[Public-List] rigging

Don Campbell dk.campbell at sympatico.ca
Mon Jan 18 08:15:47 PST 2010 

Gord;
Thanks.  What I was quoting was their page of "typical" strengths for 
wire and ropes (none of which they make) and they also say the breaking 
strengths vary greatly by manufacturer. All the more reason to check the 
specs on the roll. Sorting out forces on blocks, never mind block WWL 
and breaking load is always something I find a bit tricky. As for 
winches, I am biased there to Andersens for my current uses, so would 
not consider specs in the Harken catalogue for them either.
Don

Gordon Laco wrote:
> Good morning Don - Sorry I couldn't make it to the meeting.
>
> Be careful with the Harken catalogue when using it as a text for 
> strengths... that company is notorious for phrasing specifications in 
> a manner that can lead one assume an over estimated level of 
> performance (blocks and winch powers in particular)
>
> Gord
>
>
>
>
> On 18-Jan-10, at 10:16 AM, Don Campbell wrote:
>
>>
>>   There has been an extensive discussion on mast beams and rigging 
>> and the pros and cons of various rigging systems. The over-riding 
>> consideration in any refit is safety and it is never the safety of 
>> the conditions that one decides to sail out of port in,  but the 
>> conditions that one gets caught in while out that usually determine 
>> the maximum loading that we put our boats under. It has been shown 
>> many times that boats will take more than people in most of these 
>> circumstances so whatever the designer has done to make boats so they 
>> will weather a storm, they have done a fairly good job. However, they 
>> have done this using design principles which involve numbers and 
>> algorithms that dictate working load limits (WLL) and breaking load 
>> limits. Usually, we do not have those numbers at hand when we make 
>> decisions to repair or replace. The best we can do is look at 
>> materials for sale that seem to match what is there. We can also use 
>> recommended safety factors of 5x for loads not having to do with 
>> lifting people and 10x load if we are lifting people. That sets 
>> breaking loads at 5 x the WWL (so if you tension the rigging to 1000 
>> lbs, you will need 5000 lb wire to be at that safety factor) and 
>> somewhere around 2500lbs if we are lifting people. Oversizing line is 
>> never a problem but it will put the breaking point of the system on 
>> whatever the next weakest link is.(chainplate bolts?)
>>   As an example problem of choices, the Harken catalogue gives 
>> measurements of breaking strengths of three 1/4" SS 1-19 wires: 302 
>> is 8200 lbs, 316 dyform is 8844 lbs and 316 is 7090 lbs. I suggest 
>> that not many of us could tell the difference by looking at these 
>> three wire ropes and I have a suspicion that there are few of us who 
>> could say what Whitby originally put on our boat or what is on our 
>> boat now if we have replaced the rigging..
>>   I have taught the ropes and knots materials for the Canadian Power 
>> and Sail course for a number of years and what I tell my students 
>> every time is to know what you need and know what you are buying by 
>> manufacturers specifications given on the materials that you buy. If 
>> there are no specs given on the roll of rope, then you don't know if 
>> the roll of rope is first grade or seconds. Knowing what you need is 
>> not just 1/4" wire rope. It is what spec on 1/4" wire rope you feel 
>> will be safe ( I'm not a lawyer) for the worst conditions you will 
>> ever be out in and then will that provide the WLL or breaking 
>> strength that the designer has given in his drawings.
>>   I never rely on price to tell me what the value is of the product. 
>> Most often we get what we pay for. There are many times I have gone 
>> to commercial riggers - the people who do the rigging for cranes and 
>> commercial lifting devices - for wire rope because they always have 
>> the specs and usually do not price things with BOAT in mind. That 
>> way, I know what I am getting when I buy wire rope from them..
>>   Therefore the questions that I would ask you to sort out are do you 
>> know the design requirements for the products you are fixing or 
>> replacing? and  does the product you are making or buying meet those 
>> specifications? If the answer for the second is that you don't know 
>> or that that product does not measure up to design requirement,  my 
>> recommendation is DON"T BUY IT!
>>   We have been given 2 figures on rigging in this recent discussion, 
>> $1000, from a source in Florida and $2000 from others. What we don't 
>> know is whether  both  rigging purchases contain the same components 
>> for a start. If one is done with Nico press fitting and the other 
>> with Norsemen fittings, there is one difference. If turnbuckles were 
>> replaced in one but not the other is another significant difference. 
>> Make sure you know what comparative pricing does for you, and if you 
>> do go for a group purchase, make sure you get a well described spec 
>> list before you tender it. That way, your comparative pricing will be 
>> effective.
>>
>> Don #528 and #469
>>
>> Jonathan Adams wrote:
>>> All,
>>>
>>> Mike and I have been communicating regarding a group buy of rigging 
>>> material either fabricated or just the materials. If there are folks 
>>> interested in participating in this, let me know.
>>>
>>> Also note that Gordon Laco has rigging material at great prices for 
>>> A30 members - I got my turnbuckles through him.
>>>
>>> Jonathan
>>>
>>>
>>>
>>>
>>> ________________________________
>>> From: Richard Cronk <manan at nb.sympatico.ca>
>>> To: Public-List at lists.alberg30.org
>>> Sent: Mon, January 18, 2010 7:15:19 AM
>>> Subject: [Public-List] rigging
>>>
>>> Try Mac sails in Fla for rigging ..Got mine there and was  1/4 inch  
>>> with fitting  ..less than 1000;00
>>> D
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