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Single Line Reefing

jviss

.
Feb 5, 2004
4,627
Tartan 3800 Westport, MA
I learned today, quite by accident, that the single line reefing system on the Tartan 3800, with spar and boom supplied by Offshore Spars, is actually the Isomat AutoReef System. Rig-Rite, in Rhode Island, lists the system parts; not sure what is still available.

Mine is not rigged properly. When we picked up the boat, reef one was not tied to the boom at the boom outboard end, and reef two was absent.

I'm hoping the "shuttle blocks" for both reefs are still inside the boom. I can't imagine they aren't, but I can! :) If so, I will fish the reef one shuttle blow and reeve messengers. I'm not happy with the reef one line, and maybe will re-do that.

Can anyone comment on type and size of lines for single line reefing on a 38' boat? I assume Sta-Set or equivalent, "low-tech," double-braid is sufficient. Input welcome and appreciated.

Thanks,

jv
 
Jan 1, 2006
5,994
Slickcraft 26 Greenport, NY
I would go the other way. Smaller high tech line. It will go thru blocks more easily and won't stretch. Stretching is why your well tied reef gets sloppy and doesn't work well. I would consider something like Salsa. 1/4" or 5/16ths would probably do. The 5/16ths has a tensile strength of 3650. Way enough.
 

jviss

.
Feb 5, 2004
4,627
Tartan 3800 Westport, MA
Interesting, I did't think stretch in a reef line is that critical. I also want something that's good in the hands, in the rope clutches, and perhaps even on the winch. Some of the small lines are great from a stretch and strength perspective, but too small for the hand and winches.
 
Dec 18, 2012
138
Hunter 37.5 Annapolis
We have the isomat single line reefing on our Hunter 37.5. The lines are 7/16" standard double braid. I haven't had problems with line stretching, but I do crank the reef line very tight. I do have problems with friction, but that is partially due to the age of the lines.

Paul
 

jviss

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Feb 5, 2004
4,627
Tartan 3800 Westport, MA
Thanks Paul. I would think that with all of that mechanical advantage one could go down to 3/8" or even 8mm line.
 

jviss

.
Feb 5, 2004
4,627
Tartan 3800 Westport, MA
UPDATED, CORRECTED:

So, after another weekend on the boat, I can say that I don't have the Isomat AutoReef system, as illustrated in the two images, below. At least, I don't think I do.

I do, indeed, have two sheaves facing up at the outboard end of the boom (actually three, since there's one for the outhaul), and four facing down at the gooseneck; but I don't have the outboard endplate with the holes for the stopper knots, and there are no shuttle blocks present.

There actually is a small end plate with three holes in it. The holes are 3/8"

There is a ring at the top of the vang bracket to which I can attach a double block.

In addition, there are turning blocks attached to the mast collar, and one fairlead on each side of the mast, as in these drawings.

Any input on how to rig this?

Thanks,

jv
 
Last edited:

jviss

.
Feb 5, 2004
4,627
Tartan 3800 Westport, MA
It occurs to me there may be other places to fix the clew lines besides holes in an end plate, I will have to examine the boom more closely. If so, maybe I just need shuttle blocks and a double block.
 
Oct 26, 2008
4,994
Catalina 320 Barnegat, NJ
I would consider Sampson Warpspeed for these control lines. I use it for halyards and find that it is pretty stiff and not very easy on the hands, but excellent running through the sheaves and holding in the clutches or cleats. I have 8 mm for the halyards for light weight and less friction through the sheaves at the top of the mast. This is what I will use for my reefing lines when I change them out, but on your boat I would probably use 3/8" (9.5 mm). You want low stretch, less friction, so I agree with Andrew, except that I would probably increase the diameter for handling and I think 1/4" is just not enough. I can burn my hand pretty easily on this stuff with 8 mm ... I can imaging how bad it would be with 6 mm. The Salsa might be a lot easier on the hands I think. For control lines that are not frequently handled (like sheets) I don't consider the comfort of the line as being most important quality.
 
Sep 25, 2008
923
Macgregor & Island Packet VENTURE 25 & IP-38 NORTH EAST, MD
My two cents here. I would use New England Ropes VPC in 3/8" for your reefing lines. It will go through the many blocks/sheaves with ease and is plenty strong. You could probably go down to 5/16, but it'd be harder on your hands. Oh, and it's very cost effective. Salsa line is a great choice for sheets, but little else.
 

jviss

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Feb 5, 2004
4,627
Tartan 3800 Westport, MA
My two cents here. I would use New England Ropes VPC in 3/8" for your reefing lines. It will go through the many blocks/sheaves with ease and is plenty strong. You could probably go down to 5/16, but it'd be harder on your hands. Oh, and it's very cost effective. Salsa line is a great choice for sheets, but little else.
Thanks. I like VPC, put it on my C36 for halyards last year. It only comes in metric sizes, 6, 8, 10, 11, 12mm. Their catalog equates 3/8" with 10mm, and 5/16" with 8mm, but 3/8" is really 9.5mm, while 5/16" really is is 8mm. That's what I was thinking of using. The only issue is that I've found I had to sew the cover to the core before whipping. I have done eye splices in all kinds of line, but I prefer a hitch or knot now, as it makes end-for-ending easier. I might finish these with a Flemish eye for ease of pulling in/out for winter haul-out, leaving messengers in place in the boom. For the C36 halyard I used a seized halyard hitch onto the shackle.
 

jviss

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Feb 5, 2004
4,627
Tartan 3800 Westport, MA
But now, back to the O.P.'s question of the moment - how to rig the reefing lines???
 
Oct 26, 2008
4,994
Catalina 320 Barnegat, NJ
Interesting, the sheets are the most often handled lines on our boat; and, I thought, most boats.
Yep, I meant that opposed to lines that are handled frequently (like sheets). I must have had a brain warp. :confused:
 
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jviss

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Feb 5, 2004
4,627
Tartan 3800 Westport, MA
Since I haven't found them on-board, and I want to try this, I just ordered a couple of these. I got a good price, as it was the last pair in stock at one supplier, and he was clearing them out. Only downside, they are in the UK.

I found these as a result of a post on Brian Toss' rigging forum.

https://www.sea-sure.co.uk/configproduct/29-inside-boom-single-line-reefing-block

I recall there's a hole through the aft end of the boom, horizontally. I suspect this was for a clevis pin, to which the aft ends of the clew lines were attached.

Now, to find an appropriate double block to attach to the ring at the top of the vang bracket. Rig-Rite doesn't give a specification.
 

jviss

.
Feb 5, 2004
4,627
Tartan 3800 Westport, MA
I completed the rigging of this, this weekend, with the shuttle blocks mentioned, and 175' of 3/8" New England Ropes Sta-Set. Works great.