[C38] Stanchions
Chuck Finn
charles at finn.ws
Tue Feb 1 09:28:50 EST 2011
Anders and Steve,
I was a tool and die machinist for U.S. Steel way back in the 70-80s.
And you know what we machinists say about engineers!
Regardless, this takes Steve's "out of date" to a whole new level!
But, Anders back of the envelope calculations need to be compared to the
strength of a 4 square inch plate attached to the deck with 1/4 inch
screws with perhaps 3/4 inch washers on the underside. I would reduce
any estimates by 1/2 due to deck compression, leaks, etc. (that is what
we machinists would do when we have to make the engineer's designs work).
Here are the urls for spec on 6063:
http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MA6063T5
http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MA6063T6
As you can see, there is a big difference regarding the way T5 and 6
spec out.
Best discussion is here:
http://www.asminternational.org/pdf/datasheets/al392.pdf
Max and anyone with the hole problem:
If you want to treat the holes, here is an article about the Alodine
pen. Best price I saw while wandering around was about $80
http://www.aerospace.henkel.com/us/content_data/Henkels_Alodine_871_Touch-N-Prep_Pen_Meets_Aerospace_and_Military_Specifications953433.pdf
Way too much fun for an old man!
Chuck Finn
Mighty Quinn #114
Great Lakes
On 2/1/2011 2:05 AM, Anders Finn wrote:
> Steve,
>
> If you go to the website, and click the image (not obvious I know)
> you'll get a brochure. It says 6063-T5, my dad's abbreviating where he
> should not be when talking about shear strength rather than tensile
> strength.
>
> Spec for 6063-T5 is:
> Al: 97.5% (max)
> Cr: 0.1% (max)
> Cu: 0.1% (max)
> Fe: 0.35% (max)
> Mg: 0.45-0.9%
> Mn: 0.1% (max)
> Si: 0.2-0.6%
> Ti: 0.1% (max)
> Zn: 0.1% (max)
> other: 0.05% (max each)
> other: 0.15% (max total)
>
> Anders
>
> On 01/31/2011 10:28 PM, S Orton wrote:
>> Did the tech at Taco Marine tell you what material the rail extrusion
>> is? I always assumed it was a 6000 series which is not a very
>> strong, but is weldable, free machining and has good corrosion
>> resistance. 6061 can have up to .7 % of iron in its alloy. I've
>> been retired from the aircraft design for 13 years and to me T5/T6 is
>> not a material, but a temper (strength) condition of the material.
>> Please re-educate an ole dog.
>> Cheers, Steve O
>> ------------------------------------------------------------------------
>> Date: Mon, 31 Jan 2011 23:17:44 -0500
>> From: charles at finn.ws
>> To: listserve at catalina38.org
>> Subject: Re: [C38] Stanchions
>>
>> T5 is a lower cost material than T6. Not as hard or strong, but
>> still some of the strongest aluminum made. It is a bit more ductile.
>> So, is it strong enough to support those torsional forces?
>> Inquiring minds want to know!
>>
>> And Thanks!
>> Chuck Finn
>> Mighty Quinn #114
>> Great Lakes
>>
>> On 1/31/2011 8:15 PM, Anders Finn wrote:
>>
>> Ask and you shall recieve
>>
>> http://tacomarine.com/item--1-9-16-x-1-1-2-Aluminum-Sailboat-Toe-Rail--A62-0009.html
>>
>> According to the tech's at Taco Marine, this is our toe rail spec.
>>
>> Anders
>>
>> On 01/30/2011 12:56 AM, Steve Smolinske wrote:
>>
>> I have worm holes on the aft section of the stbd rail far
>> away from the gates. Good luck fishing that line I did that
>> once took me most of a morning
>>
>> Steve Smolinske
>>
>> Sent from my iPhone
>>
>> On Jan 29, 2011, at 7:55 PM, "Patrick Harpole"
>> <1derful at comcast.net <mailto:1derful at comcast.net>> wrote:
>>
>> *Speaking of stanchions and "worm holes" I got the
>> pleasure of worming a wire through pulpit (aka stanchion)
>> because the bow navigation light wiring failed.*
>>
>> ----- Original Message -----
>> *From:* Max Soto <mailto:maxsoto at gmail.com>
>> *To:* Catalina 38 Listserve
>> <mailto:listserve at catalina38.org>
>> *Sent:* Saturday, January 29, 2011 5:31 PM
>> *Subject:* Re: [C38] Stanchions
>>
>> The weirdest thing is that the worm holes on the
>> rails are not located near a single fastener. Thy
>> are located on the sides of the rails... Most of them
>> on a single side.....
>> Max
>>
>> Sent from my iPod
>>
>> On Jan 29, 2011, at 6:09 PM, S Orton
>> <ssorton at hotmail.com <mailto:ssorton at hotmail.com>> wrote:
>>
>> I should of continued with the "worm hole"
>> discussion, adding I don't consider it a
>> structural problem unless a hole develops
>> at several adjacent fasteners thereby destroying
>> the clamping force between the hull and deck. If
>> it is a hole here and there, fill it with 5200
>> and forget it.
>> Cheers, Steve O
>>
>> ------------------------------------------------------------------------
>> Date: Sat, 29 Jan 2011 13:26:43 -0500
>> From: steve.ribble at gmail.com
>> <mailto:steve.ribble at gmail.com>
>> To: listserve at catalina38.org
>> <mailto:listserve at catalina38.org>
>> Subject: Re: [C38] Stanchions
>>
>> Don't know who made the toerail, but the same
>> cross section is used by several different boat
>> builders of the era so it must be an established
>> extruder...I had the same thing on a 1980 Mirage.
>>
>> On Sat, Jan 29, 2011 at 1:11 PM, Chuck Finn
>> <charles at finn.ws <mailto:charles at finn.ws>> wrote:
>>
>> Steve,
>> I called Garhauer yesterday about stanchions
>> and the toerail. Mike told me they never
>> made the toerail as that is not something
>> they are set up for. He was interested in my
>> idea of a toerail stanchion, but would make
>> no comment until he had seen what our toerail
>> looks like. He offered to work with me on
>> this after I got him some specs/pictures of
>> our rail. Does anyone have a cross-sectional
>> view and/or measurements?
>>
>> If I were to guess, I would say our toerails
>> were made of T6 aluminum as it extrudes and
>> anodizes well and is one of the hardest and
>> strongest types. I have cut this stuff on a
>> lathe and it does not remotely behave like
>> ordinary aluminum! You need ear
>> protection. I agree with Steve O. that low
>> bidder could be our problem here, which of
>> course would vary by batches and years. All
>> aluminum I am aware of can contain some small
>> levels of iron, but I recall Grumman
>> successfully figured out how to reduce this
>> back when they were the aircraft frame
>> folks. By the way, don't try to weld on this
>> stuff as it requires TIG and a lot of
>> practice! One more thing, aluminum can
>> corrode when exposed. The neat thing about
>> this stuff is it almost immediately begins to
>> form an impermeable skin as part of the
>> corrosion process that essentially stops
>> further corrosion and it is able to do this
>> across a wide PH range. Now you know pretty
>> much all I know about this stuff!
>>
>> Regards,
>>
>> Chuck Finn
>> Mighty Quinn #114
>> Great Lakes
>>
>> On 1/29/2011 12:19 PM, S Orton wrote:
>>
>> Phil, I don't think a backing plate is
>> worth the effort- the underside
>> clearance/access is very tough. Use
>> oversize washers if possible. If the
>> holes are rotted out, fill with epoxie
>> and redrill. My toe rail also has worm
>> holes, near the gates. I assumed the
>> reason was low bidder on the extrusions
>> with much more impurities included. The
>> aircraft specs would preclude what we a
>> seeing. Has anybody contacted Garhauer
>> about this problem? I can understand
>> corrosion at the SS fasteners, but these
>> worm holes appear unrelated.
>> Cheers, Steve O
>>
>> ------------------------------------------------------------------------
>> Date: Sat, 29 Jan 2011 10:09:44 -0500
>> From: steve.ribble at gmail.com
>> <mailto:steve.ribble at gmail.com>
>> To: listserve at catalina38.org
>> <mailto:listserve at catalina38.org>
>> Subject: Re: [C38] Stanchions
>>
>> Great thought about the backing plate,
>> Phil. I've always considered stanchions
>> and lifelines to be expendable in the
>> event of emergencies...that they were
>> basically to break your fall, not
>> necessarily there to support the weight
>> of the world. That said, obviously I/we
>> don't want to replace these things every
>> month or two so they need to be stout
>> enough. It seems like one of the first
>> things to go, when looking at the entire
>> stanchion "system" is the through-bolt
>> hole (as Phil indicated) and that a
>> backing plate would disperse the
>> loads/forces among the 4 bolts/holes
>> rather than the two that experience
>> expansion when torque is applied the the
>> stanchion. Long story short, assuming
>> we're all not going to run out and
>> replace our stanchions for another
>> design, that Garhauer already has the the
>> backing plate (the base prior to welding
>> to the stanchion tube) so it should be an
>> easy and relatively inexpensive process
>> to upgrade the holding power of our
>> existing equipment.
>>
>> On Fri, Jan 28, 2011 at 8:07 PM, Phil Gay
>> <eyriepg at comcast.net
>> <mailto:eyriepg at comcast.net>> wrote:
>>
>> I thought I would explain what I
>> think I know about metals from my
>> aircraft engineering background. I
>> agree that the toe rail on our C38s
>> is an aluminum alloy. Pure aluminum
>> does create its own oxide coating
>> which retards corrosion. But, when
>> it is alloyed to increase its
>> hardness and strength, it loses the
>> ability to protect itself unless it
>> has a pure aluminum cladding on the
>> surface. Typically these alloys have
>> an anodic coating (the dark surface
>> on our toe rails) or a chemical
>> conversion coating which created this
>> protective oxide on the exterior surface.
>>
>> Near the bow of my C38 the toe rail
>> has started to pit. I don’t think it
>> has progressed much lately with all
>> the rain water that we get here in
>> the NW. I doubt that it has weakened
>> the extrusion much at all. I agree
>> with the statements about the loads
>> on the stanchions. Later model
>> Catalinas have the stanchions that
>> fit into sockets molded into the toe
>> rail as well as being bolted through
>> base plates to the deck. BTW I am
>> pretty sure that the deck area where
>> the toe rails are attached on our
>> C38s is solid un-cored fiberglass. A
>> lot of the looseness of the bases is
>> caused by the rocking of the bolts,
>> and subsequent elongation of the
>> holes, because they don’t have
>> backing plates to hold them
>> vertical. I think that there are
>> ways to securely attach our
>> stanchions to the toe rail if they
>> are also bolted inboard to the deck.
>> I have also thought about having the
>> existing stanchions modified so that
>> they angle outboard to allow more
>> room to pass around the shrouds.
>>
>> Phil Gay
>> C38 049 Que Linda
>> Everett WA
>>
>>
>> *From:*listserve-bounces at catalina38.org
>> <mailto:listserve-bounces at catalina38.org>
>> [mailto:listserve-bounces at catalina38.org
>> <mailto:listserve-bounces at catalina38.org>]
>> *On Behalf Of *Anders Finn
>> *Sent:* Friday, January 28, 2011 4:25 PM
>>
>> *To:* listserve at catalina38.org
>> <mailto:listserve at catalina38.org>
>> *Subject:* Re: [C38] Stanchions
>>
>>
>>
>> Really? I thought that toe rail was
>> aluminum. Should be pretty resistant
>> to salt corrosion. I think what my
>> old man is trying to say is that the
>> toe rail is at least as strong, if
>> not stronger than the plywood under
>> the deck to which the stanchions are
>> currently screwed into. It would be
>> interesting to know the dimensions of
>> the toe rail if anyone has them (I
>> think my dad is going up to measure
>> in a few weeks) and I can figure out
>> what kind of moment could be applied
>> safely to the toe rail if one could
>> find a way to apply the load evenly.
>>
>> Anders
>>
>> On 01/28/2011 04:06 PM, Don Strong
>> wrote:
>> The toe rail really is not that
>> tough. As well, in salty boats as
>> old as mine (1980), the toe rail has
>> some indication of chemical
>> decomposition along the bottom side.
>> I treat my toe rail with care. Like
>> the rest of this wonderful 30 year
>> old device, I hope it lasts longer
>> than I last.
>> Don
>>
>> On 1/28/11 2:15 PM, Anders Finn wrote:
>> Think about pivot point. If there is
>> indeed only two bolts, the only thing
>> keeping it from pivoting is
>> compression between the plate and the
>> toe rail. The bolts are there simply
>> to provide a leverage point. That's
>> what concerns me.
>>
>> Anders
>>
>> On 01/28/2011 02:13 PM, Chuck Finn
>> wrote:
>> This type of fitting is used by:
>> C&C, Hunter, PDQ, Bayfield, and
>> Freedom yachts. I think the
>> footprint is the entire toerail,
>> which is significantly stronger than
>> our pad fastened to a plywood
>> deck.... If I was to worry about
>> strength, it would be the shear force
>> exerted on the bolts if the toerail
>> stanchion base is not a good fit with
>> our toerail... I would weld the
>> stanchion to the base rather than
>> rely on the throughbolt. I can also
>> comment on the strength of at least
>> the C&C toerail as I have raced these
>> boats and that means bounced a time
>> or two off the lines and stanchions!
>> Have crewed Hunters as well, but
>> don't remember the stanchion design.
>>
>> I think my next step will be to
>> contact Garhauer as they are reputed
>> to have first made our toerail. I
>> also could easily fabricate my own
>> bases that would incorporate Ander's
>> ideas.
>>
>> But, will it look pretty?
>>
>> Chuck Finn
>> Mighty Quinn #114
>> Great Lakes
>>
>>
>> On 1/28/2011 4:16 PM, Anders Finn wrote:
>> Yeah, I just got a chance to look at
>> this. I think Steve is right here
>> about a large drop in torsional
>> resistance. However, that being said,
>> those stanchions forward of the
>> cockpit are not really THAT strong. I
>> would like to see at least a three
>> bolt design with a larger outer plate
>> to provide some surface to disperse
>> the torque to the hull.
>>
>> Anders
>>
>> PS. They say they're used on Freedom
>> 32's however, from pictures, I can't
>> see anything resembling a toe rail
>> that would support load on them.
>>
>>
>> On 01/28/2011 12:42 PM, S Orton wrote:
>> Chuck, If I understand the concept
>> correctly, it is a very poor
>> structural design. There is no foot
>> print to react the outward cantilever
>> force on the stantion- you need a
>> four bolt pattern to react this force
>> in all directions and I only saw two
>> fasteners parallel to the toe rail.
>> Cheers, Steve O
>>
>> ------------------------------------------------------------------------
>> Date: Fri, 28 Jan 2011 08:27:31 -0500
>> From: charles at finn.ws
>> <mailto:charles at finn.ws>
>> To: listserve at catalina38.org
>> <mailto:listserve at catalina38.org>
>> Subject: Re: [C38] Stanchions
>>
>> Max,
>> Here is the rigrite url:
>> http://www.rigrite.com/Hardware/Stanchions_&_Bases/Stanchion_Bases_SS.html#SS%20Stanchion%20Bases%20that%20Attach%20to%20Toerail
>> <http://www.rigrite.com/Hardware/Stanchions_&_Bases/Stanchion_Bases_SS.html#SS%20Stanchion%20Bases%20that%20Attach%20to%20Toerail>
>>
>> As you can see, this would put the
>> stanchion on the outside edge of our
>> toerail and would eliminate the
>> base. This would result in a lot of
>> room on the deck. I am thinking of
>> using two of the bases for the gate
>> and then moving forward. My issue
>> about this would look is that I will
>> have to connect to the stern rails
>> and bow pulpit, which would remain as
>> they are.
>> I would also have to fill all the
>> holes in the deck from where the
>> plates were and re-route the holding
>> tank vent, but that would be worth it
>> for the extra room on deck and the
>> elimination of possible leaks.
>>
>> What to our C38 folks think?
>>
>> Chuck Finn
>> Mighty Quinn #114
>> Great Lakes
>>
>>
>> On 1/27/2011 11:21 AM, Max Soto wrote:
>> Chuck, Did you send a link for the
>> rigrite stanchions?
>> Regards,
>>
>> Max
>>
>> 2011/1/26 Chuck Finn <charles at finn.ws
>> <mailto:charles at finn.ws>>
>> One way I know it is sailing season
>> is the scrape on my shin obtained as
>> I climb from the cabin to the
>> cockpit. The other wound is the
>> bruises on the side of both legs as I
>> bang into the stanchions. I love the
>> look of our boats, but the design
>> idea that the stanchions should
>> follow the inward bend of the
>> tumblehome really does not work for
>> me. There just is not enough deck
>> for a guy my size. I am still
>> considering bending and re-welding
>> the current stanchions into a
>> vertical position, but perhaps even a
>> better solution would be to remove
>> the current stanchions altogether and
>> going with a toe rail stanchion like
>> you see on C&C yachts. Rigrite.com
>> <http://rigrite.com/> has these.
>> Attaching stanchions directly to our
>> toerail seems to be a viable option
>> as the rail is really heavy duty.
>> Additionally, you can buy the bases
>> and use the current tubing assuming
>> it is not the light weight stuff Tom
>> has commented on. This would give
>> us a lot more deck space for size 11
>> feet.
>> Just thinking aloud at this point,
>> but I really am tired of the bruising!
>>
>> Chuck Finn
>> Mighty Quinn #114
>> Great Lakes
>>
>>
>> On 1/25/2011 3:25 PM, Max Soto wrote:
>> Good to know that they share the same
>> foot print... If the removable
>> stanchion's base also fits, I'll go
>> for that one next time..... A little
>> heavier, but if they bend, it will be
>> so much easier to replace.......
>> Thanks, Max
>>
>> 2011/1/25 Steven Ribble
>> <steve.ribble at gmail.com
>> <mailto:steve.ribble at gmail.com>>
>> Max, yes...same foot print. Garhauer
>> has a square-ish base that I think
>> are for removable stanchions and a
>> one that's trapezoidal for the
>> solid/fixed type, which is what mine
>> are (also characterized by the "flat
>> top"). I can't speak to the quality
>> comment that Tom refers to, I just
>> know mine have been on the boat for
>> 30 years and only needed to be
>> replaced because the over-wintering
>> force exerted by the shrinkwrap
>> caused them to bend. I thought I saw
>> reinforced/gate style stanchions on
>> their website, but don't know about
>> the footprint.
>>
>> On Tue, Jan 25, 2011 at 12:13 PM, Tom
>> T. <tdtron at earthlink.net
>> <mailto:tdtron at earthlink.net>> wrote:
>>
>> After hurricane Dennis (the Menace)
>> skirted Tampa Bay a few years ago
>> with a near miss, we got tangled up
>> with a piling with the surge and had
>> our starboard lifelines damaged along
>> with the stanchions on that side.
>>
>> I replaced the stanchions near the
>> rail at the aft end of the cabin
>> with Catalina Direct stanchions. I
>> replaced both sides so they would
>> match. My boat had standard
>> stanchions and those stanchions
>> should have been the reinforced gate
>> entry types which are heavier and
>> more expensive.
>>
>> I didn't shop Garhauer and I probably
>> should have but the original
>> stanchions were JUNK so anything was
>> an upgrade! The metal in the
>> replacement stanchions was much
>> heavier gage and with the reinforced
>> foot design of the gate type
>> stanchion there was no comparison
>> between quality or strength of the
>> two types.
>>
>> The reason I bring this up is some of
>> our members may have stanchions like
>> the ones I replaced which may be a
>> disaster waiting to happen. If the
>> stanchions at the front of the gate
>> are like the thin, weak ones like I
>> had they could fail. The thin tube
>> original stanchions may be OK for
>> middle of the lifeline mounts but
>> where the gates terminate they are
>> inadequate
>>
>> Tom Troncalli
>>
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