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Old 03-09-2008, 16:10   #16
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The "T" stands for temper. 6061-T6511 is the same as 6061-T6 except that it is stretched after solution hardening. That does make it stronger than 5083/5086 and I admit it is used in aircraft structural parts but it does not improve corrosion resistance. The alloy content remains the same with copper being the primary hardening additive.

Mast are made from 6061 because of it's strength but not for it's corrosion properties. Except for the very base, the potential for corrosion is lower in masts than chainplates and they are easier to inspect. Chainplates OTOH are usually buried in the structure where especially the back side can't be inspected easily and where moisture may accumulate so corrosion resistance take precedence over strength.

BTW, I did say "unless weight is a critical factor". You are referencing Olympic racers and in that case weight is critical. But remember the axium that if a racing sailboat doesn't fall apart just after crossing the finish line it was built to heavy.
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Old 03-09-2008, 16:50   #17
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If you don't think T6511 is aerospace/spaceage why don't you come up here and visit a small local company, Boeing. I'd be happy to set up a tour.
Perhaps I would see some stainless steel too? That being used where it is the most appropriate material for the service.
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Old 03-09-2008, 17:00   #18
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Some stainless, but weight to strength ratios and lack of flexibility (failure) come into play when using it. My point is there are alternatives out there, and some can cost less.
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Old 03-09-2008, 17:19   #19
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You didn't pick up that my "Perhaps I would see some stainless steel too?" was rather tongue in cheek then?

I agree that there are many alternative materials that may be able to be considered for a particular service (including composites being used for quite some years now for chainplates). Don't think anyone has disagreed with that - just perhaps posting along the lines that the selection should be made by those who know what they are talking about and I suggest some who appear to know more about that with respect to chainplates than you do have passed on some advice which you have chosen to ignore.

Which, as I have said is fine, 'tis your boat - just others may consider a little more the ramifications of your invitation to follow you. But I think that my making of that message is adequately clear so I will leave you to your crusade for aluminium chainplates.
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Old 03-09-2008, 17:29   #20
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Boeing makes the wings and fuselages out of aluminum. But the clevis that joins them together is steel...

Eventually aluminum has cracking issues - remember Aloha? Aluminum is also very soft. That's why it is heat treated and mixed with other elements. We did hands on heat treatment of variosu aluminum structures that we built as part of my metallurgy studies. For a given alloy you can make aluminum harder or softer. Each is a trade off on crack resistance. Harder aluminum cracks sooner.

The boundary structure of alloys is then susceptible to corrosion, particularly intergranular corrosion. A lot of aerospace aluminum is alclad, meaning there is a thin coating of pure aluminum on the surface. This is pure so that it resists (impervious to) the intergranular corrosion - until it gets scratched - hence painting and surface finishing.

As aluminum flexes it work hardens. It also is less resistant to wear which would concern me as a bearing surface - pin to chainplate - probably why boeing uses steel wing fittings.

The right design and selection of aluminum will work fine for chain plates - witness it's already being done - I'd consider bushing the holes. Durability compared to stainless would be my concern. I personally would choose stainless.
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Old 03-09-2008, 17:31   #21
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I think the answer is in your hand... that alum mess is why you are replacing it right?? If you want to save money, buy SS Flat Bar and drill your own or take it to a small shop to be drilled. Theres probably what... 30-35 lbs of SS in 6 plates? Even at $4 per pound thats far less than the trouble of taking them off, rebedding them etc. Just a thought...
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Old 03-09-2008, 18:30   #22
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Why Aluminum Chainplates?

For the sake of the exercise--The reason Easterly's boat had aluminum chainplates is because the short lived Easterly Boat Company was an effort by the Halter Marine Group to enter the recreational sail boat market in the early 70's. Halter--still in business with many small mid-sized boatyards around the Gulf Coast--is/was a builder of mid-sized work boats, light-weight military craft and research vessels. The company also built/continues to build some very high end motor yachts. The company's specialty was/is light weight construction utilizing aluminum. As that is/was what the company's shipwrights knew, it follows that the material they might use in the Easterly's structural applications--and I suspect there are more aboard his boat--is aluminum. It wasn't that the material is less costly, or better, or any of that balony--simply that the company had more than enough off-cuts of fairly costly material that could be inexpensively employed--keeping in mind that the yachts were not designed for, and never intended to become, world girdling voyagers.

I made my original suggestions largely on the basis of offering a resource for inexpensive, high quality, chainplates and merely threw in the comment concerning stainless based upon 40+ years of experience as a structural engineer (orginally an aeronautical engineer by the way) and sailor. Easterly was making an offer of a service to others that was well intended. Adding my two cents seems to have blemished his good intentions. One makes ones choices and lives by their consequences, or not.

FWIW...

s/v HyLyte
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Old 04-09-2008, 17:05   #23
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For the sake of the exercise--The reason Easterly's boat had aluminum chainplates is because the short lived Easterly Boat Company was an effort by the Halter Marine Group to enter the recreational sail boat market in the early 70's. Halter--still in business with many small mid-sized boatyards around the Gulf Coast--is/was a builder of mid-sized work boats, light-weight military craft and research vessels. The company also built/continues to build some very high end motor yachts. The company's specialty was/is light weight construction utilizing aluminum. As that is/was what the company's shipwrights knew, it follows that the material they might use in the Easterly's structural applications--and I suspect there are more aboard his boat--is aluminum. It wasn't that the material is less costly, or better, or any of that balony--simply that the company had more than enough off-cuts of fairly costly material that could be inexpensively employed--keeping in mind that the yachts were not designed for, and never intended to become, world girdling voyager.

s/v HyLyte
HyLyte,

Where did you come up with this information about the Easterly boat company? Myself and several other Easterly owners would like to know. There is very little information about the company available. I do know Mike Brennan, he was a racer, designed the original 30' to be a racer/cruiser. They started production in 1970/71??. They made at least 38 30' hulls and then started making 36' hulls in the mid 70's. I do know of 1 30' hull that went to Hawaii and back to FL. They made at least 14 36' hulls. The company was then sold to Halter because they wanted to get into the sailboat market. Halter stretched the 36' to 38' and made more hulls in the late 70's. I don't know if I would call a company that made 53+ hulls in 9 years low volume for the time period. The USCG has the company sold in early 80's and after that the molds shipped to CA. I find no other information about the Easterlies after that. Yes the boats were lighter, strong and fast. They were never designed to be heavy cruisers, they were just ahead of their time. It is a bluewater boat and I would put the design up against any other of the more modern designed boats. It's built a lot heavier than the Hunters, I would compare it to the Catalinas, but a maybe little heavier.
So it goes back to the debate, heavy full keel, lighter fin keel. (Please let's not start another debate about this).

Flame suit on.........
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Old 04-09-2008, 18:49   #24
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Quote "So it goes back to the debate, heavy full keel, lighter fin keel. (Please let's not start another debate about this). "

I thought this thread was about chainplate material? I think your pictures tell the tale. Corrosion is the issue at hand . I personaly would go stainless. Carbon Fiber if i had too much money. The thought of carrying spare chainplates as a solution is very telling.

Boeing does make great aircraft. My favorite saying is: "Nothing goes to weather like a 747"
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Old 04-09-2008, 19:52   #25
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Easterly,

In re ancient history, I merely wanted to see if I could understand why the original designer of your yacht might have used aluminum structural eliments rather than stainless and/or bronze, so I googled "Easterly Yachts" and "Easterly Boat Works" and thereafter just followed various links to some old SEC filings on Halter Marine and one article on old Gulf Coast Shipyards that led to others. These told the tales, more or less.

An interesting aside to the matter is that we have learned that my wife's cousin, who is located on the outskirts of Chicago, actually took a serious look at an Easterly 38--which he insisted must have been a Cherubini design based upon its close resemblence to the Hunter boats of the same era-- this last Spring. He loved the boat and at $35,000 it was certainly affordable, but passed on it as it wouldn't fit his slip in the downtown marina and he wasn't convinced he could get another, larger one, this past summer. N'any case, they are handsome yachts and I will conceed to your assertion that they are well built. However, given the extent of the errosion of the chainplates in your own photographs, my professional opinion is that the material is inadaquate--but then, that's only one opinion.

Some things to keep in mind. For most people, the boats they own will outlast them (purpose built race boats excepted). Given that, my own "ownership" of HyLyte, and her two predecessors, is/was merely a period of custodianship that was--and will later be--passed on to another. Given my own experience with "Prior Owners's Stuff" my personal philosophy includes the propositions that (a) if something is worth doing its worth doing right; and, (b) don't create a situation or problem that someone else will have to clean up or solve at a later date--or may discover needs correcting at a rather inopportune time. Moreover, in re: eventually selling a boat, every half measure will be discovered and even minor problems will detract hugely from the value of a boat, and commonly far out of proportion to their actual worth.

You made an offer that was well intended. After observing that, I offered a suggestion that was equally well intended that you, or others, might chose to take, or not. I'm not offended if someone choses to ignor my suggestions--heck, my wife's been doing that for decades. Debates and discussions are an exchange of knowledge. Arguments are an exchange of ignorance so, I pass...

And here Homer nods...

s/v HyLyte
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