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Forums / Restoration / Replacing a centerboard  
The discussions for this thread include the following:

Posted: 07 Sep 2011 at 10:46pm
Having just purchased #204, I need to have a plan to replace a missing Centerboard. I hope to get it up on the hoist this weekend and take inventory of what is up in the well. The centerboard lift cable is not attached to anything and up in the pipe. Where are the pivot pin and teflon bushing accessed?

Are there companies that fabricate a Dolphin CB?
Just a proposal from day dreaming if I were to make it myself: What if you had a 1/4" plate of steel torch cut to the proper dimensions, drill multiple 1/4" holes with throughout, say every 2" and sandblast. This would allow for wood ribs to be epoxied not only onto the steel but have epoxy and SS screws through the holes to hold all ribs tightly in place. Shape the foil with planing and sanding, then 3-4 multiple sheets of 6 oz fiberglass cloth epoxied into place. Fair it and finish with an enamel like Awlgrip.
Would that work? Scot

Posted: 09 Sep 2011 at 7:00pm
I went through the same process about 8 years ago with a stuck center board that turned out to be broken. My pivot pin was located under a lump of fiberglass sticking out from the side of the center board case in the bilge of the boat. I fabricated my own centerboard out of a sheet of MDO plywood, weighted with lead shot cast in epoxy then covered with several layers of 6 ounce fiberglass cloth with stainless steel bushings where the pin and the pennant attach. If I were to do it again I would look at getting a 3/4 sheet of G10 fiberglass and cutting one out of it. Hope that helps, another Scott
Yankee Dolhphin Hull #93

Posted: 16 Sep 2011 at 1:06pm
In that there appear to be variations in the CB design by Yankee, I think I might create a plywood prototype of the design used by #227 to see if we can get a good fit. Cutting the plywood would take all of 30 minutes. I have a hose in place of the tube from the centerboard housing that attaches to the fiberglass "pipe" about six inches above the CB housing. I need to take a scope ( an auto mechanic friend of mine has one)down that pipe to look around within the housing to see the condition of the pin, housing, etc. It takes images with a camera as well. I will report back with my findings.

Posted: 18 Sep 2011 at 12:13pm
My centerboard pin was in the bilge, below the gar-board....the bolt was recessed into some rough notches, and covered with fiberglass. It wasn't hard to find once I started looking.

I ended up repairing mine, I had checked the price of having a stainless steel plate cut for a CB, but it was cost prohibitive. Let me know if you need any other pics of #227s CB, its still out on the table.

Posted: 19 Sep 2011 at 1:27pm
Stainless steel would be very expensive, however if you are treating it with an anti-rust primer, then encasing it in fiberglass, is stainless necessary?

Posted: 19 Sep 2011 at 1:29pm
Is "gar-board" the one between the diner and galley?

Posted: 19 Sep 2011 at 2:12pm
the garboard is what would be the base or floor of the bilge under the dinette/galley...the weird t-shaped hatch....

Take that off, and look down, you will see the top of your centerboard trunk sticking up, and the bottom of that area of bilge is what I call the garboard.

Centered on the T in the centerboard trunk....dug into the garboard is where I found my pivot bolt.

Posted: 19 Sep 2011 at 4:39pm
Okay. The fiberglass bulges out about a half inch on both sides about 3 inches back from the front of the trunk and about 4 inches down. If I cut that off, what will I encounter and how do you pull the pin out once it is exposed. Is it threaded with nuts on both sides or what??
Jonnie, thanks for all the info. You are being a great help to me!!! Scot

Posted: 19 Sep 2011 at 10:06pm
try cutting digging prying....in *mine* there was a 1/2" bolt with a nut on the other side....I had to cut the nut off with an angle grinder, and then there were "channels" that I had to clear the fiberglass/epoxy out of....this channel then allowed me to just get the bolt out using a screw driver to push from the cut end....Canopache dropped her CB last year also, and her pin was higher up.


Eric has a good pic of it.


on mine you can sort of see the digging out I did.
and your welcome....
I'm glad the webmaster put this little place in our world so we could be here for each other!!!

Posted: 20 Sep 2011 at 12:05pm
Excellent! The picture from Canopache is the identical location of the bilateral bulges covering the pivot bolt. Next thing I need to do is see if I can scope the housing with that device that I mentioned and/or get the boat yard to lift my boat to get a good look up into the housing from underneath to assess the situation.Updates and photos to follow.

Posted: 20 Sep 2011 at 11:55pm
and the fun begins....

Posted: 21 Sep 2011 at 12:45pm
Jonnie--I'll pretend that I did not see your last post! Wink What is the maximum thickness of your board ....1 and 1/8"? I have located PTFE lined composite bushings that are industrial strength. How long should it be to fit through the hole in the board and fit within the housing? Scot

Posted: 22 Sep 2011 at 2:44am
Mine was only 3/4 inch thick. I just went down to my local sheet metal place and had them cut me two 3/4 inch long pieces of 3/4 stainless pipe I then drilled oversize holes in the MDO and epoxied the pipe pieces in place so the metal did not come in direct contact with the plywood. Other Scott
Yankee Dolhphin Hull #93

Posted: 24 Sep 2011 at 9:01pm
Same....3/4" at the pivot.

the board gets thicker....but where the pivot is is 3/4"

Posted: 25 Sep 2011 at 7:17am
Good info! I am researching a little on foil design and have decided to use a NACA 006 design which puts maximum thickness (just over 1" 30% back of the leading edge (5 1/4") . Is the CB housing parallel sided from fore to aft or does it taper? Praying for the first option and what is its width? What is the maximum CB thickness it will allow?

Sorry to ask so many questions, but the CB housing is inaccessible on the cradle and the boat is 25 miles away from my home.

Posted: 26 Sep 2011 at 12:03am
the trunk is a box....it doesnt taper...

I don't remember the width....but it may be like 2"

there is room for my board to wiggle around in there.

Posted: 26 Sep 2011 at 2:57am
Mine was about 1 1/2 wide at the bottom as I recall and it didn't seem to have a taper but the sides were definitely not parallel (if that makes any sense)
I'd make a full width test panel and make sure it fit up into in the slot first.

Yankee Dolhphin Hull #93

Posted: 26 Sep 2011 at 7:31pm
I have researched materials that would be stable, shapeable, zero water absorption and strong. Talking about manna from heaven...today a contractor friend of mine and I were discussing the restoration of #204. He can steam form toe railing and fabricate lots of the other teak trim to make things handsome. Not only that , he has a 4' x 5' slab of high density polyetheylene (HDPE) that is 1 inch thick. There is enough to make two, maybe even three centerboards. This is the material that is used in public restrooms between bathroom stalls. He has been trying to find a use for it and he is giving it to me free. Plus we can use his shop planers, grinders, sanders and shapers to form it to the desired shape. The only thing wrong is that the HDPE is.....pink! (It was used supposed to be used in a casino's ladies room). It should weigh in around 75 lbs when finished and has no buoyancy.Tongue What's your opinion guys?

Posted: 26 Sep 2011 at 9:49pm
Sounds almost ideal.

Pink is a spectacular centerboard color...that stuff is pretty slick too so I wonder if any marine growth would be able to attach....I doubt paint would stick well....but my experience with HDPE has been good.

75 lbs seems pretty close to the yankee specs (which we do not have)

I like the idea! it would be its own pivot bushing!

Posted: 05 Oct 2011 at 1:34pm
We are going to experiment on a small piece to shape it with shaving and sanding, then use a heavy duty heat gun to seal the outer surface back to the smoothest finish possible. I doubt paint will stick to HDPE, but if paint doesn't stick, marine growth probably can't do it either. I can always dive under the boat out in the lake with the board down and scrub it with a sponge a few times each season. I will be moving the boat onto its new trailer at the end of the month, so with that lift I hope to have a 1" thick plywood prototype to slip up into the CB well to check fit. I will have the winter to make the CB and install it in the Spring.

Posted: 07 Oct 2011 at 3:10am
I'm interested to know how it works out :)

Posted: 11 Oct 2011 at 4:10pm
I have been busy getting a new trailer for Prodigal so the CB project has taken a back seat for now. Does your design allow for 28" deeper draft with the CB down at the 50 degree designed position and does it extend nearly vertical because there is no stop? Do you know the draft in the fully down position. I imagine that it would give you better upwind pointing performance, especially with a foil design which would create forward thrust.
Returning to the love of my youth--SAILING a Yankee!!!

Posted: 13 Oct 2011 at 12:13pm
I don't know the draft with the board down but it does not drop to 90....

the front of the board acts as its own stop.

the edge that trails away from the pivot hole, will come to rest on the front of the CB trunk.

Posted: 21 Oct 2011 at 10:19pm
Today was interesting. I ended up launching #204 into the water as my marina will be closed when my trailer arrives and the only way to get it on the trailer is by loading it on the ramp. (Latest they have ever launched a boat--a title I could live without) Time to get out the Thick wetsuit. Anyway, putting her on the slings allowed me to see what I had for a centerboard. It broke off above the lift point and is now a ragged, dilapidated stub that does swing freely. Someone cut the CB line tube down to 4 inches above the housing level and stuck a hose with a hose clamp on it. When we were lowering into the water and started to float, water came rushing up the pipe, so we came up and I cut the hose to present a fresh edge and reclamped it and no leaks, but I am very nervous about leaving it like that in the water. Got the mast down too. Don't want this to be a salvage operation.

The other thing I noted was that the waterline that was painted on is way off. The bow area is just below the water and gets higher as you move aft. Gives it the look like it is sinking nose first, but it's not (I hope). This will be corrected when I do the painting of the hull. You can view my album of this boat at http://s1134.photobucket.com/albums/m606/hamdental/

Posted: 26 Oct 2011 at 10:17pm
Hey Prodigal, before you repaint your waterline check to see if your mast is raked forward of horizontal. While measuring for a new sails I found my mast leaned forward so I ended up install about 200lb of lead aft to bring the mast to vertical.
Yankee Dolhphin Hull #93

Posted: 18 May 2012 at 12:33am
Thanks Scott... I have found that the waterline was gelcoat and was the original waterline. I think that balancing the boat once rigged will correct this apparent problem.

Back to the centerboard: pictures will be sent to Ron of the new centerboard that we have created from high density polyethylene. It is non-buoyant, slick as glass, and will not absorb water like a fiberglass board. We have enough HDPE to make at least two other boards. Weight is a little light, 40 lbs, but I don't think it is going to matter. The CB is all about ability to point, therefore the symmetrical foil should maximize this ability. I have loads of pictures to share, just too busy finishing the restoration to upload them. I hope to be in the water on our first voyage on Memorial Day weekend.

Posted: 28 May 2012 at 7:42am
The centerboard is finished, but yet to be installed. The re-installation of all the hardware has taken longer than expected, primarily due to a rotten chain plate that is now better than new, and we are on hold until tonight waiting for the Interdeck to fully dry/cure on the deck grip areas. Tonight I want to uncover the pivot bolt of its fiberglass encasement and back it out.

I had a good conversation with one of the tech reps at Jamestown Distributors in Bristol, RI that gave me the best method for attaching the pinion to the centerboard. I will share that with all when the photos are completed.

Posted: 29 May 2012 at 10:55am
Hi All
Responding to popular requests, a new page on replacing a Yankee centerboard has been posted on the Technical Section/Centerboards

Posted: 07 Jul 2012 at 11:05pm
Well the centerboard has been installed and I have been out twice with #204 in brisk winds of 12-15 knots. The upwind speed and the improved pointing were immediately apparent. The HDPE board is a little light and I am finding ways to add weight to it without weakening the board. The hydrofoil design appears to really help the pointing characteristics. My friend and helper on this project came up with an ingenious way of mounting the pinion wire into the trailing edge of the centerboard using a slot with an inset clevis pin and split ring that does not protrude from the surface of the board.
I am anxious to report back how the HDPE holds up.

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