Centerboard is getting on my nerves

[BobbyFunn]

I took the centerboard off last spring and when i went to fair and paint it i found that there was water inside it. This water intrusion was no doubt the reason for the gelcoat blisters.

I drilled about 20 holes all the way through and let it sit in the florida sun for days, changing its orientation often. Eventually, it dried out enough that i didnt hear it swishing around anymore.

It was faired, the wing shape was improved and all remaining damage from use was repaired. The deep repairs were a combo of marinetex and the west system activity kit. The remaing pits were filled with a bondo product for very tiny pinholes. It came out really good and had fun working with the different products to get a feel for what works.

Since i used bondo i thought i would use some black automotive filler primer and then apply marine topcoat.

So far so good. I added about 5 layers of paint, sanded, then polished. The shell was perfect and upwind performance was much better than before.

Been sailing regularly since the repair and admit that we grind on the sandy bottom. The centerboard shows some battle scars on the bottom edge.

Well, last week in my excitement of a great sail and concerns of the new tow vehicle pulling up the ramp i did the unthinkable. I loaded the boat on the trailer with the centerboad down.

The sound.... Might as well been my shin.
The new suv got us out no prob and i was able to check out the damage. About 18 inches of paint scraped off the leading edge and one good ding. It's a leading edge so i knew i had to lay some new paint there.

I pulled the centerboard out and figured this would be easy. Nope. Every time i went to sand the paint edge it was still loose enough to flick off a piece. I started sanding the whole paint job off but got lazy and tried a chisel. It was so easy my son asked if he could try it. It was almost satisfying watching the chips explode off as he scraped 1 inch wide swaths of destruction from one end of board to another. Even after chiseling the underlying primer coat was flawless. It had a cool carbon fiber look to it. I figured paint failure was due to an incompatible primer so sanded that off. It was very easy and so now were back to a mix of factory gelcoat, west system, layup, marinetex, and bondo. The base is in really good condition, even the deep red bondo.

This time I'm going to gelcoat/flowcoat/hotcoat the whole thing like a surfboard.

As I'm washing with soap i turn the centerboard and i hear it. Water swishing inside. Sounds like 8 oz worth. Unbelievable.

So now im trying to drain it.

I think the water is coming in at the screw hole that locks the centerboard to the hinge pin. The pin is underwater the whole time the boat is off the trailer.

Trying to think of how to seal the hole for the screw so that i can undo the screw and centerboard for future repairs.

Here are some pictures. On one you can see the sanded topcoat, primer, the fairing. The circular sharpie marks where fairing compound was needed are still visible. At this point in time i was thinking a couple coats of paint and be done.

The bottom of the centerboad shows the notch for hinge pin. A screw goes through the protruding bit then into the core.

Just blast it with 4200 sealant next time?

 

[Will Gilmore]

Bobby, consider opening up the cavity so that after draining the water and drying out, you can fill with resin. If you are concerned about the CB weighing too much, fill it with closed cell spray foam. Take away the empty space for water to go. Then glass it over, level, prime and paint as you would.
I would stick with marine specific products, West System, TotalBoat, ... . I have little experience with the products. I used TotalBoat products on my cast iron CB and haven't had it back in the water yet.

- Will (Dragonfly)

 

[BobbyFunn]

I like the idea of not giving the leaked water a home.

Would you suggest skinning one side or could i get a way with just opening up the area around the hinge and foaming that area?

 

[Will Gilmore]

I couldn't really tell you, but my instinct is that you can put in one or two larger holes and fill it from there.
At least start out that way. Use a probe (finger), maybe a dental mirror (auto supply store) and see how it looks.
Someone with actual experience with your CB may know how hollow they really are. Acetone is also a thinner for epoxy, that might help get it into the farthest reaches of your CB. Again, I don't have experience with this exactly, so more research is called for.
That is just how I would do it.

- Will (Dragonfly)

 

[Crazy Dave Condon]

It is time for us to talk on this one from an experienced former sailboat dealer if you want to. Send a private message

 

[BobbyFunn]

It is time for us to talk on this one from an experienced former sailboat dealer if you want to. Send a private message

Thanks Dave. I dont want to have to sign some non disclosure agreement.

I took a router on the surface along the path of the locking screw and see the issue clearly and have a repair plan.

The screw threads to a solid resin substrate but about 1 inch of the screw penetrates into the foam core. I will correct this by reaming the foam sorrounding the screw hole and pouring resin to the full length of the screw plus a little more. Afterwards, ill foam the remaining void.

I used a router to slit my centerboards throat, it bled water like a pig so it is probably delaminated pretty bad in there.

Im going to fix the hinge screw, repair the cuts then get back to sailing. Its 13 years old. Not bad.

Im going to assume every 170 centerboard has this affliction due to the screw entering the foam.

Dave, just post so we can all learn.

 

[Will Gilmore]

Dave, just post so we can all learn.

I, for one, am always interested in hearing Dave's advice. Experts like Dave are part of the reason I stay with SBO.

- Will (Dragonfly)

 

[BILLNPR]

Bobby, your plan sounds like the correct procedure, particularly filling the screw hole with epoxy and redrilling.

 

[GBGraham]

I was told long ago by a pro that gel coat does not adhere to epoxy?

Bobby, your plan sounds like the correct procedure, particularly filling the screw hole with epoxy and redrilling.

ere to Epoxy

 

[Crazy Dave Condon]

When I have questions, I ask questions often on the phone as to procedure materials and what was done/encountered to determine quickly what is going on as a former dealer and investigator as too much time and discussion can be elongated. Then I report back. I ask folks to send me their contact information which is private and discarded afterwards which often is on my nickel. And costly with those overseas calls. I am not paid to do this but try to help fellow sailors. You have no ide as to how much time I spend helping out to include traveling which alone I commuted for example yesterday to travel out of state to help on a 260. In addition I told hunter how to make repairs. However if someone does not want me to talk with them that is fine but I also have the choice to move on to help others. I also have other things I need to do snywsy

 

[Will Gilmore]

snywsy

What is snywsy?

- Will (Dragonfly)

 

[BobbyFunn]

Its just a $800 part Dave, not worth tying up a valued resource such as yourself over a forum topic.

If you have seen tbis issue already then a generic response would be perfect.

I will pick up some marine filler for below the waterline tonight. It doesnt have to be high strength. I might also replace the ss screw with a ss threaded insert and ss machined bolt. The existing substrate wont be compromised this way and water leaks should stop. The bolts olny job is to prevent tbe centerboad from pulling off tbe hinge pin.

I should then be able to fair with the remaining west system filler, clean, sand, clean, then gel.

The swishing sound is gone now. All the water was between the foam and laminate. I wont be trying to fix that.

 

[BobbyFunn]

Last night the area of concern was enlarged and all the foam in tbe cut area was removed.

Id love to see a how its made episode on this. There appears to be a plastic shell encapsulating the foam, then frp layup, then gel. The lower section has a thin lead plate, but the area im working in didnt have lead.

There is only about 3/8 inch of the plastic shell for the hinge screw to grab then its right into the foam core.

I had some left over west system high density so was able to pack in some epoxy through the shell until it noodled out the original screw hole, then covered the foam core. Tonight i will ill the remaing area with more high density epoxy, replace the skin, then lay up some fairing.

I would like to nominate the inventor of the pool noodle for a nobel prize. Can i do that.

 

[BobbyFunn]

The hole has been completely filled with epoxy and then fared with microballoons. I patched up any chisel scratches and any new pin holes exposed by sanding.

Cleaned with dawn, acetone and then alcohol. This should resolve issues with gel over epoxy.

Today the gelcoat was brushed on the second side. Can see why gelcoat is despised for aftermarket surfacing. It doesnt level at all unless poured. Going to have fun disc sanding that smooth.

I tried to squeege the gelcoat like a surfboard, but it was way to thin. I pre measured the gelcoat based on the coverage rate and after pulling it around I still had 3/4 left, so i ended up just pouring it out then distributing it evenly toward the masked edges.

I brushed as gentle as I could but it has a stickyness that pulls a ridge up at the slightest touch. I've rolled and tipped before, this stuff is a menace. Smells nasty. It was 75 and windy so perfect for garage duty.

Noob tips...use a medicine syringe to measure hardener based on the milliliters of gelcoat. I read too many reviews of people counting drops and the gel never getting hard.

Convert all measurements to milliliters. Makes calculating cc's of hardener easy head math at 2% ratio.

Fill a measuring cup with water, pour into disposable container, make a mark, write hardener amount on line.

Water plants with water, dry container, then pour gel coat to that line, add specified resin using syringe. Pros usually have those cool sqeeze neasuring caps . I didnt have that.

After about an hour the coat was dry to touch. Tomorrow I'll start disk sanding the brush marks out.

 

[Crazy Dave Condon]

With gel coat, you have to use a higher temp
hardner which can be bought at the forum store or possibly another marine outlet.

Gelcoat will not dry in air. There is an additive that can be added that will put an outside coating to cut the air off for the gel coat to dry. There is a spray that you can apply also after the gel coat has been applied.

I would if using gel would spray but it would have to be thinned out. Forgot the name of the additive but acetone could be used but not the best choice. I always constantly wiped off the nozzle to prevent buildup at the nozzle.

Bondo is not recommended particularly below the water line. Any filling I would use a two part epoxy more of a easy mix to work with such as Water Tite.

After the repairs I would either apply white barrier coat which if bumpy I would have wet sanded smooth or simply sprayed a specific white Krylon plastic paint over the centerboard or rudder

Hope this helps

 

[BobbyFunn]

I rehabbed the rudder last summer with the krylon and automotive clear coat. Came out nice after buffing. The surface is delicate though. Im done with paints on the below the waterline appendages. Between grounding in sand, prop snacking, and getting tossed around at boat ramp there is an abnormal amount of wear and tear. Mostly from my stupidity and carelessness. Paint seems easy, but this time I'm replacing the factory finish. Gelcoat is easy to procure and repairs will be the same as the finish.

It would have been better to spray though.

I used a laminating gelcoat but poured in the wax so it would final cure. I layed it on thick in one coat.

Its already for sanding and then buffing. I need to be careful I dont get too aggressive

 

[BobbyFunn]

Well, got the brush strokes out, but took a lot of gelcoat with it. Some areas were showing through. I stopped short of a full burn through. Looked really good though.

I had one 4" high-density foam roller left over from painting the hull last year and used the last 200ml of gelcoat on the smooth surface.

That looked 100% better than brush. I can easily wet sand that to average out the orange peel to a minimum.

Noob tip: Brush gelcoat as a last resort. Dont even think about roll and tip, just roll.

 

[BobbyFunn]

Its back in the boat!

I rolled on 2 more coats after the brush and sanding. I really didnt want to buy a third pint of gelcoat so i was not able to touch up the last bit of orange peel with a squeegee.

I maxed out the sanding with 1000 grit wet sanding, automotive rubbing compound, then polish. The high spots are shiny, the leading edge is shiny, and the rest is very smooth, but with some orange peel.

In two years when i pull it again i will probably cover it with 2 part poly, and rehab dings with west system.

Noob tip
4" High density rollers eat up about 50ml of gelcoat. If you mix based on estimated coverage be sure to add some for the roller. Its really wasteful to paint or roll on small surface. If you cant stand orange peel or brush marks be prepared to spend buy 2-3 times as much gelcoat as instruction suggest.

I used hawkeye gelcoat on the first pour. It had a powerful resin smell. The instructions were very good. The can came with wax and mekp. It cured well witb 2% mekp, but was still gummy when sanding.

The remaining 2 rolled coats were hi-bond from a local hardware store. The resin smell was much less. This sanded very nicely to a fine dust when dry sanded. The instruction suggested less than 1% mekp, thought that was too low, and used almost 2% mekp. Cured nicely, but the roller got pretty warm.

Time to go sailing.

Thank you for your help and ideas everyone.

 

[JimInPB]

Thank you for posting about this project. It is probably a preview of things to come for me.