Doug, Is Navy Brass bronze? If a new CB were to be cut from stock using a CAD file, would the lead and trailing edges have to be shaped, or it the existing board just a flat section of metal? What about having the board cast in a different metal? Would that be prohibitively expensive? Thanks, Craig ----- Original Message ----- From: "Doug King" <msog@msog.org> To: <montgomery_boats@mailman.xmission.com> Sent: Sunday, February 24, 2002 9:38 PM Subject: M_Boats: Centerboard Two suggestions: 1) Go to "Other Resources" -> "Search List Archives" on the MSOG site. Two searches will cover the topic, type the word "galvanize" in the first search term box, and "centerboard" in the second search term box. You'll get several hits. Then, go Back and use "CB" instead of "centerboard" for a second set of messages. There's quite a bit of discussion on this subject, but not sure any consensus was reached. Message six under the second search (galvanized and CB) by Howard Audsley discussed the possibility of getting a CAD file (probably a .dxf) made that could be used to get steel, or Navy Brass or SS if you're rich, boards cut more cheaply. If there's enough interest, maybe it's worth a bunch of people getting together to pay for a CAD file to be used by anyone who needs it. I'd go in on it, and it could be downloaded from the MSOG site. 2) The Potter people talk about having decent results galvanizing their CB, which are steel (Montgomerys are originally cast iron on the older boats, FG later on): "One of the things that has become popular (and standard equipment) on the Potters is a galvanized centerboard. When I had my P-15 I was planning to have the centerboard galvanize dipped when the paint gave out. My board was a slab of steel... Don't know if it can be done with cast iron. Anyway, for what it's worth, the Potter Yachters seem to have good luck with the galvanized boards." Maybe someone who subscribes could write to their listserver and see what works best re: painting galvanized, etc. Unless Bob Eeg, Jerry M., or Judy Blumhorst want to just tell us... ;) Doug At 06:45 PM 2/24/02 -0500, you wrote:

I'm sure this question has been addressed exhaustively in the mailing list archives, but I've never had much success accessing them.

Is it possible to galvanize the older M17's centerboard? If so, has anyone out there done so?

Would galvanization be preferable to epoxy painting? I imagine epoxy painting and filling would be cheaper and would make faering easier.

Would galvanization be prohibitively expensive?

Would galvanization give complete corrosion resistance?

Thanks!

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------------------------------------------ Doug King M-17 #404 "Vixen" Montgomery Sailboats Owners Group Web site: http://msog.org Email: mailto:msog@msog.org

For cast bronze I would refer you, again, to Roger Winiarski (http://www.bristolbronze.com), but he's not in the Midwest and I don't know if he could beat the stock bronze price. But, again, Roger's is a very pure alloy that would outlive any of us, even in a saltwater environment. Thanks for the details! ----- Original Message ----- From: "Howard A" <haudsley@tranquility.net> To: <montgomery_boats@mailman.xmission.com> Sent: Monday, February 25, 2002 8:02 AM Subject: M_Boats: Centerboard Honshells wrote: Doug, Is Navy Brass bronze? If a new CB were to be cut from stock using a CAD file, would the lead and trailing edges have to be shaped, or it the existing board just a flat section of metal? What about having the board cast in a different metal? Would that be prohibitively expensive? Thanks, Craig The "navy brass" term might have originated with me. After considering several options other than steel or cast iron, I was told I could order bronze plate and have that cut out to shape. The steel shop's term for bronze plate was navy brass, but I'm not sure what the alloy content of that would be. It sounds different than silicon bronze. At any rate, the cost for the size I needed was nearly $1,000....before having it cut. I think the ultimate solution is to use cast bronze, like Bob is doing for the new M23, but I have been unable to find anyone in the midwest that can fathom the idea of casting something that big. The least expensive solution is to use reglar plate steel and have a machine shop with precision gas cutter cut out the outline, then shape it by hand. The leading edge of the cast iron boards has a blunt bullet shape or slightly thinner profile than a half round shape, and the aft 3 or 4 inches is tapered to maybe a 1/4 inch. These tapers apply only to the triangle shape of the board that is actually exposed when in the down position. Howard _______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats

Just to pass this over to Howard, herewith his posting I referred to: "In addition to looking for someone to sand cast a bronze board (never even got to price...could never find anyone in the midwest who would do it...they can build 20' sculptures..but not a CB?). I checked with a local welding shop. They were going to be able to cut a new cb out of plate steel with a computer controlled gas cutter, from a CAD drawing. They said that once the drawing was done, anyone with similar software, which most of these shops seem to have, could cut one out of plate steel. Having it done locally would probably be the cheapest, to avoid shipping costs, which right now are sky high. You would then paint and treat the carbon steel board as if it were cast iron, with all the rust problems that go with it. The time involved to measure and draw the board on the CAD program was about $100. Cost for the board, as I recall, was about $200 for plate steel. Cost for the same thing in stainless was about $900 or more. Cost for the same thing in Navy Brass (Bronze?) was about $1,500. You could also do a galvanized steel board for about $400, as I recall. Don't know how or if antifouling paint would stick to the galvanized. Somebody may also know of some other exotic metal or metal treatment that would work. The most important thing would be to have someone measure an old board, then do the CAD drawing in the file format the gas cutters use, then have that file available to take with you on a disk to shop locally. A bulk order thing might work if the price discount is greater than the cost of shipping. It might also be best if one shop learns how to do it right, with the right bevels, etc. Plate steel is also slightly heavier than cast, and you might be able to drop down to 5/8", vs. the 3/4" cast, to make it easier to fit in tight trunks. Especially with bottom paint on it. I would be happy to offer mine as a pattern, but the board is still in the boat, and I don't intend to take it out again this year. Only to drop it down to clean it and maybe add another coat of paint. But it's for an M17. That won't help the M15 owner." - Howard At 10:15 PM 2/24/02 -0500, you wrote:

Doug, Is Navy Brass bronze? If a new CB were to be cut from stock using a CAD file, would the lead and trailing edges have to be shaped, or it the existing board just a flat section of metal? What about having the board cast in a different metal? Would that be prohibitively expensive? Thanks, Craig

------------------------------------------ Doug King M-17 #404 "Vixen" Montgomery Sailboats Owners Group Web site: http://msog.org Email: mailto:msog@msog.org