlead) on the upper half of the mast hinge, rather than below?
Think about how the line will 'package' for trailering when the boom, sail, and gaff are all below the mast hinge and the mast is folded down.

Otherwise, looks like a nice system.
Will be curious, when you have it assembled, how well it works.
Perhaps, I will copy it; after my current projects are completed.

Regards, Roland

[bruce]

It wouldn't hurt, but it won't be an issue. The reef line will be slack, the cringles will be down on the the boom because the sail is down, and the gooseneck will be below the hinge. The cheek block will pivot down and mostly aft maybe 4" when you drop the mast. The reef line will still be slack, now marginally more, but probably not so slack that it will get tangled because the slack will be distributed throughout the reefing line.

A cheek block is better, IMHO. As you set the reef, the angle to the turning point will get steeper, approaching 90 degrees if your turning point is mounted on the hinge. A fairlead is only efficient in shallow angles.

[Zephyros]

Are you sure that you want the cheekblock (or fairlead) on the upper half of the mast hinge, rather than below?
Think about how the line will 'package' for trailering when the boom, sail, and gaff are all below the mast hinge and the mast is folded down.

As you set the reef, the angle to the turning point will get steeper, approaching 90 degrees if your turning point is mounted on the hinge.

Great feedback, keep it coming. Here is the analysis for both mast raised and mast folded with the block at either the upper or lower mast hinge:

Pros & Cons:

Mast Raised:
Full Sail:  Line from Tack Reef Cringle routing down through either upper or lower mast hinge block is about equal.
Pros:  Reefed Sail:  Line from Tack Reef Cringle routing down to the lower mast hinge block allows a steeper angle when reefing which will help keep the luff tighter.

Mast Folded:
Pros:  Line routed through upper mast hinge block allows line to fold out and over, away from the hinge, with a straight drop down to the tack reef cringle.
Cons:  During mast raising, the upper mast hinge block will offer greater potential for the line to get pinched in the hinge.

Winner:  Block Mounted on Lower Mast Hinge

[Zephyros]

But in relooking at Tropical Boating:  Modifying my Sun Cat's Rigging
https://www.tropicalboating.com/2010/04/modifying-my-sun-cats-rigging

The simplicity of the single forward tack reef block with a boom mounted cleat in combination with the factory clew reef, this two line setup is not as convenient as I would like for single handed sailing, but it is tempting, decisions, decisions...



Also shown on page 45 of the manual, Modifying Sun Cat's Rigging
TomRay, Tropical Boating

Then, when all else fails, re-read the manual and re-visit:

Page 29, Single Line Reefing, Posted By: Jim B., Sun Cat
Our Sun Cat has a jam cleat and a horn cleat on the boom. The set-up is approximately: line attached at the front (tack) of the boom, up and through the grommet on the luff, back down to a turning block on the other side of the boom; line lead back to the aft end of the boom, another turning block, up through the grommet on the leach, back down to one more turning block, lead forward on the boom to the jam cleat and then secured with the horn cleat.

Page 40, Improving the Reefing System
My solution was to install an eye strap on the port side of the boom as far forward as possible, and a cheek block on the starboard side, also mounted as far forward as possible. A line goes from the eye strap through the cringle and down to the cheek block, then aft along the boom to another SeaDog Clamcleat mounted on the boom.

[bruce]

Tom,

I like your diagrams!

I suspect you're favoring mounting on the hinge because it provides a flat surface. Personally, I'd want to avoid the hinge because it's busy enough already on my boat. I lead the lines forward and around the long pin to keep them from getting tangled, works like a champ.

I'd mount the cheek block below the hinge, using a pad cut to the contour of the mast as necessary. Here's a photo of a block on my lazy jacks. That said, Com-Pac mounted the Harken 40mm Carbo cheek blocks at the base of my mast for the halyards without worrying about the curve in the mast surface. No problem, just not very finished.

Could you avoid the cheek block entirely, and run directly to your stand up block? Our, lower down, a fairlead might be all that is necessary. Just thinking out loud.

[Zephyros]

Bruce, great ideas. What is that block that is mounted on the wedge in the middle photo, a Harken 40mm Carbo? What about the wedge, is that a Harken accessory?

[bruce]

The block in the middle is a Selden BBB20, the Harken 40mm is at the bottom. Looks like the smallest plastic cheek block in the Harken Carbo line is the 29mm. So many choices. I like that there isn't SS on aluminum, except for the fasteners of course. I bed with butyl tape these days, wonderful stuff.
http://www.seldenmast.com/en/products/blocks/ball_bearing_blocks/bbb20/__item_402-101-13.html
https://www.harken.com/productdetail.aspx?id=4523&taxid=416

No, the wedge I made up out of Delrin. Might use black Starboard these days, possibly better UV resistance. We both store our boats indoors, so it isn't a big factor. They would be useful, but there's so many profiles out there, and where you mount on the profile would vary, it would be a hassle to stock them. Somebody like Dwyer could do it for their line, but they seem to favor SS backs that can be bent to conform.

I think I tried blowing up profile on the Dwyer site to life size, but it's just as fast to take an index card and fit it directly. Trimming a bit at a time, until you get a good match. Easy to cut on a bandsaw, do the back first while the work stands square on it's edge. Trimming the wedge to match the block footprint isn't as critical. Might be able to do it with a jig saw, though the blade does wander. A hand scroll or coping saw would be safer. Delrin and Starboard are very easy to work. Clean up with gouges, files, and finally sandpaper laid on top of the mast, so it is a sanding block.

You could bend a piece of SS bar stock, say 3/32", into a L shape with a couple of tabs for fasteners. Might need heat for the bends. Not as much fitting, but SS on the aluminum mast, and would be more apt to snag a line.

Same offer. It you want to go that way, but are challenged by the fabrication, I'll do it for cost.

[mikehennessy]

I tried using a ball stretch cord set for the mid-sail cringles.  Worked well on shore.  This is a modification (store purchased) of what Bruce did on his rig.  I'll just leave the cord set in the reef points and attach when the tack and luff are secured.

[mikehennessy]

Bruce:

What do you think of using a soft shackle to go through the tack reef point and around the hook supplied by Com-Pac as an improvement versus trying to put the cringle over the hook which can be difficult.

http://www.apsltd.com/fse-robline-dyneema-soft-shackle-4mm-5-32-gray.html

Regards,
Mike

[bruce]

I agree with you, Mike. First time I reefed I punched a hole in my sail with the hook. My bad. I've heard many add a loop to the cringle to grab.

The 5/32" soft shackle would work, but it's only 3.15" long. I think that's measured with the shackle stretched out, from the tip of the loop to the inside of the diamond knot, so circumference. That gives me a diameter of 1". Sounds tight. Best to check my numbers.

I'd take any small line and make a loop with a fisherman's knot to determine how big you want it. Actually, since you'll be leaving this in place, you could use Dyneema with a triple fisherman's knot, one of the few knots that is recommended for use with Dyneema. The knot will weaken the line significantly, but I'd go with at least 3/16" anyway for handling. If I were tying a soft shackle for this, where the line is buried in itself so the thickness is greatly increased, I'd use 1/8" or 5/32". The soft shackles test at almost full line strength. Quite amazing really.

You can also tie a loop with Dyneema, by burying the ends back into the line. But you need a minimum of 50 diameters of bury to hold well. For 1/8" line that's a bury of 6.25", two ends so double that, that's over 12" circumference. Too big, I would say.

[Zephyros]

I tried using a ball stretch cord set for the mid-sail cringles.  Worked well on shore.  This is a modification (store purchased) of what Bruce did on his rig.  I'll just leave the cord set in the reef points and attach when the tack and luff are secured.

Hi Mike,

Thanks for the suggestion, I'm going to give that a try.

[Zephyros]

Same offer. It you want to go that way, but are challenged by the fabrication, I'll do it for cost.

Bruce, thanks for the offer.

Could you avoid the cheek block entirely, and run directly to your stand up block? Our, lower down, a fairlead might be all that is necessary. Just thinking out loud.

Bruce, running with this suggestion with a slight twist, using a Swivel block cleat base, such as a Ronstan RF20175 or RF5.
https://www.ronstan.com/marine/product.asp?prodno=RF20175
https://www.ronstan.com/marine/product.asp?ProdNo=RF5

While the line angle from the tack reed cringle block may not be as far forward as desirable, it may be a good compromise. I found a few examples of this, such as:
http://barnaclebillholcomb.blogspot.com/2011/09/single-line-reefing-system.html?m=1

Below is an updated diagram with this approach, see diagram SC Single Line Reef Port 2 below.

I also made a diagram of the simpler original idea of everything contained on the boom using your RWO Lance cleat and a Racelite double cleat in diagram SC Single Line Reef Boom 1.

[bruce]

Tom,

I was never a fan for drawing the luff tighter to the mast, I'm not sure what the point is. Not reefed, the luff is parallel to the mast.

I know your boat isn't handy for testing, but I would try setting something up to see how you like it. You're set at the leech with the stock set up. Temporarily attach a turning point, e.g. a swivel block you have on hand, on the boom at the tack. Could be as simple as a C-clamp. Run the line up to the luff cringle, to another temporary block, or just through the cringle and back to the blocks and cleat you have in place for the boom downhaul. Temporarily tie a fixed downhaul at about the right height, and plan to tension the luff with the throat halyard. (I'm not familiar with the SC downhaul set up, but it sounds like it could be repurposed for a quick test.) Run a temporary single reefing line and see how it goes.

The lance cleat is nice in that it's simple and keeps the rig on the boom, but I doubt it will ever be as easy to use as a line run to a Spinlock cleat on the foredeck. Especially if there's significant force required to set the reef tight.

Follow up. I hadn't checked out your cleats. They look nice. Mounted on the mast sub, the load under shear. I wondered about that. On the PC, access to the deck is very poor. Where the halyard cleats are mounted on the coaming isn't backed, just self-tappers into a 1/4" of glass.