Running Rigging Blocks

[Brian @ SV Serenity]

All,

A very quick inspection indicates that the blocks on the mast are...  done.  Several of them are weathered and broken, and one actually looks like it seized and continued to be used and damaged.  I'll be replacing them all, though I'll hold off on the ones I can reach until she's back in the water.  At the top of the mast, forward, there is a U bolt hanging down from the mast cap, and a Schaefer 7 series (2 3/8" it looks like) block hanging from it.  On the mizzen that has what I can only describe as a messenger halyard.  Tiny, like 1/8" or so.  (So nothing keeping the sun from beating down on the plastic--it was the worst of the lot.)  Same setup on the main mast, but no line on it at all.  Additionally, there's a small cheek block, perhaps 1", on the right side of the mast, perhaps 8" down from the mast cap. Looking at the small one, it looks like an after-thought.

No user manual on the site I can see, so I'm looking at the 36 manual.  So the question is, is that monster huge 2 3/8 block with (checks notes) 2750 lbs working load meant to be the messenger (burgee) halyards on each mast?  What is the likelihood that extra block is an extra messenger halyard?  Does that "burgee" block need to be that large?

Brian

SV Serenity

Nonsuch Nereus #003

Pax River, MD

[Bob Neches (Solar Wind, N26C #143)]

Brian,

You might want to take a look at Garhauer (www.GarhauerMarine.com) for better, cheaper replacement blocks than the original Schaefers.

I can't offer any specifics on your boat, but I do know that the factory intent on all the other boats was that the "burgee" blocks be strong enough to serve as a spare halyard block and/or for taking someone up the mast.  I can afford to lose a few pounds, but 2750 lbs working load is more than needed to get me up and down the mast. 

On the other hand, no one has ever been injured as a result of a block being too strong and they may have other intended uses on your boat.

-- Bob

   Solar Wind

   Nonsuch 26C #143

[Joe Valinoti]

I believe that all of our boats have a manual on the website, Brian.  What size is yours??

 

Joe Valinoti
S/V iL Gatto NS30U #221
Sea Harbour YC
Oriental, NC USA

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[Brian @ SV Serenity]

Joe.

Nereus.  40' ketch.

There is a 36 on there, and apparently there was a ketch version, but not the same boat (mizzen is in the wrong spot, and too small).

Brian

SV Serenity

Nonsuch Nereus #003

Pax River, MD

[Brian @ SV Serenity]

Next question:

The various blocks have been replaced at various times.  Half of them have "normal" (round") shackles and the other half have stamped (flat metal) shackles.  Obviously they haven't come to any real harm, but is there a preference in shackle type?

Also, while I'm here, should I be looking for threaded pins and mouse them, or pins with a SS split ring?

Brian

SV Serenity

Nonsuch Nereus #003 (40' ketch)

Pax River, MD

[Elizabeth Powers]

Hi,

I am no expert on shackles but did speak to a rigger when changing the hangers on our 26C.

The hangers are attached with round/cast shackles. The turning blocks for the reef lines and topping lift are attached to the bottom of the boom with flat stainless steel shackles. They are not cast. Cast shackles, round stainless steel of the same strength, are too big to go through the fittings on the loser boom.

The rigger said the flat shackles could be smaller and just as strong as the cast . The cast were larger to compensate for any possible weakness in the casting.

As I said I am no expert.

Rob Powers

Respite 26C #50

Sidney BC

[Bill M]

I have similar issues with the blocks on my mast. I have scoured the NS30U manual and have been unable to find a listing of the blocks. There is one in the NS30C manual but I noticed that the running rigging specified in this manual is larger diameter than what is specified in the Ultra manual. Going on the premise that the loads are the same it looks like a 72mm Lewmar synchro block should work just fine at less than 1/2 the cost of a Schaefer 7 series block. Am I missing anything?

Bill Mortensen

NS30U #335

Summer Song

Noank, CT

[Bob Neches (Me Gusta, Nonsuch 26U #233)]

Bill,

Since the 30C and 30U both have the same size sails, it's not clear to me why the rigging size or the block specifications should differ. 

I was involved in posting the table on the Nonsuch.org website for looking up Garhauer blocks comparable to the original Hinterhoeller specs.  Although I have a 26, I ran the information by several 30 owners who thought they seemed reasonable and were not worried about Ultra vs. Classic differences.   

I've had good experiences with Garhauer, and have never found competing quality for less than their prices.  (That is, when comparing apples to apples.  Garhauer's smallest locking footblocks are twice the size and price of Antal's, so in that case I went with Antal.)

-- Bob

   Me Gusta

   Nonsuch 26U #233

[Mark Powers La Reina 26C Vancouver, B.C.]

I believe what you are referring to as normal round shackles are cast and the flat shackles are stamped. As a comparison Harken rates their 5mm stamped shackle with a working load limit of 567 kg. Their cast 5mm shackle is rated at 540kgs. It appears that at least in the smaller sizes the stamped are stronger than the cast.

Which you choose will in part depend on where you are using the.  In some instances the round shape of the cast will work batter than the stamped shackle because they will line up better. I am helping a friend re do the rigging on his Osprey racing dinghy. In some instances the shape of the stamped shackle would keep the turning block from sitting correctly but there was no problem with a round shackle. 

Originally I thought the shackle pins with SS split rings were the way to go but I have found that in a number of instances lines or the sail would catch on them and work the split ring out.  I now prefer to uses threaded pins and then either use stainless wire or a UV resistant Zap strap to mouse the pin. If the shackle will be taken off frequently I use Zap straps. A quick snip with wire cutters and they come off. I have not had a problem with them breaking. With both Zap straps and SS wire you have to be careful that the ends to not snag on sensitive items such as the sail or human body parts. 

Mark Powers

[Bill M]

Bob,

Thanks for the info, I will look for your table. 

I'm not sure why there is a difference but something else I noticed that was weird was that the NS30U running rigging specs call for 3/16" line for the wishbone chocker and 3/8" line for the tackle yet the 3/8" line has a 2:1 advantage. Is the difference because of stretch or is it a typo? 

Bill Mortensen

NS 30U #335

Noank, Ct

[Mark Powers La Reina 26C Vancouver, B.C.]

Bill,

I think 3/16” is a typo and it should be 7/16” the same as for the 30C

Mark Powers

[Bill M]

Mark,

Thanks, I new it had to be a typo. The 30U manual calls for 3/8" for the 2:1 to the cockpit so that's what I chose. I checked and 7/16" single braid tensile strength is 6500 lbs, double braid is 7,000 and 3/8" double braid is 5100lbs. I don't think anyone in my crew will be putting enough pull on the winch handle to achieve 2500 lbs of tension on the chocker.

Bill M.

[Mark Powers La Reina 26C Vancouver, B.C.]

Bill, it is not the load your cockpit gorilla will put on the line you need to worry about.  It is the load put on the line by the wind and sail once the choker line is tied off. The line may be strong enough but it may be too stretchy. The standing part of the choker is relatively short and stretch there is not too much of a concern. The tackle or running portion of the choker is much longer and stretch can be an issue.  You are beating to win ward in 14 knots of wind so you crank in hard on the choker to flatten the sail and de power it. The wind builds to 16 knots and the tackle stretches allowing more fullness in the sail just when you want it flatter.   You have already cranked in on the choker as much as you can. If you have double braid for the halyard that has probably stretched as well. Now you are thinking of reefing. Because of that I switched both my choker and halyard to Dyneema core dependant line. I also added a Cunningham. Now when I crank in the choker at 14 knots it does not stretch as the wind builds to 16. The halyard does not stretch but I can also use the Cunningham to move the draft forward. 

Samson talks about this in the line selection guide.  https://www.samsonrope.com/docs/default-source/brochures/rm_line_selection_guide_web.pdf

The sails on the Nereus are close to the same size as the sail on the 26. The halyard on the 26 is 110’ long and the choker tackle is 36’. Three percent stretch (not unusual in double braid polyester) equals 3 feet in the halyard and 1 foot in the choker. I want low stretch in the halyard and choker and a bit of stretch in the mainsheet. The stretch in the mainsheet softens the bang on tacks as the boom comes across and gives a bit when a gust hits.

Mark Powers

[Bill M]

Mark,

Thanks for the insight. My worry was about the line breaking but in hindsight I have only seen one line break in 35 years of racing and that was due to a sheave issue. Last year was my first year with the boat and I sailed it with the 3/8" choker without the 2:1 assist as the boat came rigged. I was impressed with how well the boat sailed in 18-20 mph winds without a reef.  I had more trouble trimming the sail in light air than heavy air until I discovered I could use the topping lift to open the leech. Am I doing something wrong here? The cunningham is a good idea.

Bill M.

[Mark Powers La Reina 26C Vancouver, B.C.]

Bill, I also use the topping lift in light air to shape the leech. As far as I am concerned doing so is not wrong. In light air the weight of the boom will pull the leech flat. 

Mark Powers

[Joe Valinoti]

Mark is absolutely correct. 

 

Joe Valinoti
S/V iL Gatto NS30U #221
Sea Harbour YC
Oriental, NC USA

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From: Mark Powers La Reina 26C Vancouver, B.C.

Sent: Sunday, March 13, 2022 10:07 AM

To: INA Nonsuch Discussion Group

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