Silica Bronze is actually slightly stronger and more brittle than 316. I
have been told that navy Bronze would be a good choice. I believe that this
is the material which was used on the early Bristol Channel Cutters which
were designed by Lyle Hess and built by Samuel Morris. These were boats of
unquestioned design and construction. Hull #1 of the B.C.C.s is in the slip
next to my Baba. It has the original chainplates and there is no indication
of problems. You are correct the cost is greater but if you like the patina
look, it is the way to go.
Fair winds, blue water.
Rick Williams
S/V Lorac; Baba 30 #71
----- Original Message -----
From: "Sam Boyle" <sboyle # sailjazz.com>
To: "Baba, Panda and Tashiba List" <baba # list.sailjazz.com>
Sent: Friday, May 20, 2005 8:25 AM
Subject: Re: Re:[baba] Re:Chainplate Saga continues...


Just to offer a thought... one way of dealing with corrosion is to factor it
into the specs. Most chainplates could be considerably thicker and the
turnbuckle toggles would still fit. It would be interesting to compare cost
of increasing the chainplate thickness in 304 up to the point that the
toggle will just fit... an extra 3/8" of material is bound to make a
difference.

If you're really after 100% piece of mind then have the new chainplates
fabricated from silicon bronze. It is about the same strength and will not
corrode... in marine applications it is superior to 316 in every way except
appearance... (and cost)

Regards,

-- Sam

SAILjazz -- Bringing Sailors Together
http://www.sailjazz.com/

----- Original Message -----
From: "Rick Beddoe" <sonadora # sail2live.com>
To: "Baba, Panda and Tashiba List" <baba # list.sailjazz.com>
Sent: Friday, May 20, 2005 8:57 AM
Subject: Re:[baba] Re:Chainplate Saga continues...


> I'd be hesitant to compare a C&C with a Baba.
>
> I would be curious to know how you found out your chainplates were 304.
> The metalurgist I talked to said it's virtually impossible without some
> major material tests. One way that was suggested was to use a magnet.
>
> As for seeing corrosion, that's the problem...you don't. Granted, the
> corrosion I saw (after pulling the chainplates) probably happened over a
> long period of time. With 304 how much inspection is required? Do we need
> to start pulling chainplates once a year?
>
> Point loading is certainly an issue. 304 will lose any advantages once the
> 'unseen' corrosion takes hold. As mentioned, the boat was spec'd and
> designed with 316 i.e., designed to withstand the loading the boat was
> expected to experience.
>
> I can certainly appreciate the advantages of 304 from a COST perspective.
> Hell, so they rust out in 5 years...replace them. But do you really want
> to be concerned about saving a buck with something as critical as
> chainplates?
>
>

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Received on Mon May 23 17:15:00 2005