Trying to understand the new rules - vang key block options

GeoffS

Member
Hi all,

I'm trying to understand the new rigging rules. Specifically, I was wondering if it is legal to simply upgrade the common pre-2000 8:1 vang rigging by 1) replacing the 2:1 cascade loop with a block, and 2) adding a sheave running on the Holt key-block "becket" pin (or shackling a separate block from the pin)?

I'm certain that 1) is OK, but 2) seems to be in a grey area. Have there been any clarifications by the ILCA about this kind of modification?

I actually rigged one of the club Lasers here at the UW using a shackled-on block for 2), and there appears to be enough space for that approach to work (I needed a more powerful vang to help some lightweight students on a windy day). I was planning to take a photograph, but things got hectic at the end of the lessons and I forgot...

Cheers,

Geoff Sobering
145234/DN US 5156
 
You are allowed to use any blocks that fit the dimension criteria in bye-law 1. The only unit you are not allowed to modify is the new lower unit. This would then surely just count as a custom block.
 
The definition of "optional" reads:

"A fitting or block that replaces or is ADDITIONAL to a standard fitting, as allowed by these Rules, and may be
obtained from any supplier."

This would imply that you can add bits to standard fittings (ie key block) to create an "optional" block which is specifically ALLOWED by the class rules.

Therefore, adding a sheave to the standard key block IS legal assuming that is has a diameter of between 15 and 30mm.
 
Many thanks. Thanks was my reading, but I was afraid I'd missed something like "unless it's expressly allowed, it's prohibited"...

FWIW, the combo I put together this weekend seems to work pretty well. I used Harken Bullet blocks, so it looks kind of clunky, and I haven't done the load-analysis to make sure it will hold together, but all in all it seems functional.

Cheers,

Geoff Sobering
 
Another "Holt key-block modification" question:

I've noticed that the sides of my key block are pulling apart at the key end of the block (esp. under load). This is putting some shear-force on the ring-ding holding the unit together. I was wondering if there would be a problem replacing the pin and ring-ding with something like a short 3/16" bolt with just enough threads to fit the nut on (unthreaded in the load-bearing section).

Cheers,

Geoff Sobering
 
FYI, I just did the load-analysis, and a lower sheave in the key-block takes 1/2 the vang load (in retrospect, a big "duh..."). That woks out to about 150 kg at the SWL for the Holt key-block (I believe).

The Harken 303 self-contained sheave is 25mm in diameter and 7 mm wide, with a working load rating of 454 kg and a cost of about $15 US. It would seem to do the trick (the width has me a bit worried, but worst case one could use the block it's based on and shackle it to the pin).

The floating cascade block only sees 1/4 the vang load (ca. 75 kg), so almost any small block will do there.

Cheers,

Geoff Sobering
 
Replacing the clevis pin is fine. I teach kids in Picos which use the same kicker fittings as the "old" style laser rig and last year, two of those blocks sprang apart as the ring popped off the pin. We now bolt them. Again, that would count as an "optional" adjustment.
 
Will Richards wrote:

<<<
"A fitting or block that replaces or is ADDITIONAL to a standard fitting, as allowed by these Rules, and may be
obtained from any supplier."

This would imply that you can add bits to standard fittings (ie key block) to create an "optional" block which is specifically ALLOWED by the class rules.
>>>

[Capitalization was added by Will himself for emphasis.]

I disagree with Will.

Geoff was rightly hesitant. This IS a grey point in the new rules. It is in fact one of the 30+ ambiguities on my list, and it still has not been clarified by the Chief Measurer.

Will's mental error above stems from taking the DEFINITION of the adjective "optional", and pretending the rules thus allowed "additional" everything in optional items.

Will's error is actually caused by ignoring the very beginning of this definition. The full text of the definition in Rule 3(a) is:
<<< [An] "Optional" fitting is a fitting or block that replaces or is additional to a standard fitting, as allowed by these Rules, and may be obtained from any supplier. >>>

This rule only sets how the term "optional" will be interpreted in each rule. It does not itself set WHAT can be ADDED, nor WHAT can be REPLACED.

It's the other articles of the Rules themselves which specify what parts may be be replaced with optional ones. For instance, you can not have an optional "bow eye". Nor can you ADD a second bow eye as an option. That is, the use of the term "ADDITIONAL" in the definition is completely irrelevant for judging WHAT is allowed or not. For that, you need to look at the other rules.

For the blocks in a vang system in particular, Rule 3(d)i says: " The vang system ... shall be comprised of ... and loops and/or “Optional” BLOCKS for additional purchase..."

Rule 3(d)i is clear: What is on option here is a BLOCK, not a sheave! In Rule 3(d) about the vang, an "Optional vang key block" is mentioned, for instance, but not an optional SHEAVE. An "Optional swivel" is mentioned, for instance, but not an optional SHEAVE!

The question then boils down to whether customizing an existing key block by adding a sheave to it makes the resulting gizmo an "optional block". And that's where the definition of the rule makers needs to be consulted.

In this application, the definition above simply becomes:
" An Optional BLOCK is a BLOCK that replaces or is additional to a standard BLOCK." Period!

The term "replaces or is additional to" here simply refers to the usage in a rule: if a rules alllows REPLACING a block, then the definition is read only as "a block that replaces a standard block." If a rule allows ADDING an optional block, then the definition is read only as "a block that is additional to a standard block".

That is, the term "additional fitting" in the definition is used solely to cover the "additional" items like the "additional blocks", "Optional camcleats", "optional swivel", "optional quick release system", "optional tiller retaining pin" referred to in the other rules.

Then, the only determinant of whether you can add a sheave to the standard key block is simply whether the resulting conglomeration satisfies the definition of an "optional block".

And at that point, we face the requirement in the definition that the optional item "may be obtained from ANY SUPPLIER (and nobody else)"!!

Consequently, the main issue is whether YOU are a supplier yourself! That is, can you "customize" a block to make your own block, passing yourself as your own supplier?

On a grander scale, the issue is whether a Mechanical Engineering Ph.D. at MIT with access to university labs, funds, staff and manufacturing facilities can design and make his own custom Laser blocks and claim "I supplied it to myself"? Or exactly what constitutes "a supplier"?

To put it more bluntly, are our new rules allowing customization at the sailor level to open Lasering to a situation where those from technologically more advanced countries are allowed to have an edge in the performance of the parts they use compared to those in countries not so well endowed? Does this rule make the Laser an experimental class with respect to certain parts designs?

This is a MAJOR question that was addressed by the World Council. It was addressed, but no clarifications were posted. It's not a simple decision.

This has been discussed greatly on the Mailing List, too. I am surprised Will Richards did not remember it!

My personal opinion is that the rule makers used the term "supplier" for a reason. Also IMHO, if adding sheaves to the standard key block is to be allowed, this must appear as an expliit allowance in Rule 3(d)vii. The definition of "optional parts" should not be relaxed. In fact, it should be tightened.

And until a public clarification is provided by the Chief Measurer, we should protest anyone who tries to customize his parts in ways not explicitly allowed in our rules.

Best,

Shevy Gunter
 
"Additional"...

<<< [An] "Optional" fitting is a fitting or block that replaces or is additional to a standard fitting, as allowed by these Rules, and may be obtained from any supplier. >>>

I agree that adding a sheave to the standard Holt vang key block pushes the envelope of the rules a bit and is probably a bad thing. After persuing the rules in a bit more detail, one of the more consistant aspects is that everywhere [I could find] that a sheave is mentioned it is as a part of a block. This would appear to preclude adding a bare sheave anywhere, period.

However, I see nothing in the wording of the rules that would prevent hanging an additional block off the becket-pin on the standard Holt key-block. In this situation, there is lots of room so this works just fine.

The main reason I believe this would be considered an acceptible configuration is twofold. First, there is no "modification" of the std. key-block involved; if one got really picky, it would be possible to tie the block to the pin using a short length of line - there is clearly no prohibition against tying line to the pin, and no prohibition against tying "additional" blocks to the end of pieces of line. Secondly, this is really just a friction-reducing adaptation of a long-standing configuration of the standard vang blocks, which would appear to be well within the intent (if not the text) of the new rules.

Hopefully, the Class Measurer will provide some more detailed interpretations soon...

Barring an unexpected influx of cash that allows me to purchase a Harken vang, I should have such a rig when I race in the Badger State Games here in Wisconsin. Since there's no chance I'll place in the silver there, perhaps I'll have someone protest my vang and use that as a mechanism to have some clarifications issued... ;-)

Cheers,

Geoff Sobering
 
Geoff,

It is my understanding that it is perferctly legal to SHACKLE a separate block to thre bottom of the standard vang key block.

Shevy
 
Having no read Shevy's post in full I see what is being said. I do indeed the recall the length mailing list thread(s) relating to the issue of whether you can call yourself a "supplier". I think that the point to consider, in absence of any ILCA or local rulings on the issue is not whether any fitting breaks the a specific rule because as in this case, the rules are "grey areas" but refer instead to the fundamental principle of the ILCA rules. It is my opinion that where the ILCA cannot clarify such ambiguities, we (as sailors and the people who make the laser class what it is) have to decide. After all, sailing is a self-policing game. If such systems are protested, all the committee can go on is the fundamental laser one-design principle. Therefore, maybe some questions should be asked of the controversial rig:

1) Mechanically, does it offer the same performance as another system generally accepted to be legal?

And if the answer to 1) is no:

2) Is the variation in performance a significant one.

I realise this is not a desirable position to be in. The answer to question 1 is a simple yes or no. The answer to question 2 is less discrete. For example, if a system has the same mechanical advantage and setup as another but uses a modified key block as detailed in this thread, performance may be effected. Not the mechanical advantage performance but the SWL and break load performance. Does a 5kg SWL increase constitute a "significant performance difference"?

I feel that in the absence of official clarifications, the best we can do with borderline rigs is to ask ourselves if there is actually any practical difference between say a Holt double with pin head or a Holt "standard" single w/becket with a sailor-added sheave.

When we have no official word, are we in a position to judge borderline rigs?
 
IMHO, it's not all that unusual to see this kind of churn and uncertainty happening after a dramatic change to the rules like this. No organization's going to get it completly right the first time; that's where the idea of "case law" comes into play with the evaluation of specific situations by the appeals process, and the issuance of clarifying statements. Like Shevy, I'm a bit surprised that the class hasn't issued any preemptive clarifications and ammendments, but what the heck... FWIW, the other sailboat class association I'm a member of (DN iceboat) has just discovered that there is no longer a source of sailcloth that meets the specifications in the class rules...

On the Olympics front, isn't all the Laser equipment supplied by the organizers?

Cheers,

Geoff S.

P.S. I've attached a photo of my modifed Holt key-block (actually, on my boat right now, the 3/16" pins have been replaced with #10 machine screws... as soon as I can make it, the top pin will be replaced with a 3/16" SS rod threaded only on the ends for more strength - that's all mostly because my key-block has seem *much* better days and the side-plates are quite distorted).

The improvement over the pre-2000 rigging is amazing! Much easier to adjust in both directions. The only changes were to: 1) replace the bowline knot cascade turning-point with a Harken 224 Microblock and 2) replace the key-block becket-pin turning point with the Ronstan 20100 block. I even used the old line! (I did have to slide the points where it locks on the cleat-block to account for the difference in the dimensions of the new hardware). So, for about $14 (US) I think I have a rig that's a major improvement, and should get me through until I can afford a Harken vang. I'm sure the two blockswill find a good use somewhere else, too.
 
All Olympic boat are supplied by the local manufacturer but I'm not sure if competitors are allowed to modify the boats in any way.
 
Vang Question - replacing "vang block with jam cleat"

Could someone clarify a point for me? I know I can replace the "vang key block" with a non-Laser custom block (meeting the rules criteria about diameter, etc). But can I replace the "vang block with jam cleat" with a non-Laser custom block?

I have a nicer vang block from a larger dinghy that I would like to use, but I've been given the impression that for the cleating block, I must use only a builder supplied (old or new style) block.

Anyone have a short answer to this?


I've been to Dr. Laser and other FAQ sites, but this remains unclear. The rules answers seem to be evolving over time, but much of the web material is dated (Laser International.org rules explanation is 2 years old!!).
 
> can I replace the "vang block with jam cleat" with a
> non-Laser custom block?

So far as I can tell, the short answer is: "No"

The longer answer is, well, longer...

The rules (from http://www.laserinternational.org/rules/bylaw1.htm) seem pretty clear about what you can do in a mix-and-match sense with the cleat block in the vang. The basic description of the vang is:

- 3.d.i) The vang system shall be between the mast tang
- and the boom key fitting and shall be comprised of the
- vang cleat block, the vang key block, a maximum of two
- control lines, loops and/or “Optional” blocks for additional
- purchase with a maximum of 7 “Turning Points”.

So far as I can tell, the phrase "vang cleat block" unambiguously refers to the Holt HA165 block and the "vang key block" is the Holt HA93.

Lets look at rules that mention modifications to the assembly:

3.d.vii specifically allows the replacement of the entire "vang key block" with an "'optional' vang key block", so we know we can toss the HA93 if we want.

3.d.viii specifically allows adding blocks to the sides of the "vang cleat block", but does not allow replacement of the "vang cleat block", so that's no help.

3.d.x allows the replacement of the "vang cleat block" with either one of two "builder supplied" assemblies.

It would appear that the dread "supplier" designation isn't an issue for the cleat block (unlike the other blocks).

So, the complete set of allowed cleat blocks would appear to be:
1) A HA165 with or without "optional" blocks on the sides
2) The Harken new cleat-block
3) The Holt new cleat block

Perhaps someone else will have access/knowlege of more recent class activity or rulings that might clarify things...

Cheers,

Geoff Sobering
145234/DN US 5156
 
You have a limited choice:

The "classic" plain bearing Holt alloy jammer OR the Holt "new" lower unit OR the Harken "new lower unit.

Simple really: the Laser one - (or two or three) - design....
 
Missy James wrote:
> I've been to Dr. Laser and other FAQ sites, but this remains unclear.

It's all there in black and white, Missy!
See "Designing Your Custom Vang" in the drLaser web site, which explicitly states:

"If you want to get rid of the original jam-cleat system, you are required to purchase one of the builder supplied lower vang assemblies "

The full paragraph reads as:

"Note that there is no allowance for blocks with integral cam cleats! In fact, the new rules allow only single blocks to be added to the original Laser vang cleat block. This effectively prevents you from rigging your own vang from stratch! Any customization you will do on your vang will have to be by adding optional parts to or replacing the top (key) block in the existing (original) Holt Laser vang. If you want to get rid of the original jam-cleat system, you are required to purchase one of the builder supplied lower vang assemblies - and you can not customize these lower assemblies. However, the new rules do allow for the replacement of the top block and the floating block at the top of the cascade system of the new builder-supplied vangs with optional blocks!"

Editor, drLaser
 

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