Any salvaging this centerboard?

Merrily

Merrily

Administrator
I have a friend with a cracked centerboard. He was righting the capsized boat with it and heard it crack. :eek: It has a 6 inch crack from the leading edge just below where it would come out of the bottom of the hull, and perpendicular to the leading edge. I haven't seen it but will ask to do that today, but what do the experts here think? Is there any salvaging this centerboard, and if so, how should he go about it?
 
If it were me, first thing I would do is check w/ dealer or Vanguard to find out where the reinforcing bars are supposed to be, to rule out a manufacturing defect.

If it's not a defect and it has to be repaired, I would use the same method to reinforce the crack that is used for building. Ideally, using a router to put in one or two channels perpendicular to the crack, extending 6 or more inches on either side of the crack. In a pinch, a grinder or a drill press can be used (you can slide the board under the drill press ala a poor mans milling machine since the board material is pretty soft) Avoid going all the way thru the board with these channels

I would also rout out along the crack so there is a channel there for filling with epoxy/thickening agent.

Once the prep has been done, add a little epoxy/thickening agent to bed the rebar, put in the rebar (steel rod, wood dowel, or carbon rod will all work) and the fill up the rest with epoxy/thickening agent. Let harden and flip the blade over, rout out the crack on this side, fill, harden and sand the repaired area smooth.

Marine Tex would be a suitable, if pricey alternative to mixing your epoxy/thickening paste, just make sure you don't leave any voids when filling the channels

Here's a rough pic of the above
Red is the crack
Green is the channel for the rebar
Blue is the area to rout along the crack to fill with just thickened epoxy
 

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  • Blade repair.JPG
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Thanks, 49208. So the way I read it, you rout out two parellel lines to the crack. The routing has to be big enough to slide rebar in to the blade. Also widen the crack so it will take more epoxy. Then slide in the rebar (with epoxy on it) perpendicular to the crack. Then epoxy, dry, and smooth that whole side. Flip it over and only widen the crack on the other side, epoxy, and smooth it. Is this a fair summation?
 
Merrily said:
Thanks, 49208. So the way I read it, you rout out two parellel lines to the crack.
Click to expand...

I'm guessing that was a slip of the keyboard - you rout them perpendicular to the crack - the green lines in the diagram

Merrily said:
The routing has to be big enough to slide rebar in to the blade. Also widen the crack so it will take more epoxy. Then slide in the rebar (with epoxy on it) perpendicular to the crack. Then epoxy, dry, and smooth that whole side. Flip it over and only widen the crack on the other side, epoxy, and smooth it. Is this a fair summation?
Click to expand...

Yup. Easy as pie

As I said, that's how I would do it - Might want to see what Gouv/and or Vanguard has to say
 
So the rebar is parallel to the crack--it's the blue lines? How does that do any good? I'm really confused. Sorry for being dense.
 
No, the rebar is perpendicular to the crack - see the drawing - the green lines represent where the routing for the rebar would go...

Between the blue lines is the area I would rout out to seal up the crack - it was hard to draw those , but it really doesn't need to be more then 1" to 2" wide, with the crack in the middle of it... Just trying to get lots of surface area for the epoxy bond.
 
Quoting a sailor buddy, "Available stuff in my garage rules my methods of repair."

Many sailkors have West system epoxy and some fiberglass mat.

If you don't have a disc sander you probably have a power drill and for this projet you can use a crappy disc on a power drill.

The patch has to have some strength. The strength must be transferred to the board ( The repair has to be firmly attached.

West sticks well to the laser blade.

Glass gives stength.

Use a sander and make a v shaped pocket for the repair.( It will be a really wide v)

The bottom of the v will be the center of the crack.

The outside edges of the v will be about two inches from the crack or we could call it a 4 inch wide v. (10cm)
The depth of the v at the crack should be about 1/3 inch or a centimeter for those of you in sensible countries.

Paint the yellow structural foam with the epoxy and then lay on layers of glass until the v is filled.

sand the eposy and glass until it is level with the rest of the blade.

If necessary use more West to fill voids and etc.

paint the blade.

go sailing

The blade will actually be stronger in that particular area than it was originally.

Quit doing jumping jacks on the board!!!
 
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