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 Post subject: Centerboard woes
PostPosted: 10 Jun 2013 14:53 
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Skipper

Joined: 21 Jan 2010 12:57
Posts: 168
Well, when I  got the boat to Islamorada, Fl in December of last year, the centerboard functioned just like it was designed to: come May and time to return to Virginia, she be stuck in the trunk. I'm assuming corrosion of the steel member inside the board. Curses on he who made that design decision! So, has anybody used carbon fiber shapes in rebuilding the board to provide the necessary strength and stiffness? Would there be anybody out there interested in obtaining a board so re-inforced? Does anyone have thoughts on providing ports directing water flow from the high pressure (leeward) side to the low pressure side ( as per leading edge slats on an airfoil)? Waste of time? Regards from a boat owner w/too many projects.


 
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 Post subject: Re: Centerboard woes
PostPosted: 10 Jun 2013 16:41 
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Skipper

Joined: 27 Oct 2006 10:32
Posts: 827
I'm not sure why Tartan went with that steel core on the top of the board, except that's where the pad eye is bolted to and maybe a bit of extra weight but the tip of the board has the lead shot that helps gravity drop the board. I guess Tartan thought that it would have a long enough life span and perhaps they never thought that these boats would be around 35 years later???

I think that if I were to start from scratch on this, I would be tempted to go with solid fiberglass for the main body and then add enough lead on the tip to help out. This thig is close to two inches thick and I would think that if it were solid glass, that would be plenty strong to reisist the torsional forces involved.


 
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 Post subject: Re: Centerboard woes
PostPosted: 13 Jun 2013 05:57 
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Skipper

Joined: 21 Jan 2010 12:57
Posts: 168
Well, "Aurora" got hauled yesterday, and by removing the pivot assembly the board was removed. The portion of the board that always stays in the trunk (the top?) was binding. Does anyone know what the bolts holding the pivot pin plates are threaded into? Is it just the fiberglass of the keel? If the threads fail and the board falls out, held by the penant, that would be problematic! Anybody developed a technique to make sure that the pivot assembly stays put? 


 
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 Post subject: Re: Centerboard woes
PostPosted: 13 Jun 2013 10:30 
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Skipper

Joined: 21 Oct 2006 15:36
Posts: 268
I think the bolts thread into an embedded plate. On my boat, the threads in that plate were stripped at a few locations. I redrilled those locations and used slightly larger diameter stainless lag screws. I don't recall the size (1/2"?) by 2 to 2 1/2. They screw into lead and provide a very secure connection. Just bed it well. I did this to mine about 5 years ago and the c/b hasn't fallen off yet?

_________________
Jim Voelxen
Odyssey #191
Home Port: Osterville, MA


 
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 Post subject: Re: Centerboard woes
PostPosted: 13 Jun 2013 12:59 
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Skipper

Joined: 27 Oct 2006 10:32
Posts: 827
They're threaded into something, but I'm not sure if its solid glass or embedded steel. I do know that they are subjected to crevice corrosion:
Attachment:
File comment: centerboard bolts

hinge bolts.jpg

hinge bolts.jpg [ 756.24 KB | Viewed 0 times ]





 
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 Post subject: Re: Centerboard woes
PostPosted: 13 Jun 2013 16:36 
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Skipper

Joined: 21 Jan 2010 12:57
Posts: 168
Anybody thought about boring a hole (3/4"?) all the way athwart the the length of the keel with a pin (shaft) passing through the keel, the trunk and the board? Problematic getting the new hole/shaft alley located and drilled with precision, but I think it could be done. Thoughts?


 
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 Post subject: Re: Centerboard woes
PostPosted: 14 Jun 2013 06:13 
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Skipper

Joined: 27 Oct 2006 10:32
Posts: 827
Conch,
Would this pin meant as a temporary or permanent method for securing the board? I would think that if it is meant to be temporary, it would wind up freezing in place and be a real B!tch to remove. I have heard of some owners glassing over the slot with the board in place, thus eliminating any worries. As you know, the board is really to improve sailing performance and not a stability factor.


 
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 Post subject: Re: Centerboard woes
PostPosted: 14 Jun 2013 06:37 
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Skipper

Joined: 21 Jan 2010 12:57
Posts: 168
I envision this as a permanent "fix": no future worries of the pivot assembly bolts failing. I see the board as a necessary feature: primarily for windward performance and balance but
( I may be mistaken) also to somewhat moderate the rock and roll with sloppy seas and insufficient apparent beam wind to stabilize the boat. 


 
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 Post subject: Re: Centerboard woes
PostPosted: 14 Jun 2013 10:28 
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Skipper

Joined: 27 Oct 2006 10:32
Posts: 827
Oh, I understand now....you want to replace the current pivot assembly with a solid rod that goes through the pivot hole in the board and through the keel....at first I thought you wanted to run a pin through the board to prevent it from dropping, period. mmmmmmmmmm, let me think.... there's about 3-4" maybe at the most between the bottom of the keel to the centerline of the pivot pin and you would need to drill a 1" diameter hole through the keel and have it line up perfectly square as to not have the board angle towards port or stbd. You would be piercing the outer fiberglass skin which might introduce water to the ballast. DO we know if the ballast is solid lead or a lead-resin slurry like they used on the board? I've never drilled into it to find out. If you do it, you would need to use something other than stainless to avoid crevice corrosion, maybe monel? titanium? bronze? I think the wear plates on the board are bronze, if I'm not mistaken so you wouldn't have dissimilar metals. You would want to have the ability to remove this rod in the future for board maintenance........How about other boat builders who use boards, they may have used something similar. Morgan, Shannon, Bristol, Hinckley, Little Harbor, Cambria......so many builders used boards, I'm sure there's a solution out there!


 
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 Post subject: Re: Centerboard woes
PostPosted: 14 Jun 2013 11:07 
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Skipper

Joined: 21 Jan 2010 12:57
Posts: 168
Yes sir, that's what I was thinking. In my younger days, I owned a Glander "Tavanna" (centerboard 33'): a sister boat had the pivot pin fail, the board fell out of the trunk and made for pandemonium until the penant finally broke. It could have sunk her had it flailed around much longer. What I'm talking about would give me more peace of mind than the bolts threaded into who knows what, and and with said threads doing all the work. No doubt I'm over thinking, as SWMBO frequently tells me.


 
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