Hi- Thought I'd remark about the rod and vibration questions. Until about the last half of the 80's we made the rods out of half-inch stainless rod, and retained them at the top gudgeon with a staionless cotter key above and below the gudgeon. The stainless rods were problematic in that they would sometimes gall and get really sticky. If this happens, the only cure is a good polishing with wet/dry sandpaper, then you're good to go for awhile. In the late 80's we made two imp[rovments; we went to bronze rods, which have a low coefficient or friction with stainless and not only slide much better but they have never galled to my knowlege. Wheneve3r you have to replace a rod I'd strongly suggest you use bronze. Thnere are different kinds of bronze and any will do but aluminum bronze and silicone bronze have the best reputations. Monel is also good but very hard to find. At about the same time somebody (probably not me) had the bright idea to have the end of the rod turned down to a half inch and using a smaller hol,e in the bottom gudgeon. This was a worthwhile improvement because the rod could no longer go "bombs away" and drop thru the gudgeons if the operater got careless when handling the rudder. Another helpful comment, if you ever have to replace the gudgeons, is to make sure that they are perfectly aligned when re-installing them. Bolt on the top and bottom ones temporarily, then drop in the rod, stringing the center gudgeon on the rod, and mark and shim the low one. Remove everything, dust them off, then bed and tighten. Don't use silicone; use polyurethane. Rudder vibration is caused by a fat and rounded trailing edge. Slop in the system doesn't help, but the root cause is the trailing edge. If you are having this problem, the best solution is to take off all the hardware from the rudder and get out the sander A power plane will work if you're good with it, but it's pretty brutal. Take the trailing edge down to no more than an 8th inch, and leave the edge flat, not rounded. The water wants to come off the trailing edge cleanly, and not turbulate (pretty good word I just came up with!). Use SPAR varnish to refinish and at least four coats, sanding between each one. (The last time I bought varnish I noticed afterwards that it was was polyurethane. I went back and challenged the saleslady to a fist fight and she told me that all oil based paints have been phased out, possibly just in good old CA. I knew that this happened several years ago with paint, but it now must include varnish. I hope she was lying but she probably wasn't. Bitch, bitch, bitch. jerry ----- Original Message ----- From: "James Poulakis" <picfo@comcast.net> To: "For and about Montgomery Sailboats" <montgomery_boats@mailman.xmission.com> Sent: Saturday, September 27, 2008 12:11 PM Subject: Re: M_Boats: Singing Rudder
Thanks Gordon,
Spirit is less then a year old and is equipped with the stepped- diameter rudder rod. Still, the rod may be a contributer to the harmonics, so next time I'll check this more closely . Hey, there's nothing more fun then hanging over the stern and fidgeting with rudder parts while sailing down a narrow, crowded channel right?
Jim M17 "Spirit"
On Sep 27, 2008, at 7:12 AM, Gordon Gilbert wrote:
Hi, Jim: I just experienced a similar thing on a sail yesterday. In my case (I'm not sure if your setup is the same as my 1983 model), the steel rod that the rudder hinges on had ridden up when I raised the rudder previously. Then when I lowered it, the rod did not go down completely with the rudder, leaving the rod short and out of the lowest gudgeon (right word?). This has happened before, and when I pushed down the rod completely (so the cotter ring can't go any lower) the humming went away. I determined yesterday that I just need to ensure that the rod goes all the way down with the rudder every time I lower it for a sail.
Have a great weekend!
Gordon M-17 "Sapphire" Milwaukee
On Sep 27, 2008, at 2:20 AM, James Poulakis wrote:
Sailing even with a moderate breeze makes Spirit's rudder hum loud enough to drown out the Pillar Point fog horn. The rudder is new and doesn't seem to be warped. Is there a trick to stop this or is it just a Monty thing?
Jim Poulakis "Spirit" (M17)
_______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
_______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
_______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
-- Internal Virus Database is out-of-date. Checked by AVG. Version: 7.5.524 / Virus Database: 270.7.0/1680 - Release Date: 9/19/2008 8:25 AM