Dyneema single line reefing without clutch?

[Franziska]

Hi,



upfront we are in a budget, so simplicity and low cost are favoured. Less weight, even better.

Boat is a 35ft cruising cat with full batten sail and lazy bag. Mainsail is fairly small with about 30m2.



Our 10mm reefing lines terminate currently in clutches along the boom, which necessitates climbing onto the cabin and reffing from the mast step. Not good in a storm.



So, I thought about what would be the cheapest solution to change this and lean towards oversized low friction rings with 6-8mm dyneema core material such as Dyna One.

Raw Dyneema because it's ensuring even less friction in the low friction rings.



Clearly the current clutches do not hold 6mm raw Dyneema, for one because it's to thin for our current clutches and because it's to slippery.



So, I thought about making loop splices within the reef lines at the line position where the would normally enter a clutch on deck when reefed.

These loops would slide through the oversized low friction rings at the mast foot.

Instead of deck clutches I'd bolt through a small low friction ring vertically.


So to reef, pull up the topping lift, open the halyard, pull in the single Dyneema reefing line and at the end slide the loop over the vertical Dyneema ring.

Then, pull the main halyard in with the winch to put tension back on the main.



This would safe us from buying expensive new clutches and a bunch of expensive blocks. Added benefit it would be lightweight and low cost.



Thoughts?
Will we get away with putting tension back on the mainsail by pulling only on the main halyard?

Did anyone else terminate Dyneema lines with a loop which slide over a simple vertical stud on deck?

[MJF]

Hi Franziska,

You could buy a cover and slide it over your 6 or 8mm dyneema core reefing line and fix it in place where your reefing line will sit in the clutch. Make it overlap at the front and back a length.
This gives you the grip you need and you can repurpose your old clutches.
To increase holding power in the clutch, you could also put a “filler” inside the reefing line to bulk up the line even more. A filler would be a thin 1 or 2mm dyneema line that you put inside the core of your reefing line and the desired spot.

[Franziska]

Originally Posted by MJF

Hi Franziska,

You could buy a cover and slide it over your 6 or 8mm dyneema core reefing line and fix it in place where your reefing line will sit in the clutch. Make it overlap at the front and back a length.
This gives you the grip you need and you can repurpose your old clutches.
To increase holding power in the clutch, you could also put a “filler” inside the reefing line to bulk up the line even more. A filler would be a thin 1 or 2mm dyneema line that you put inside the core of your reefing line and the desired spot.

Thanks, thought about that, but that would mean the stiffer part needs to run through the low friction eyes, which I would like to avoid.



Probably I'll just have to give it a shot to see how well the proposed system works and then report back...

[Jammer]

The usual solution is to splice a piece of cover over the portion of the line that will be held by the clutch, often continuing from there to the bitter end so that the portion being wrapped around the winch also has cover.

[fxykty]

Friction is the enemy when using single line reefing; using smaller diameter bare Dyneema is a good start, but not sufficient. A single line system needs to tension both clew and tack and the tension throughout the reefing line needs to be equalised. You will have 2x 180* turns and 3x 90* turns. To equalise the tension you need very low friction - and low friction rings (LFR) on the 180* turns won’t work. You need good ball bearing blocks there (since your main is relatively small, otherwise roller bearing blocks are needed). For the 90* turns, maybe LFR will work, but probably safer to use ball bearing blocks there as well.

Remember that LFR are good when you have low load and high movement, or high load and low movement. Single line reefing is high load and high movement - a use case that calls for blocks.

[Jesse Preston]

I wouldn't worry about using the cover causing too much extra friction, especially if you tapered it so the cover just started where the clutch needed it. The system would be under its highest load when you are nearing the end of putting the reef in, by which point the cover would be through all the rings. I would worry about a loop getting hung up in the rings and causing you more problems then a bit of friction from a cover.

I would also consider putting a friction ring on the tack and clew as the standard cringles in sails are not shaped for low friction, something like this,
https://www.cruisingsolutions.com/pr...-nodus-factory

[Franziska]

Originally Posted by Jesse Preston

I wouldn't worry about using the cover causing too much extra friction, especially if you tapered it so the cover just started where the clutch needed it. The system would be under its highest load when you are nearing the end of putting the reef in, by which point the cover would be through all the rings. I would worry about a loop getting hung up in the rings and causing you more problems then a bit of friction from a cover.

I would also consider putting a friction ring on the tack and clew as the standard cringles in sails are not shaped for low friction, something like this,
https://www.cruisingsolutions.com/pr...-nodus-factory

For the reefing cringles I'm looking into these:

https://www.rutgerson.se/product/quick-reef-solution/


Clever solution.

[donradcliffe]

The only single line reefing system that I have seen work well was a Jeanneau that had blocks on the reefing tacks and clews of the sails, as well as blocks in the boom. Otherwise its too much friction. You also have to handle a lot of line, especially for the second reef.

[thinwater]

Originally Posted by Franziska

Thanks, thought about that, but that would mean the stiffer part needs to run through the low friction eyes, which I would like to avoid.

Probably I'll just have to give it a shot to see how well the proposed system works and then report back...

I have done this (covered Amsteel).



Yes, the friction is greater where the polyester cover is, but toward the end, when tensioning the reef, There is only Dyneema over the rings. It's a compromise for simplicity.



Covering Dyneema is very easy. The cheapest source of cover is typically Samson XL. That said, you may have good sections of cover on old lines that you can use. For example, the parts of halyards that live inside the mast don't really age, and the strength comes from the Dyneema core anyway.

[thinwater]

Originally Posted by Franziska

For the reefing cringles I'm looking into these:

https://www.rutgerson.se/product/quick-reef-solution/


Clever solution.

Clever, but stupid price.



For the clews it is simple to attach rings with webbing. In fact, North Sails attaches rings with webbing for the tacks as well.


Notice also that they positioned it so that the line pulls forward as well as down, the balance the outhaul tension and keep the luff in line.

[Tupaia]

Why not convert to twin line reefing, a line for the leach and a line for the luff. Much simpler much less friction and nothing to get fouled up. Nearly all of the hardware is already there. If you fit horns and strops you don't even need clutches for the luff.

[Franziska]

Originally Posted by Tupaia

Why not convert to twin line reefing, a line for the leach and a line for the luff. Much simpler much less friction and nothing to get fouled up. Nearly all of the hardware is already there. If you fit horns and strops you don't even need clutches for the luff.

The point of the exercise is not to have to climb onto the roof and to the mastfoot anymore in bad weather.

Currently that's what we need to do.



As I'm the sailoress in our case the desaster would be fairly big if I go overboard.

It's just unsafe, despite harness, lifewest and being a cat and not wheeling over much.



With two point reefing I would still need todo that, or, I have more lines arriving at the cockpit.

[Tupaia]

Originally Posted by Franziska

The point of the exercise is not to have to climb onto the roof and to the mastfoot anymore in bad weather.

Currently that's what we need to do.



As I'm the sailoress in our case the desaster would be fairly big if I go overboard.

It's just unsafe, despite harness, lifewest and being a cat and not wheeling over much.



With two point reefing I would still need todo that, or, I have more lines arriving at the cockpit.

So are you looking to bring the lines back to the cockpit?


If so the already heavy friction load on single line reefing makes this more difficult. You could bring twin line reefing back to the cockpit relatively easily, using a double foot-block at the base of the mast for each reef.


Obviously the main halyard also needs to get to the cockpit.

[barnakiel]

If you have a problem finding a clutch solution you can always cleat the line rather than clutch it.


We sometimes get so embroiled with the new that we look past the old.


b.

[Franziska]

Originally Posted by barnakiel

If you have a problem finding a clutch solution you can always cleat the line rather than clutch it.


We sometimes get so embroiled with the new that we look past the old.


b.

Thanks. I have a different plan for that.
Dyneema core does not like to be clamped, it tends to slip.



So I will try with loops spliced in at the location in the reef line which would be normally clamped.
These loops are hooked over a kind of peg.
Then everything gets tightened by pulling the mainhalyard tight again.

Will see how this works.