Deck beam cracked on a Chesapeake 18, how to repair?

Builder's Forum
1

I recently purchased a roughly 9 year old Chesapeake 18, which unfortunately has a pretty large crack in the deck beam.  While some bug thought it was a great place for a cocoon, I think I should repair it before going off-shore farther than I can swim! 

At first I thought I could just grab a clamp and some glue, and have it fixed in no time. Like I said, I bought the boat, I didn't build the boat, I'm definitely a beginner!  Now I realize that I would need a clamp with a 12+ inch throat to even reach the crack given its distance from the cockpit. I have not found such a clamp for sale for less than $200+ which is definitely more than I want to spend.  I'm wondering if I could improvise in essence some big chop-sticks which I tighten from the cockpit using a more modest clamp.  Has anyone done something like that?  Any other suggestions on how to pull the crack tight again?

Should I pull the crack tight before I apply glue, or apply glue and then pull the crack tight?  There are some nails/screws involved, and I'm a little worried if I pull the crack tight without glue, I'll have difficulty re-openning the crack enought to apply the glue.  However, if I apply the glue first, I'm worried that I will fail to pull the crack tight.

I don't even know what glue to use.  Should I order epoxy (is it even safe to ship epoxy during freezing weather?), or can I just buy something at the local big-box store that would work as well?

Instead of pulling the crack tight, would I be better off just filling the crack with something like an epoxy sawdust mix?

I'll try to include a low-res picture in this post.  A higher resolution version is at http://picasaweb.google.com/lh/photo/gMdS1RZUJBOOLFfB5ZwJvw?feat=directlink

thanks,

Bill

deck beam crack

2

Bill,

You might be able to wedge a stick from the floor of the cockpit up to the beam, pushing it together... use some rubber beneath to prevent slippage.  That'd be much more substantial than any clamp you could improvise (I think).

I'd definitely cover the inside of the beam with thickened epoxy (use cab-o-sil vice wood flour, will give you more strength), put the "glue" in prior to closing up the opening with the stick-clamp... that thickened epoxy will fill any gaps better than anything else you can come up with.  Then I'd let it cure for two or three days, just to make sure it's nice and "dry" before removing the stick/brace. 

It's an awkward place to have to repair; maybe someone else will have a better suggestion.  I'm a first-time builder of a 17LT, but have lots of experience gluing cracks in furniture and the like.

Good luck,

Larry

3

Why not drill a hole or 2 thru the deck and beam, squeeze some epoxy in there and bolt it together? Then unscrew the bolt and fill the hole after it has set up.

4

dthaler,

That's a great idea... better than my idea of a wedge/stick!  A bolt offers all the bennies of compression (lots of compression) without the hassels of the stick slipping. 

Is there a way to keep the epoxy from sticking to the bolt?  So you can remove it easily afterwards?

Good luck, Bill, let us know what you do,

Larry

5

Being a newbie to this epoxy business, I’m not really sure. Wax maybe? Or if you used some nice stainless steel or brass bolts and drill your holes in a nice  pattern you could leave them there.

6

Wax will work on the bolts. Put clear packing tape on the deck and drill thru it. That way when you put the bolts thru if there's any epoxy seeping through the hole it wont stick to the deck.

George K

7

My main resistance to the bolt idea is that it leaves a scar in the bright finish deck.  I'm also a bit worried about the bolts getting stuck and staying there forever.  However, I really like the idea that it is cheap with a high probability of working.

It occurs to me that there are two ways that I could use bolts.

Option 1:  Drill through both halves of the cracked beam and up through the deck.  Then stick each bolt through a drilled hole with big washers on both ends, and crank it down.  I would need to wrap the washers in packing tape, and put (melted?) wax on the bolts so they could be removed later, or use stainless steel or brass bolts and plan to leave the bolts there forever.

Option 2: Get two cross pieces of wood or metal.  Drill through only the deck in front of and behind the deck beam.   Run the bolts through the cross pieces, and crank it down so that the cross pieces pull the beam together.  If I put packing tape on both sides of the deck and on the cross pieces I would probably be reasonably safe from entombing my bolts forever.  I would probably need more than one pair of cross pieces with this approach, which unfortunately doubles the number of holes in the deck, but avoids putting any holes in the beam.  My guess is a beam without holes in it would be stronger than a beam with holes that I attempt to fill with an epoxy and cab-o-sil vice wood flour mixture.

Unfortunately, both options do still leave bolt holes in the otherwise gorgeous deck. I'm guessing the repair would be to tape the underside of the deck, and fill each hole with an epoxy and cab-o-sil vice wood flour mixture.  How visible would that be?  Since this would be my first time ever using an epoxy and flour mixture, I fear the results would not be very pretty!

Can anyone think of some useful hardware that could be mounted on or near the port end of the deck beam to hide the holes?

Does everyone agree that I should order some epoxy and cab-o-sil vice wood flour to make the beam repair?  Regardless of how I ultimately "clamp" the beam?

8

I think that the idea of running a bolt through the deck beam is a decent idea, but you may be able to make a clamp long enough to reach the deck beam. Either way you're going to put some compression on the deck. The suggestion of wedging something inside the cockpit seems good enough as well, but I'd worry about the pressure on the hull. That said, I have a Chesapeake and the hull seems to be indestructible. Fun problem. I would try to build a clamp. You could probably do it with stuff that you already have. I was thinking a pair of 2 x 4's something to use as a fulcrum, and a good rope that you could use to tighten the "clamp". If you drill through the 2 x 4's foward of the fulcrum, you could run the rope through the pieces and tighten it by twisting the rope... Like a tournequit (kind of like the stiches in stich and glue). It's weird, but I think it could work. I would definately put something down to protect the deck (piece of rubber or a towell). 

If you were to go with the method of drilling through the deck, you could just heat up the bolt enough to loosen the epoxy around it, then pull the bolt. I'm not sure the best way to go about heating the bolt, but I'm sure it could be done. I'd be leary of wax only because then you'd have to deal with it when you want to fill the hole. I've never tried that though so I'm just guessing, maybe it doesn't matter at all. I'd go with heat. Good luck. 

9

There may be a simpler way to repair the split. Provided the deck beam can be pulled back together, either with a prop or by hand, a screw run at an angle through the bottom side of the deck beam up into the sheer clamp should hold the beam together while a new slathering of silica thickened epoxy sets. You'll have no holes in the deck to repair and the epoxy will fill any remaining gap. The most difficulty you'll have is the preparation. What I would do is cut off the protruding screws with a hacksaw blade and either saw or rasp any rough places from tearout. This should allow the beam to fit back together easier. I'd also take a doubled hacksaw blade (two taped together) and saw up the glue joint through the narrow end of the split until I reached a point beyond any damage. When you squeeze the deck beam back together, you dont want the pressure of screwing the beam back into place and squeezing the thickened epoxy causing the split to lengthen. The small gap provided by the saw cut should allow the epoxy to fill in the gap and squeeze out - just apply slow even pressure on the beam until the split closes completely. If predrilled, a few screws just long enough to hold the beam together can be run in from the underside as you go along, starting at the narrow end of the split.

Just looking at the picture makes me think the lamination may have split due to being glue starved. If this is the case you may want to look over all glue joints and laminations periodically, maybe a couple of times a season, especially after hard use, to make sure nothing else shows up. From my experience most people overglue joints and laminations so you probably wont ever see another delamination. But it wont hurt to look things over every now and then.

 Good luck with the repair. George W.

10

another suggestion from the mechanic…how about a scissor jack or 2 with a plank under and on top of it?

11

I've been looking at the pic again and there might be another way to fix it without holes thru the deck. (Even those aren't a big deal if you get creative with wood veneers) It looks like one side is still epoxied together. You might try a line of wood screws from the underside of the beam to pull it together. Start close to the break and countersink a screw thru the outer two layers. Use a screw just long enough to get a good bite into the upper beam, which looks like it's still attached to the deck, but not go thru the deck. Move over a couple of inches and put another screw in. Repeat the process till you've pulled the whole beam together. If you use thickened epoxy (with cab-o-sil) you'll have plenty of time to work. You might use the internal prop idea to take some of the tension off the beam and make it easier to screw together.

Just a thought but I'd personally give it a try!

George K

12

Any holes can be nicely plugged with wooden dowels. In fact, dowels can be used to peg the beam bits back together again and just left in. Cut them off close to the deck and sand them flush. They'll look nice against the okoume.

Laszlo

 

13

George W. wrote:

I'd also take a doubled hacksaw blade (two taped together) and saw up the glue joint through the narrow end of the split until I reached a point beyond any damage. When you squeeze the deck beam back together, you dont want the pressure of screwing the beam back into place and squeezing the thickened epoxy causing the split to lengthen. The small gap provided by the saw cut should allow the epoxy to fill in the gap and squeeze out - just apply slow even pressure on the beam until the split closes completely.

 I'm not sure I understand this instruction.  Are you saying to use a saw to extend the crack a little farther?

-Bill

14

Yes, that's what I'd recommend, that is, short of removing the entire bottom half of the beam. Cutting a slot through to an undamaged part of the joint will allow you to ensure that the entire gap gets filled with epoxy, eliminating the weak spot that would otherwise remain. You simply cannot get epoxy deep into a hairline crack. I would dry fit the repair, predrilling the screw hole into the sheer clamp and any other screw holes needed to pull the beam back together (watch your hole depth and screw length so you don't go through the deck), then open it back up to glue it with thickened epoxy. The epoxy will fill any hole or gap left after cutting the old protruding nails or screws or  from where you cleaned up the old tear out. You can remove the screws used to clamp the beam back together after the epoxy has grabbed the joint well, but not cured. I'd leave the screw you drove into the sheer clamp. Silicon bronze is best for any screw left in place. You can fill the holes anytime after the screws are out.

You mentioned that you're a beginner. If you haven't read the tips on this website, please do. Make sure you use plastic to cover any area where epoxy can drip, because it will. Wear gloves. You may find it easier to work on the repair with the kayak on it's side at bench height or inverted on sawhorses high enough that you can sit on a bucket underneath it.

I'm sure there are a number of folks that would tell you that what I recommend is overkill, but then again it's what I'd do for any boat of mine. George W

15

Take heed of George W's comment about glue starvation.  If you use epoxy (which is what I would do), don't "crank down" on any bolt or other clamping mechanism so much that you starve the joint by forcing the epoxy out.  Better to use light pressure -- enough to expel the excess epoxy, but light enough that sufficient epoxy is left to cure into a strong bond.  And don't worry overmuch about small gaps, as thickened (but not thick) epoxy is great at filling them.

For that matter, I also like his idea of using silicon bronze screws to hold the wood in place while the epoxy cures.  Measure carefully, and you won't need to penetrate the deck, either.  Silcon bronze screws are the best choice for a marine application, and the metal is soft enough to readily file away any part of the screws which protrude, after the epoxy cures.  You can get silicon bronze screws at any marine supply source (e.g., West Marine). 

16

I’ve begun work, and have a new perspective on what is going on.

The deck beam is a lamination of three pieces of wood.  Along the port side the beam’s upper lamination has failed leaving a significant crack. Two screws come in through the sheer clamp, and seem to have bisected that upper lamination nearly perfectly. The bottom part of three ring nails coming down from the deck were also visible in the crack.

My first goal based on the forum’s advice was to clean out the crack and cut off the ring nails coming down from the deck.  My hacksaw would not fit, but a keyhole saw with a metal blade removed the ends of the nails quickly. 

I then discovered that the bottom two laminations of the deck beam would still not bend back up because it was too long to pass the shear clamp. The problem was a drip edge of what I am guessing is 9 year old epoxy along both the end of the deck beam, and the edge of the shear clamp. Removing that proved much more challenging because of the difficult access. Ultimately a coarse file, and some small sharp chisels took both the end of the deck beam and the edge of the shear clamp down to bare wood.  Now when I press up, the end of the beam clears the sheer clamp.  Though it takes alot of pressure for me to bend those bottom two laminations, and I am not strong enough to bend it far enough for an actual test fit.  That is where I stopped for the night.

Until today, I thought the deck beam failed under use, and there was a significant glue free section in the crack where it appears the wood failed, not the epoxy. However, the presence of those drip edges makes me think the failure may have occured earlier during construction.  Those bottom two laminations certainly prefer their current location, and do not want to bend to rejoin the upper lamination!

Working in that cramped space, I’ve concluded that I will not be using screws from the inside. The problem is that I do not own a drill small enough to pre-drill for the screws!

However George’s comment:
You may find it easier to work on the repair with the kayak on it’s side at bench height or inverted on sawhorses high enough that you can sit on a bucket underneath it.
Has given me another idea.  If I invert the kayak, I could use some weight lifting plates instead of clamps to press the laminations together.

So the next thing I need to do is order some epoxy and cab-o-sil.  Any advice on how much or which kind?  What is the shelf life on this stuff?

While I’m waiting for the epoxy to arrive, I need to start building some supports so that I can work from underneath the boat, and load the inside of the boat with weights.

Assuming that my weights will be heavy enough to bend the two laminations back into place during a test fit, admittedly a rather large assumption, here is my current thinking.  Any suggestions for better approaches, or cautions are welcome.

I think I will leave the two screws through the sheer clamp alone, if the test fit permits, since they are just where they should be.  While I was sawing away at the ring nails, I was thinking about George’s advice:
I’d also take a doubled hacksaw blade (two taped together) and saw up the glue joint through the narrow end of the split until I reached a point beyond any damage.
I actually think that would be relatively difficult to do.  Once I have the boat inverted, I will have gravity on my side at the narrow end.  I’m wondering if I could only thicken some of my batch of epoxy.  Then I would use a needle free syringe to spray/inject the unthickened epoxy at the narrow end, and spread only the thickened epoxy at the wide end of the crack. Is that likely to work, or should I stick with George’s advice to expand the crack with a saw?

Thanks for all the advice so far, keep it coming!
-Bill

17

Bill,

If I was fixing up a 9year old boat with obvious damage, I'd want at least a quart of resin and a pint of hardener on hand. Go with the slow hardener, it'll give you time to work, something you'll be glad of in the enclosed space. Once you've got it the way you like it, you can warm the area with a light bulb to speed up the cure.

For fixing the beam, just thicken the epoxy with woodflour. Something between ketchup and peanut butter consistency will work fine.You don't need cab-o-sil for this.

Yous shouldn't need anywhere near the whole quart for the beam, but I'll bet the old boat could use some sanding and refinishing to fill some scratches.

Have fun,

Laszlo

 

18

Well I just ordered the MAS #4 Economy Kit, so I should have way more than enough epoxy!  Between this order and my previous spray skirt and manual order, CLC now has more of my money than the guy who sold me the boat!

The MAS #4 kit comes with both woodflour and cab-o-sil.  Any reason to prefer one over the other for my deck beam repair?

Any advice on the saw the crack versus use some unthickened epoxy ideas?  Until the CLC order arrives, all I can do is build some kayak support racks, and worry about the repair.  :-)

-Bill

 

 

19

When you build your racks, include straps that will conform to the shapes of the fore and aft decks and make sure the stand that will go under the deck beam won't split apart at the bottom when you add weights to force the deck beam back together.  The strap and its anchor points need to be strong enough to support the weight you'll need.  Most of the building stands we make are sturdy and endure a lot of abuse, verbal and physical, but we don't want stuff to sproing apart with your head inside the upturned hull.

Good luck

20

Resin mixed and applied!


I ordered the epoxy, and while waiting for that to arrive I built my stand.  I grossly over-built the stand to hold the boat up at my shoulder height.  I'm pretty sure the stand I built could hold a plastic tandem kayak including paddlers!  My wife says the stand looks like a bunk bed.


Once I had the kayak upside down on the rack and a shop light inside (Tip: A fluorescent light is much more comfortable!) I started trying out ways to squeeze the bent beam.  The first thing I tried was an 8 inch mouth, 4 inch throat C clamp and some of the 2x4 scraps left over from my rack construction combined to look like a huge set of tweezers, and a scrap or mini-cell foam to protect the deck.  This worked so amazingly well, that I did not even try any other choices.


The next thing I did was use a thick saw and expand the crack until I was not certain if I was past the end of the crack, or cracking the wood some more with my sawing.  Doing this was pretty easy now that the boat was upside down at shoulder-height.  It would have been much more difficult with the boat right side up on the floor.


After vacuuming out the sawdust, I tried to put clear packing tape on both sides of the beam to catch any drips.  Unfortunately, the tape did not stick very well, so I am not optimistic this step was as useful as I expected it to be.
I then browsed the forum and Tips section of CLC’s site to refresh my memory on using epoxy.  I was also looking for how to mix resin and hardener by weight instead of by volume.  I’m pretty sure I saw such a post somewhere on the site in the past, but I was not able to find it again.


After getting into all my protective gear, I mixed up the resin.  I ultimately used a pair of two ounce syringes to measure one ounce or resin, and a half ounce of slow hardener.  I believe that I grossly over bought when I purchased the #4 economy pack!  The economy pack did come with pumps, but I was worried about priming them, I didn’t know how much they would dispense per pump, and I was worried about storing the pumps in a dirty state after this tiny job.


After stirring for about 3 minutes I filled a small syringe with epoxy, and set it aside.  Then I started adding Cell-O-Fill one teaspoon at a time to my mixture.  I had expected to receive Cab-O-Sil with my #4 economy pack, but I used what CLC sent.  After mixing a few teaspoons into the epoxy, I started to think it would be easier to work with if it wasn’t so transparent, so I added some Wood Flour.  I then started alternating Cell-O-Fill and Wood Flour until I had something like a runny jam mixture.  I tried to suck that up into the syringe I bought from CLC, but it was too thick to do that easily, so I filled the syringe from the large end.  My main difficulty during this time was getting resin and later epoxy all over my hands and tools.  I used a bunch of paper towels during this stage.


I then went to the boat.  The first thing I did was spray the fully liquid syringe of epoxy as close to the narrow end of the crack as I could insert the tip.  This epoxy did appear to run down hill farther into the thinnest portion of the crack.  Then I sprayed the thickened mixture from the other syringe further up the crack.  My main difficulty during this time was that my safety glasses were fogging up pretty badly.   I ended up refilling the syringe a number of times with the thickened epoxy, and pretty liberally filled the crack.  I also “painted” a little of the thickened epoxy mixture on the bare wood that I exposed shaving the end of the beam a few weeks ago.  I would have painted with plain epoxy if I had thought of it in time.


Then, after wiping my hands yet again with paper towels,  (Yes I was wearing nice gloves, but I did not want to leave epoxy fingerprints everywhere) I picked up the pieces of my wooden “tweezers” to clamp the bean.  The only difference between now and my dry run was the 2x4 which would be inside the kayak was now wrapped in plastic sheeting.  Naturally that changed things.  Where before friction had easily held the board in place, now it was slippery!  That gave me a minute or two of concern. Thankfully, once the C clamp started applying some pressure, the wrapped 2x4 was willing to stay in place.  It squeezed out a lot of my mixture, but based on my dry run tests, there should still be a fair amount of epoxy in the joint.  I cleaned up the excess as best I could with foggy safety glasses and the clamp in the way.  However, I definitely left a bit of a mess in there.  Fortunately it shouldn’t be very noticeable, since it is hidden inside the boat.


Questions:


How long should I wait before removing my clamp?  (The boat is in the basement, at 65-70 degrees).


How long should I wait before trying to clean the excess epoxy in the boat?  Any suggestions on how to clean it up?


Should I have pre-coated the bare wood in the crack with plain epoxy before using the thickened mixture?

Thanks,
Bill