Cracked hull help!

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alick burt
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Cracked hull help!

Post by alick burt »

Hi Folks
I went paddling the River Dee in Wales last weekend with a friend in the front of my boat and to cut along story short we had a few bumps on some rocks that resulted in some damage. :crying
The worst bit is a rather large crack that seems to have split and pushed the planking out of alignment although the outer skin is remarkably still intact.The crack is about a foot long.
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The planks are out of level by a sixteenth at the most. :sad
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I was thinking I might glue the split and try and pop it/clamp it back into position before rubbing down the inside and patching with cloth and resin but my question is how do I clamp it to push it back into alignment? :thinking
It is too far in to get a clamp to though I have worked out that I may be able to do it with a station shaped piece or pieces of mdf shaped to suit.If anyone has any clever ideas on how to achieve this I would be grateful. :thinking
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The next problem is a similar crack that is the same but is still aligned ok.I am guessing it is just a matter of rubbing down and patching with cloth and resin but how do you end up with a level surface after you have added the patching material should I scrape a recess into the damaged area?
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Apart from that we caught the keelband on some rocks too but I think this will just need a bit of patching until I eventually replace the whole length at later date!
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Many Thanks
Alick
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Jim Dodd
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Re: Cracked hull help!

Post by Jim Dodd »

Hi Alick

I would clamp a piece of wood across the gunnels, and clamp another piece of wood to that, in a manner that would force the hull back into shape. Be sure to put plastic between the hull and the wedged wood.

The old saying is " If you can build them, you can fix them "

Good luck !

Jim
Keep your paddle wet and your seat dry!
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Cruiser
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Re: Cracked hull help!

Post by Cruiser »

Hi Alick,

Nice pics, they help so much to understand the issue

The misaligned crack looks to be under a bit of compression, maybe figure a way to put a lit outward pressure, to allow it to fall back into place. That shouldn't be too tricky to do, I also would really consider epoxy if you can get it realigned and sitting back in the proper position. I have never had much luck trying to force wood back together if it was under any kind of tension, so I think the first step is seeing if that compressive tension could be lessened to allow the wood to reseat.

Once you have the crack part repaired, the fiber glassing will be pretty straight forward.


Just my opinion.


Brian
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Re: Cracked hull help!

Post by Rabbit »

hi alick :)

i was thinking the same solution as jim to hold the lifted piece down. as cruiser said, there may be some tension. you may have to think about maybe removing the thwarts and seat frames if possible to give you a little flexibility. if you can expand the hull a hair it may make popping the lifted bit back into place easier. i found with the many cracks i had to deal with when i repaired my hull after the strong back got blown over, the edges of the crack is jagged through the thickness of the timber, and flexing it apart a little when putting it back together helped it click back into place. you may even find once you do this you may not have to clamp while the glue dries. i also found that rather than trying to use glue, seeping unthickend epoxy into the crack worked a treat. you could also use a ca glue to seep into the crack.

as far as patching goes. initially the edges of the patch will stick up a bit, but if you put a couple of coats of epoxy on, let it harden, then sand the edges to feather into the original epoxy, then put a final coat of epoxy on, the edges disappear and it becomes hard to tell where the patch is. i did a few patches on the outer hull to fix some flaws i wasn't happy with, and try as i might, i can't find where those patches are.

good luck with your repairs. :tu
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Jim Dodd
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Re: Cracked hull help!

Post by Jim Dodd »

There are soo many ways to skin a cat !

You could trace your old forms on cheap particle board , cut and trim so they fit under your gunnels, tape it. Since you have your old forms, it would be easy to cut a few to set the hull right. Then make your repairs.

Again Good luck, and please share your experience !

Jim
Keep your paddle wet and your seat dry!
alick burt
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Re: Cracked hull help!

Post by alick burt »

Thank you for all your replies guys
I hadn't thought of taking seats and thwarts off but that sounds like a great idea to give the hull more flexibility when I attempt to pop it back.
I will hopefully have a go at the first part of the operation tomorrow I was thinking of using my polyurethane glue for the split as I can pump it in and it goes off quick but I may go with epoxy instead for the opposite reason as its slow cure will give me more time to align the pieces!
Will post my solution or any further problems I encounter!
Many Thanks
Alick :tu
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Jim Dodd
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Re: Cracked hull help!

Post by Jim Dodd »

Go for the epoxy ! It will blend in color, and be the strongest, and longest lasting.

Jim
Keep your paddle wet and your seat dry!
alick burt
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Re: Cracked hull help!

Post by alick burt »

Here we go I started the repair this afternoon.
Yes Jim I went for the epoxy in the end and as you say it will be more invisible than the other options which won't be a bad thing.
I started by cutting out a piece of chipboard to approximately match one of my stations near to the crack.
The piece I had wasn't quite big enough so ended up adding a bit at the end but this gave me the option to wedge it apart slightly too.My idea was to clam this contraption to the gunwales not worrying about getting an exact fit as I was to put wedges in the gap only in the places where needed.I also took out the yoke to allow for a bit more flexing.
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I clamped the jig to the gunwales and began wedging the planking gently whilst my epoxy warmed on the stove.
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I wedged the end piece to see if the crack would open at all.
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At this stage I mixed my epoxy and put some in a syringe to squirt it in.There was no need for a needle on the syringe as the crack was open enough to just run the epoxy in.
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Despite my wedges the planking wasn't going level so I decided to apply some force with a hammer and block of wood tentatively tapping where it stood proud.
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Bit by bit the cracked plank went back into place and I added another pair of battens with bits of timber and wedges where required further along the crack.
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Once the planks were aligned I put a ratchet strap around the hull to bring it back together.
I put another batten on the other side.
Image and on the outside of the hull I put a wedge and a c clamp used in reverse with its handle pushing on the appropriate spot.
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Having done all this I wiped off any excess epoxy and left it to set.
Cheers
Alick
alick burt
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Re: Cracked hull help!

Post by alick burt »

Hi Folks
The next stage in this repair sequence was to scrape and sand the surfaces in preparation for cloth and resin.
I began with scraping.
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and next came sanding.I used an old tin to wrap my sandpaper around which worked quite well.
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I cut out some patches from offcuts of cloth I still have plenty of these left from previous boats!
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Next came wetting out and as I had plenty of resin from just one squirt on my pumps this was easily achieved with just one mix.I put it on by spreading with a squeegy after pouring it in a line along the patch and then after about forty five minutes I squeegied off the excess and left it for a couple of hours.
ImageThe only problem I noticed which I think will be minor is that at the edges of the patch some of the cloth edge was dragged out by the squeegy.
After 2 hours I gave them a fill coat.
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and then all was left to set overnight.
Next day I started sanding but noticed my paper was getting quite clogged so decided to leave the inside to set a bit longer and work on the outside.
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In addition to the cracks I had repaired on the inside I spotted another one at the other end that showed on the outside only.I began by scraping and sanding it.Then I sanded the rest of the hull in preparation for a fresh coat of varnish later.
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I repeated the process I had used on the inside starting with cutting out patches from cloth.
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The wet out was slightly trickier as the resin was more inclined to run on the convex surface but I left it to set longer before squeegying off and it was fine.
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A few hours later I had it filled and left it all to set.
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Cheers
Alick :wink
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Cruiser
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Re: Cracked hull help!

Post by Cruiser »

Nice job on that Alick ... I don't know if you did this or not, but after the first epoxy sets up ( and prior to second coat) you can use a scraper to flair the edges of the patch. Then a light sand with 120 paper makes the edge almost invisible when coat #2 goes on.


Brian
alick burt
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Re: Cracked hull help!

Post by alick burt »

Hi Brian
I didn't get a chance to scrape between coats as my resin was still too liquid(the cloth would have moved when I was at the fill coat stage) if I had worked it too hard at that point so maybe I will try that next time leaving it longer between coats in order to scrape and rub down between them.
Thanks for the tip though.
Cheers
Alick :applause
alick burt
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Re: Cracked hull help!

Post by alick burt »

Hi fopon a lks
I finally got some varnish on my repaired boat this week and hit upon a system that others may find useful.Instead of reaching for the usual oil based varnish that I use (flag)I decided to try a water based gloss outdoor varnish from rustins.
I found this easier to brush on as it is not quite as sticky.The brush is easier to clean.It has UV inhibitors in it so should be good and the big bonus it takes just four hours to dry between coats.
Using this getting two coats on is a day is easy but it does have one down side.
That is that it is not quite as glossy so doesn't give that mirror like gloss that you normally get.I hit on a solution that I am hoping will work and that is I put a final coat of my flag oil based varnish on top.
Here are some images of the final result.
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Does anyone else use waterbased varnish in this way?
Cheers :wink
Alick
Rabbit
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Re: Cracked hull help!

Post by Rabbit »

if you are mixing varnish types you had better be sure that the water based substrate has had enough time not just to dry, but to cure.

some water based varnishes can be less than high gloss. i seem to recall glen mentioning a water based spar varnish that finished with a high gloss. in my case i used a water based urethane and found that it got glossier with each coat. i spray rather than brush, and spraying resulted in drastically reduced dry times between coats. certainly safer to work with than the automotive urethane i would have used. your idea of just using the one coat of solvent based rather than all coats certainly saves your health, but be sure that one is a compatible substrate for the other or you may face delamination issues further down the track.
alick burt
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Re: Cracked hull help!

Post by alick burt »

Hi Rabbit
Yes,de-lamination and incompatibility are points I am aware of which is why I am experimenting on my own boat first that way I can see if there are any problems before using the system on the boats I sell.
Cheers :wink
Alick
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