Replacing standing rigging on a 22' trailer sailer

dlochner · Aug 31, 2022

Follow the manufacturer's recommendation. Find a good rigger in your area and have him make the rigging. Your boat is small so taking the mast down shouldn't be a problem. Install the rigging yourself. There is no need to oversize the rigging.

dlochner · Aug 31, 2022

skipperdee said:
How could I find those? I have the original manuals for the boat but they don't mention anything about load, just turnbuckle sizes.

Work backwards from the turnbuckle sizes and stud sizes. Check with a rigger. Find the specs for a boat that is similar in size and weight.

You might also find some information in the late Brion Toss's book, The Riggers Apprentice.

Edit: And the obvious solution is to measure the diameter of the current rigging.

Scott T-Bird · Aug 31, 2022

It's a very good idea to replace standing rigging that is potentially almost 50 years old! It's really a good thing that you have this in mind. I'm wondering why you are making it into such a production of engineering and analysis. It has already been engineered so why the doubt? If you want it to be heavy duty, simply go up one size from what you have. Some would say that is over-doing it already. Adding thickness increases weight aloft significantly, and if the boat is likely to fail in other ways, the weighty rigging is not going to save it.

If you really want to increase strength and not weight, you should investigate using dyneema rigging. Do-it-yourself fittings is feasible in this case, I believe.

Do you have a swage machine or are you saying that you want to use Sta-Lok or Norseman mechanical fittings? Again, I'm not understanding why you don't just do the normal thing and have a rigger make up your shrouds. West Marine will do it and it won't cost that much. You can easily install the rigging yourself.

The do-it-yourself engineering and rigging production is fine, but, why?

Scott T-Bird · Aug 31, 2022

skipperdee said:
I recently acquired a 1974 South Coast 22 and I suspect the standing rigging has never been replaced. During the off season, my plan is to replace it myself. I want it to be heavy duty... I'm not planning to cross an ocean, but I'd like to rig the boat to be prepared for that kind of thing.

I'm trying to size my new standing rigging and I'm wondering if anyone can offer advice on this:

Is there a way to calculate the working load on my shrouds/forestay/backstay? I read here that the minimum total breaking strength of all the shrouds on one side of a boat should equal 1.0 x max loaded displacement for racing boats, 1.1 x mld for coastal cruisers, and 1.2 x mld for offshore cruisers. Does that sound right?

Following that formula, my boat's displacement is 1800lbs. It can carry a max 505lbs of ballast, so fully ballasted we're looking at 2305lbs max loaded displacement. Calculating a rigging load for an offshore cruiser, that's: 1.2 x 2305 = 2766lbs. But that would be for all the shrouds on one side of the boat, so divide by two and you get a minimum of 1383lbs total breaking strength for each individual shroud.

I'm not sure you are fully understanding that information correctly, plus it is coming from another forum. Read and fully understand the applicable publications, as Dave suggests, but don't rely on second-hand advise found in a forum for amateurs ... not for something like standing rigging. You'll get some good advise if you continue to request it, but be careful if you are not going to take your rigging to a rigger.

dlochner · Aug 31, 2022

Can you post a photo of the turnbuckle end of the shrouds? And if possible the upper ends?

In a typical shroud, the cable is inserted into a stud and a roll swaging tool presses the swage around the wire. The turnbuckle then screws onto the stud. There are a number of different ways to attach the upper end.

Dyneema rope can be used and the initial cost will be lower. However, dyneema is subject to chafe and long UV exposure can weaken the fibers. The most likely place for chafe is where the upper shrouds pass through the ends of the spreaders, a place not easily inspected.

The swages shown in the video can be as strong as the typical rolled swages, however, it must be done with the proper tool that matches the swages or the crimp may not be strong enough. You will be adding $100 to the cost of the project to buy the correct tool.

I have used Rigging Only (Rigging Only) and have found them reasonably priced with good service and quality parts. Mail the rigging to them, they will build new shrouds to match and mail them back to you.

Since you are working with a budget make this a multi-season project and replace one set at a time. First replace the upper shrouds, then fore and back stays, and finally the lowers. In terms likelihood of failing and causing the rig to come down, the uppers are the most likely and lowers the least likely.

Scott T-Bird · Aug 31, 2022

I don't blame you for being resistant to dyneema. Your choice to use 7x19 wire rope seems odd. Is there a reason for choosing such flexible wire? Shrouds and stays are typically made with 1x19. The strands are thicker and the wire is stiffer. The price difference for 1/8" wire is barely notable. True, I was considering rolled swage, for which you would certainly not be buying the machine. That would be the conventional way to make the fittings. The swage sleeves are certainly economical but not a good choice for standing rigging. Aside from being fairly unconventional for a pocket cruising sailboat, the fittings are great for snagging sails and sheets. Chafe protection is certainly necessary. Also, you will need to consider that the shrouds will need to be adjustable. There are additional fittings that you need to consider for making the lengths adjustable.

The rigging will be a one-time expense for this boat. Do it right and you will never have to do it again (and neither will anybody else most likely). A rigger will be responsible for performing the job correctly. Any defects or errors will be at the riggers expense. A do-it-yourself project is all on you. The cost savings for an unconventional product doesn't really seem worthwhile.

jssailem · Sep 1, 2022

You may find some good information to support your efforts here.

Benny17441 · Sep 2, 2022

Just replacing the old rigging with new wires and fixtures will give you the upgrade in reliability you may be looking for. If you have not done it before and do not have the needed tools just hire a rigger to do the job. As an alternative you can take your old wires to West Marine and they will make a new set for you which you could install yourself. The breaking strength of the strands wiring depends on its size. The rigging is tuned to a percentage of the breaking strength. Increasing wire size by itself is no answer. When tuned the wires must be taught while not exceeding the strength of the mast and hull attachment fixtures.

JBP-PA · Sep 3, 2022

My gut feel for a 22ft boat is that 1/8 is too light, I'd go up to 5/32. I've been on some O'Day 22 and the 1/8 rigging felt inadequate. I've seen some Catalina 22's with 5/32, and it seems much more appropriate. I know, not very scientific.
1x19 wire is the usual standard for standing rigging, not 7x19.

Replacing standing rigging on a 22' trailer sailer

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SBO Weather and Forecasting Forum Jim & John

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