Rerigging - breaking stength of 3/8" clevis pins ?

Started by Seadogdave, March 01, 2015, 08:06:44 AM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Seadogdave

I'm in the process of replacing the original rigging on my 1975 Catalina 27.  I am hoping to beef up everything - the next larger size wire, larger turnbuckles, fabricating chainplates to bolt on the hull, etc..  My mast tangs as well as the present chainplates are now set up for 3/8" pins.  I'm planning to go with 7/32" wire.  My question is whether the breaking strength of 3/8" pins are as strong or stronger than the 7/32" wire.  Or, should I just just overbuild them as well?  I want this girl to be able to take an offshore blow!
Seadogdave

Cruiser2B

Seadog,

I looked at Sta-Lok website and they sell 7/32 wire swage and reusable fittings. The 7/32 wire swage fitting were only available in 7/16 pin and the ones you build were offered in 3/8 or 7/16 pin. I would determine what terminals you are using and then see that the pin sizes are. Since you are fabbing chainplates you can make the holes any size you need.

I rerigged my Alberg 30 two years ago and upsized as well. My original rigging was 304 stainless and I put back 316. The new 316 was only marginally stronger than the original 304. If I had stayed with the original size and used 316 it would not have been as strong at the factory installed rigging. Basically 304 is stronger than 316, and i think the material available back in 1971 was also better.

This is just a guess, but I would think the that a clevis pin would have the same shear strength of the equivalent size and material shouldered bolt. Again just a guess.

What you should do is call Rigging Only.com. They are the rigging experts and will help you. They also had the best pricing when I bought mine.

Good Luck
1976 Westsail 32 #514 Morning Sun
Preparing to get underway!!
USCG 100T Master Near Coastal with Inland Aux Sail

ralay

It seems like it would be a no brainer to beef up one's rigging, but I've read conflicting reports of whether it really constitutes an increase in seaworthiness (vs. the designed rigging assuming it is new or in good shape).  Besides the added weight and added windage of larger wire, tangs, turnbuckles, etc., the main caution I've heard is that larger wire will require higher tension.  The increased strain will fall on your mast/deck/hull/etc.  The whole boat was designed as a unit with certain forces/conditions in mind.  My understanding is that most rigging failures are due to age/wear rather than rigging that was not designed to be strong enough.  Is the Catalina 27 known for having poorly designed rigging?  Does it have a history of rigging failures in new rigging?  If not, you might want to carefully evaluate the cost:benefit.  Assuming your current rigging is old enough to warrant replacement, you might consider replacing it with the designed size and saving the extra money to invest in other areas of the boat.  But I'm no rigger, and this is my amateur opinion.  I do know what it's like to have a limited amount of money to spend on many projects, so I'm always looking for proof that we're getting maximum utility for our dollars.  I do second Rigging Only as being very affordable and helpful, whatever you choose.

Grime

#3
If I were think of beefing up my rigging I would wander over to the Catalina forum board and express my thoughts. Do you plan on doing a lot of offshore sailing where you might get caught in a storm? 

With my lack of experience I think I would have my main offshore sail with 3 reefs and a storm jib before I beefed up my rigging. I would insure that my present rigging was in excellent condition.
David and Lisa
S/V Miss Sadie
Watkins 27

CharlieJ

Quote from: Grime on March 02, 2015, 08:31:02 PM
If I were think of beefing up my rigging I would wander over to the Catalina forum board and express my thoughts. Do you plan on doing a lot of offshore sailing where you might get caught in a storm? 

With my lack of experience I think I would have my main offshore sail with 3 reefs and a storm jib before I beefed up my rigging. I would insure that my present rigging was in excellent condition.

Agree totally
Charlie J

Lindsey 21 Necessity


On Matagorda Bay
On the Redneck Riviera

Seadogdave

What a great forum this is!  Yikes - I've put so much thought into this over this past month, I'm getting tired of thinking about it and need to make a decision!  Yes - I have been having an email conversation with Rigging Only (which I heard about through Sail Far) - Very helpful and will be doing business with them. Anyway, I have wondered whether it is worth making all of these changes, considering that Catalina has probably engineered the system with an adequate safety margin: 3/16 wire has an actual breaking strength of 4312 lbs, the 5/32 is 3310 lbs - that's like being able to dangle my truck off of just one of these wires and it not breaking!  However, like most production boats, I wonder about things holding up offshore when things turn very rough.  It makes great sense though, that I expect most rigging failures are age/wear related with a failed component.  Then too, I never considered the extra strain on the mast/deck/hull, if there is higher wire tension.  Then there is that persistent leak at the chainplate entry onto the bulkhead. But I love the sailing characteristics of this boat and putting outboard chainplates onto the hull side will sacrifice some of the angle of attack to close windward beating. Then there is the time factor - I got so many cool projects (rebuilding an old house, a garden, building a greenhouse, etc.) I'm working on and can't spend half my summer making these major changes, especially living 3 hours from the marina and having a wife to consider.  I'd rather be sailing when I go to the boat.  So ....... now I'm inclined to go with the original rigging design, replacing old components,  and that extra money putting towards an Alado roller furling!  Thank you, mates, for the excellent feedback.  It really helps.
Seadogdave

CharlieJ

Pay very close attention to those bulkheads where the chain plates are attached. And stay on top of the bedding where they go through the deck.

I have replaced bulkheads in 2 customer Catalina 27's from rot due to the chainplates leaking.

On Tehani I had to recore  the decks. I moved the chain plates out to the hull sides
Charlie J

Lindsey 21 Necessity


On Matagorda Bay
On the Redneck Riviera

Seadogdave

Yeah - I've been paying attention to those bulkheads.  I put work into the chronic leak on port about 2 years ago, removing the chain plate, rebedding, and putting a sister piece of MDO plywood where the chain plate is.  I stopped the leak for about a year but now it's as bad as ever.  The rot is only a small area under the deck which I can live with if I get the leak stopped.  The chain plates are presently out.  Surgery is in order.  I'm thinking of grinding out the deck and plywood core , doing a west-system job in that area, leaving about a 3/16" gap around the chain plate, and then fabricating a large deck cover over the chain plate, and caulking the whole plate and filling the gap with 5200.  I'm wondering - are you satisfied with the chain plates on the hull sides?  Do you notice any difference when you are close hauled, as far as sheeting in tight?  How did you ever recore the deck on Tehani?
Seadogdave

Leroy - Gulf 29

FWIW...a poster by the name of MaineSail has most excellent analysis and techniques for rebedding and installation of marine stuff.  It's worth checking his site out.

I don't have access to it here at work, but think the website is

http://www.pbase.com/mainecruising/boat_projects

Well worth your time.

Leroy

CharlieJ

Completely satisfied, however. Moving the chain plates on Tehani was only a 3 inch move, so very little effective sheeting change.

I recored from below- large sections. Boat had been abandoned in a Upper NY state yard for some 15 yrs

Here's a link to Tehani's gallery on this site

http://sailfar.net/gallery/thumbnails.php?album=20
Charlie J

Lindsey 21 Necessity


On Matagorda Bay
On the Redneck Riviera

Seadogdave

Hey Leroy - thanks a lot for that link to MaineSail - lots of good DIY techniques - bookmarked it for later reference.  I will apply some of these rebedding principles for the chain plate refit.  Charlie J - very interesting to see the extensive fixing up on Tehani.  That's the kind of projects that excite me the most - a vessel with potential that has been totally neglected. Right now I'm fixing up an old house for a rental that was in similar shape.  Looks like you have one chain plate for each side.  I assume that the upper and lower attaches to it?  Did you go to a larger size of rigging wire? Any other changes, like double forestay and backstay? I had thought about recorring from below under my mast step but decided not to yet, as the deck is still pretty solid. 
Seadogdave

CharlieJ

There  are two  separate chainplates, mounted side by side. stainless backing plates inside. 

Single lowers. Single head and back stay, wire same size as original. Bronze turnbuckles, as originally built. Stalocks on  all wires

Discussed adding double lowers with  Brion Toss. He asked me how long the boat had been sailing with the rig it had?  Boat was built in 1961. I've put close to 10K miles on her since rebuild  ;)
Charlie J

Lindsey 21 Necessity


On Matagorda Bay
On the Redneck Riviera

Seadogdave

Nice to hear you went 10,000 miles!  Did you use SS316, 1/4"  flat bar for chain plates?  Did you have to bend them at all to conform to the hull sides and to the shroud angle? Did you put in any backing plate? I'm thinking of using my existing chain plates (which look quite substantial) by flipping them around the opposite way in case there is some corrosion or weakening I can't see, and mounting them to the hull sides.
Seadogdave

CharlieJ

Reused original chainplates, after thorough inspection. As I said before- added stainless backing plates.  No bend- added toggles under each turnbuckle

On home page there's a section labeled "small boat adventures"  Here's Tehani's. Most of the pic are gone, as is the lady. But you can still get a feel for the cruise

http://sailfar.net/forum/index.php?topic=2504.0
Charlie J

Lindsey 21 Necessity


On Matagorda Bay
On the Redneck Riviera

Seadogdave

Charlie J - Thanks for sharing your adventures on Tehani!  One of the things that struck me was the connections you had with a number of other sailor friends through this web site.  I looked it over last night and recognized many places I too have sailed through when I was a young buck in my 20s (am now 61).  The longest trip I made with some friends was from Astoria, Oregon, down the Columbia River to Portland, trucking the 30' S2 to New Orleans, sailing to Clearwater, FL, thru the Okechobee Waterway, crossing the Gulf Stream to the Bahama s, island hopping to Haiti (where our hull split open and spent 2 months at anchor), and then to Dominican Republic and over to Puerto Rico.  Prior to that I had shipwrecked my Kittiwake 23, 55 miles off the coast of New Orleans, running aground on an island at 2 in the morning after a week of a northern (30 knot winds) and 10 foot seas.  This was in the days prior to GPS.  The following chapters of life involved settling down with a wife, building a house, having a career, raising 3 kids, and growing older.  Of course I continued to sail, fixing up some good ole boats, until I finally ended up with this Catalina 27 (from a trade).  The cruising life has always sparked that sense of adventure and never knowing what the next day will bring.  I hope to get back to doing more of it now that I am semi-retired.  How 'bout you, Charlie J?  Are you planning on another voyage? By the way, I used to live in Seabrook, TX on my shrimp boat as well as Galveston with my Kittiwake.  So....... anyway I'm thinking now that I will go with standard size rigging with chain plates on the outside of the hull.
Seadogdave

CharlieJ

 ;D ;D

61?  You're a youngster. I'm 74.

;D ;D


Yes, hoping to depart sometime April, for an open ended trip to west Florida  at least. Any further depends on circumstances. Would love to return to Bahamas, perhaps 2016, with any luck
Charlie J

Lindsey 21 Necessity


On Matagorda Bay
On the Redneck Riviera