Deck core

DAEDALUSCAN · **Joined:** 09 Dec 2007 21:03 **Posts:** 114

Has anyone replaced any of the deck core?

I have a couple of soft spots on the starboard deck, between the chainplates and the genoa track.

I will be addressing this soon, but want to buy some balsa core before I leave San Diego in a few days for Mexico.

Can anyone tell me how thick the balsa core is?

Any information would be much appreciated, Charlie

Tortuga's Lie · **Joined:** 27 Oct 2006 10:32 **Posts:** 827

How big of an area? Sometimes you can drill holes from underneath to let things dry out and inject epoxy into the holes after a period of time. This would save the deck and non-skid. If the aera is too large, cutting form top down is often the way to go.
I have not had to do this, so I can't tell you how thick the coring is exaclty, but I believe it is 5/8" although I have read somewhere that it is 3/4" Question

DAEDALUSCAN · **Joined:** 09 Dec 2007 21:03 **Posts:** 114

Its actually hard to say.

I was just going to cut out a section of the non skid from above, but I would really like to save it and I cannot think that it will be easy to refinish well.

So the present plan is to take the liner out of the pilot berth and cut out a section where it seems worst and replace from below. I would really like to replace with the same material, though I have thought about airex or even plywood. I will maybe just ring Tartan.

This is all complicated by the fact that this is my sons bunk, we live on the boat and I have no access to power (probably a good thing dustwise)!!!

ByronH · **Joined:** 27 Aug 2008 09:24 **Posts:** 40

Hi - Yes, I have replaced the core, but on the port side around the chain plates. I have also done it years ago on another boat. If you can get to the area from below, that is the best way to do it. I used a dremel tool to cut into the area. I have some photos I took during this process that I can send to you if you will give me your e-mail address. I did not replace the core with balsa, but a fiberglass honeycomb that would not break down in water. Off hand I don't recall what it is called, but I can look for it. It was quite a project. Good luck. Byron

sord · **Posted:** 07 Dec 2009 13:43

Why not post for all of us to see? Please

ByronH · **Joined:** 27 Aug 2008 09:24 **Posts:** 40

I would be happy to post photos, but don't know how. I have written a description of how to do this with photos, but don't know how to post it. If anyone has this ability, I would be happy to e-mail the description and photos to you and you can put in on this web. My e-mail address is lavieve@hotmail.com

Velera · **Joined:** 29 Dec 2006 09:38 **Posts:** 656

Did you folks actually find soggy core? My deck gives a little when you walk on it but drilling from the underside did not expose anything that looked like there had been water damage. Also, on my boat, the places where factory hardware were put through, were solid fiberglass.

ByronH · **Joined:** 27 Aug 2008 09:24 **Posts:** 40

If the "give" is uniform as you walk the deck, the integrity of the deck is most likely intact. If you notice more give than normal, that is the time to be suspicious, especially if it located near a through deck fitting. There are moisture meters that can be helpful if it is done by an expert. Another way is to tap it with a small hammer and listen to the sound. If there is a wet area, the sound will be different than other areas of the deck. My experience is that the sound in a contaminated area will sound somewhat dull and hollow.

Falco · **Joined:** 23 Dec 2007 23:08 **Posts:** 42

As my company builds sailboat and amphibious aircraft hulls using core, maybe I can be of assistance. As noted previously, just because the deck is "moving" doesn't mean the core is bad. This could be simple delamination (not enough resin was put on the two surfaces when they were being bonded together or not enough pressure was applied to get them to bond). To test if this is the case, tap on the surface with a light hammer or something similar. A high pitch sound implies that things are dry. Softer "thunks" happen when wet. If there is a lot of space that is delaminated you may even get more of a high-pitch drum sound and it will sound "dead." I have this in my foredeck and the deck squeeks when you step on it "just right" (to be fixed this winter).

In any event, if you want to see if it is really wet core, drill a hole. If you can do so from below, all the better as there is no potential for a future leak or noticeable repair. Wet and rotten core is quite self evident. Should that be the case, remove all of the rotten material and then some (from below if you can), grind the glass to ensure a good physical bond and then place into the space new core. The new version of balsa is treated with biocides (I believe cuprous oxide) to prevent future rot. The gaps between the cores (old and new) should be filled with putty (resin and Aerosil well mixed).
Glass over the core.

If doing this from the deck , try cutting the glass in a nice rectangle with a diamond wheel cutter in order to save the deck and the non-skid pattern. Cut in smooth areas as it will be easier to make the seam disappear later on. You can also mimic the non-skid by green waxing the deck, making a quick mold using gel coat and a few layers of chopped-strand mat. Then, you can make all of the deck you need and have it look the same as the original.

If all you have is delamination, drill one hole at the extreme of the void (e.g. the furthest point forward where you still here the thunk of a void) and then drill three or more holes at the aft extreme of the void. The holes should be the size of the nozzle of a mustard/ketchup squeeze bottle. Fill the bottle with catalyzed resin and squeeze as much resin into the forward hole as possible. When the resin starts coming out of one of the rear holes, put a piece of paper tape over it and keep squeezing in resin until all holes are "bleeding" and no air is coming out. Once done, place the heaviest weights you have (big bucket of water, extra group 27 batteries, etc,) on the area to ensure a bond. Use lots of weight....Use lots of weight! Did I mention using lots of weight? Just checking....

Good luck

Tartan37.com

Deck core

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