Your #1 source for kayaking and canoeing information.               FREE Newsletter!
my Profile
 





Bicycle and Kayak along Island Shores
San Juan Islands
See Whales & Eagles
www.crystalseas.com/BikeKayak
 
Advice, Suggestions and General Help New Topic Printer Friendly Version

  Gunwale Seperation
  Posted by: dougd on Jan-27-13 6:40 AM (EST)
   Category: unassigned 

I noticed last Oct/Nov that my MR Courier's gunwales were starting to spread a little. I tightened all the screws and kept an eye on it but it kept on doing the same thing. What has me a little stumped by this is it is only from the seat to the front thwart and no where else. I just can't figure out why this is going on. Any thoughts?

http://picasaweb.google.com/115656493558573181332/GunwaleSeperation

It looks like I am going to have to take them off and probably fill the holes with glue and re-attach them.

dougd

 Great Products from the Buyers' Guide:

Hardshell Kayak Sail Rigs

Yakuzzi

Classic Freestanding Rack

Mid-Hull Carts

Table of Contents




Messages in this Topic

 

  if you already tried tightening them ...
  Posted by: pilotwingz on Jan-27-13 7:53 AM (EST)
-- Last Updated: Jan-27-13 9:36 PM EST --

..... and they won't draw up , then you're probably correct , the inner rail bores have gotten too soft .

Ain't any possibility someone's messin with ya is it ??



 
 
  screws don't just pull out .......
  Posted by: pilotwingz on Jan-27-13 10:15 PM (EST)
-- Last Updated: Jan-27-13 10:17 PM EST --

..... for no reason .

I doubt any differential expansion or contraction between the inner and outer could cause a screw to pull out .

Something that could cause a screw to pull out is expansion of the top edge of the hull "if" it could absorb water and freeze .

Not much of anything can hold back water expansion when it freezes . I once saw a 1" hollow ball filled w/water inside the center of a 4' solid iron ball . The iron ball was frozen and expansion of the water in that 1" area ... cracked the iron ball .

Not saying you did this but , an incorrect bore , too large for the screw to bite properly , is a reason a screw can pull out . Another is using a fine thread screw where a course thread should have been .

Of course the wood getting too soft from water and/or decay ...

If it were me , for now I'd just clamp it up and add more screws , one in the middle of each existing .

 
 
  Hmmmm
  Posted by: clarion on Jan-27-13 7:54 AM (EST)
I've seen that happen with a punky core not visible from the outside. But you just had it all apart not too long ago and would have known if the gunnels had soft spots. I'm sure you used the standard screws. When you tighten them, do they actually tighten?
 
 
  Tightened
  Posted by: dougd on Jan-27-13 8:12 AM (EST)
Brian, They appear to tighten and I used the same screws I've used on other boats. I also made these gunwales about a year ago and they seem solid and I've stored this canoe under cover. I guess I figure it out when I pull them apart! Just very puzzling!

dougd
 
 
  Try beeswax on the threads
  Posted by: Canuka on Jan-27-13 8:19 AM (EST)
If you feel like you haven't stripped the holes by overtightening and the screws really are tightening, try rubbing beeswax (the real stuff) on the screw threads and reinstall them. Beeswax works as a very good natural "Loctite".
 
 
  Happened to me
  Posted by: PJC on Jan-27-13 8:25 AM (EST)
with my Starship. I ended up replacing the gunwales. But I did keep putting it off, first switching to larger diameter screws of the same length, hardening the wood where they threaded with Zap (a "super glue"), adding a drop of epoxy in the screw hole and screwing in, finally going to longer screws and cutting the tips off... I bought myself a couple years with these stunts.
The gunwales got a little "snakey" toward the end. I think a multi-day drive that involved multiple wettings by rain and drying at expressway speeds brought that on, perhaps exacerbated by slightly over-tight straps.
Finally it sent me swimming when the gunwales loosened enough to allow the sides to flex enough to let one side of the sliding seat to fall off its rail while I was doing a bow pry. That did it - I regunnaled.

There's probably a gunwale replacement in your future too, but you can delay the inevitable for a while.
 
 
  Maybe drill new holes in different
  Posted by: rpg51 on Jan-27-13 8:32 AM (EST)
locations as temp fix?
 
 
  Now That's Funny!
  Posted by: dougd on Jan-27-13 8:34 AM (EST)
PJC, Wish I could have been there to see that failure! The thought of it made me chuckle pretty good! Thanks!

 
 
  Chuckles...
  Posted by: PJC on Jan-27-13 2:14 PM (EST)
Well, I laugh about it too - now. Even the day it happened. But let me tell you it was COLD. Air in the thirties and water maybe 35. I was wearing layers of polypro everything, but no wet or dry suit as we weren't even planning on paddling a mile out... there's a lesson in that. A couple friends and I decided it was right and proper to go out and do a little memorial lake paddle for Black Walter who had just passed away.
Now, until Black Walter scuttled me on the Edisto the year before it had been at least seven years since I'd taken an unplanned swim. I don't intentionally "push the envelope" as much as many here do and I certainly wasn't planning on doing it that day. But it got windy and I was prying to turn my bow into it when I noticed myself looking straight up and seeing only green lake water. Very cold green lake water. And then a canoe seat floating next to me on the surface. First thing the person who was nearest me in a kayak said was, "What are you doing down there?" Then "Can I help?" With what? Swimming is one of those things we have to do for ourselves... no?
Well, I just swam the mess to shore. (It wasn't far but it was a cliff and deep right up to the shore.) Throwing what little modesty I have aside, I stripped (standing on a snow patch that by that point didn't feel particularly cold), wrung then shook out all my clothes, put them back on, reassembled the boat, and paddled back to the landing. Not much of a narrative there.
I was shivering, of course, but not uncontrollably. Its true that synthetic stuff is pretty warm even when moist. Putting that initial unpleasant shock aside, the paddle back was nothing worse than what you would expect from being out on a windy cold day for five or six hours. (Though we'd been out far less than that.)

I still think Black Walter's spirit had a hand in it... the guy was a prankster to the end and, apparently, beyond.
 
 
  Engineering
  Posted by: CEWilson on Jan-27-13 9:35 AM (EST)
From memory:?

Mad River seems to have cut the wood rail rabbet on the outwale. Curtis did the same. So, the inwale can, over time, slowly deform under paddler weight, particularly near the front drop, particularly for kneeling paddlers.

Solutions include replacing the dowel drops with Curtis/Bell trusses to minimize seat swing and doubling up on screw placement, ie 3" spacing in the problematic area rather than 6".

Take th old screws out, clamp the rail where you want it, drill and countersink the new, then replace the old.

bon chance
 
 
  Reinstall
  Posted by: booztalkin on Jan-27-13 12:17 PM (EST)
It looks to me like the outwale is longer in that section than the inwale. So, screwing them down tighter is problematic. There's just too much length in the outwale.

How that could happen, I can't explain, except to comment on the wonder and power of wood. Assuming both pieces are the same type of wood, they still aren't the same, and wood expands and contracts, each piece a little differently. As I am typing this, I'm thinking it doesn't make sense--how could any piece of furniture hang together if all the wood is always moving? How come everybody's wood gunwales don't do what yours are doing? And why only in the center part of the gunwales?

Okay, it doesn't make sense. Still, I'd try reinstalling that outwale. I think that's the same thing CEW is suggesting, but his rationale is probably better than mine. What I'd do is take out all the screws except a few in the middle of the boat. Then I'd tightly clamp the middle and refix the screws. As you move out from the center of the boat, I'd evaluate the need to redrill the screwholes. I sure would want to avoid that, but I think the holes will be a little mismatched, and new holes mean doing something with the old holes, making a lot of work. If you've got the stock around, it might be easier to just replace the whole outwale.

I'm just saying, unless the wood movement is a seasnonal thing, and the problem resolves itself when summer rolls around, there's too much gunwale along that outside edge of the boat. There's no way to shorten it, and you will be fighting a tough battle to try to get the extra material to go away by tightening the screws.

What's Conk say? To me, wood movement is a mystery. If anybody understands it, Conk will.

~~Chip

 
 
  A variation on this idea
  Posted by: guideboatguy on Jan-27-13 2:40 PM (EST)
-- Last Updated: Jan-27-13 3:03 PM EST --

I like the idea of the outwale being too long, but I think it's also possible that it's the inwale which is too long. Which one is too long depends on the actual stress that's going on. Is the gunwale being forced into a sharper curve than what's natural for it? In that case, the inwale is too long. Is the gunwale "trying" to assume a sharper curve than what's actually there? In that case, the outwale is too long. Either way, the screw connections toward each end, away from the separated section are supplying most of the stress, and you probably have to re-drill screw holes that are well outside of that separated section, but only while the gunwale is clamped AND properly curved. You probably understand the reason perfectly well.

Anyway, just to illustrate the idea of a too-long inwale, hold two sheets of paper together, flat, and edge to edge, then bend both of them into a continuous, sharp curve but without allowing any "slippage" at the ends. You'll see gaps open up between them along the curve where the inner sheet buckles due to being too long, but those gaps will will disappear if you let the necessary slippage between sheets occur, effectively shortening the sheet on the inside of the curve. I've never assembled gunwales "from scratch" (with new, undrilled pieces), but to me it makes sense that it should be done starting from the center and working outward toward the ends, while maintaining the proper curvature as new holes are drilled and screws installed. I also think it would be best to do this progressively the same on both sides of the boat, rather than doing one side first (wouldn't it be difficult to duplicate the same amount of curve on both sides if one side were done first?).

If the inwale is too long, maybe the inner piece tends to stay wetter than the outwale. Or maybe the wood wasn't fully dry originally and the outer section has dried more. Or maybe the two sections just have different properties, as Chip suggests, and the inner section expands more than the outer when both of them get wet.

 
 
  Sorry
  Posted by: CEWilson on Jan-27-13 2:49 PM (EST)
-- Last Updated: Jan-30-13 10:37 AM EST --

Sorry this isn't from Conk...

Some builders, MRC an included major, clamp[ed] the rails to the hull without a spreader bar, then start at one end and bore, countersink and screw the rails together. Images were up for Vermont Canoe a while ago that seemed similar to older MRC images, but VtC uses spreaders, etc as per best current practice.

This straightens the hulls top edge curve from tip to center to tip. Installing seat[s] and thwarts spreads the center, putting the rails into tension. The rail screws at center are fine but they progressively lodge sideways in the quarters. Certainly, there is more wood than needed longitudinally on the inwale; less than desired on the outwale.

Quick fix, more screws around the seat where inwale sags, in part due to lack of inwale rabbet.

Perfect fix? Make a spreader bar to fit hull at widest part of top edge. Remove rails, buy new and cut to length. Bore and countersink both inwales on drill press. Install spreader bar, then blind countersink and install center screws. Progressively clamping one quarter at a time from center to stem, blind countersinking holes through hull and into outwale before installing SS screws.

Perfect requires several more hundred of dollars and hours than the Quick fix, say $300 and 3 hours in a production shop verse $5 and 30 minutes.

 
 
  And after the fix, install a nice foam
  Posted by: ezwater on Jan-27-13 3:14 PM (EST)
pedestal designed for sitting or kneeling.
 
 
  Thanks All
  Posted by: dougd on Jan-27-13 4:30 PM (EST)
-- Last Updated: Jan-27-13 4:33 PM EST --

Thanks for all the advice. Just so ya know, and it's on my blog, I did build these gunwales from wood I got from a local mill so the idea of not being totally dried makes sense and I had thought of that. I rebuilt this hull to the specs I found on MR so I don't think I am off on width, yeah, I have spread out a few other hulls. I have been hanging my seats from gunwales for years on different hulls but hell who knows maybe that has something to do with this if I'm reading your response correctly CE.

I did countersink for the screws and clamped it every which way before I sunk the screws and for a year they held just fine. What does some to mind and this goes back to the wood I bought is that I started storing this hull in my barn which heats up and cools down as it is not heated and in my pea brain maybe the wood, as Chip suggested I think, reacted somehow to this temperature variation.?

I don't think the wood has gone bad, punky or rotten. It's too new for that and been stored inside and I did make it a little thicker than conventional gunwales.

Regardless it looks like a session of taking the puzzle apart and rebuilding it again.

dougd

 
 
  The wood looks good
  Posted by: pblanc on Jan-27-13 6:30 PM (EST)
I don't see why you would need to get new outwales or inwales. The outwales do look a bit thick.

I would take the gunwales off and take a bit off the outwales by sanding down the inner surfaces filling all the screw holes with epoxy, not glue or putty. I would use G Flex which bonds extremely well to wood, but other epoxies would probably work as well. The epoxy filled holes will be about as strong as the original undrilled wood.

Remount the gunwales as Charlie suggests using a spreader bar to maintain the proper beam and starting at center. Use the existing holes in the inwales and drill new pilot holes through the hull and into the outwales. You might wind up enlarging the existing holes in the hull somewhat but so what? Might reduce the tendency for cold-cracking if you do.
 
 
  We use...
  Posted by: openboater on Jan-30-13 7:01 AM (EST)
...a spreader and drill from center out to ends (not starting at the end and drilling to center.
 
 
  It's almost as though you've done this
  Posted by: clarion on Jan-30-13 9:09 AM (EST)
... stuff for a while!
 

Google
 
Web Paddling.net


Follow us on:
Free Newsletter | About Us | Site Map | Advertising Info | Contact Us

Sweepstakes

©2014 Paddling.net Inc.