help fixing the gunwale to top of stanchion

[mic]

I've just bought the timber to replace the gunwale on my boat but am at a loss as to the best way to attach the gunwale to the top of the stanchion. The stanchion's are 3"x3" solid timber pieces poking out aproximatley 13" from the deck, here's a pic. http://www.imagestation.com/picture/sraid43/pa14440255ed7555b16dd7c3d5a581bb9/fce27900.jpg
The old owner just coach screwed the gunwale to the top of the stanchion into the end grain which is very poor, and has split some of the stanchions. Now i'm thinking of cutting some nice knees out of 10x2 off cuts that i can get for free, putting a knee on each side of the stanchion, bolting the knees through the stanchion and up into the gunwale. The problem is that they're not proper grown knees and no matter which way i face the grain either horrizontaly or verticaly i'm scared that the knee will crack over time. Any ideas on perhaps cutting the knees in two pieces and joining them in a toungue and groove type arrangement to aligne the grain parallel with the other timbers or any other ideas please. P.s. note gunwale material is 2" and there are 46 stanchions.

[Thad]

Not the best of course, but knees cut from straight grain stock should have the grain running diagonal across the angle.

[Gord May]

You could drill and insert dowels horizontally into the upright stanchions, providing a cross-grain bite for your cap-rail screws.

[Paul Scheuer]

That's a lot of knees. There must be some ultra-traditional way to do this. The only reference I have shows the rail notched over the frame tops and longitudinal rail clamps inside and out. The result is all cross grain fastenings, and an opportunity to enclose the frame tops.

I'm looking at a reprint of Charles Desmond's "Wooden Ship Building" from 1919, so there may be some later methods.

[mic]

Yeh i know Paul it's a sh#t load of knees and a sh#t load of bolts for that matter, if there was only a few to buy, i'd just buy grown ones.
I like Thad's idea of running the grain in a diagonal direction, but because the knees are only 5" down the stanchion and maybe 4" across the top i'm not sure that it will strong enough. The dowell idea seems ok but i don't want to do too much damage to the stanchions, surely there mast be other solutions. What about laminating some knees?

[Gary E]

If your requirement is to fasten the gunwale to the stanchion with as secure a connection as posible, I can think of 2 methods.

Version 1..
Have 46 angles cut from either stainless steel or galvanized, 2x2x 1/4 cut 2 inches long. Now visualize them as a L shaped clips, now on the lower surface drill a 13/32 dia hole centered in the bottom of the L, this hole will be for a bolt coming down from above. On the other surface drill 2 same size holes aprox 1/2" from each side and centered verticaly, these 2 holes will be used to fasten this angle clip to the stanchion. You may be able to use a 2x1 1/2x1/4, the 1 1/2 leg under the gunwale, the 2 in leg aginst the stanchion.

To install them, make a jig that sorta looks like a "C", with the bottom of the "C" located and clamped aginst the vertical stanchion, and the hole in the upper part of the "C" used to guide the drill. Measure and make it accurate, and it will go together eazy.

After the hole is drilled through the gunwale, the clip is then located aginst the stanchion and either lag screwed or bolted. Then the bolt from above is tightened up. Plugs can be used to plug the holes and hide the bolt holes in the gunwale.

Version 2...
Same idea but using a blocks of wood instead of angle clips.

Good luck
G

[ 01-24-2004, 05:37 PM: Message edited by: Gary E ]

[Paul Scheuer]

I just revisited the picture. You've already got a rail clamp and some sort of a plank outside. Why don't you want to attach the cap to them ? How was the structure originally put together ?

[mic]

Not sure what you mean by "the rail clamp",but the board your refering to is just a covering board aprox. 6x1 hiding the connection. I'm reluctant to screw any thing to this board because it has no structual bearing, besides its going to be replaced with a sexy varnished moulding, also as i mentioned earlier the old owner just coach screwed the gunwale to the top of the stanchion into the end grain. Here's an updated pic when i ripped the board off
http://www.imagestation.com/picture/sraid44/p64970dba637c5acbce995ce046a4b79e/fcdd9a4c.jpg

[Banjo]

Gday Mic,

I see your in Melb too! smile.gif
Not sure if this idea is good for your situation but I have done this before to make strong joints without the need to buy any metal screws, bolts or hardware. The only catch is it's a bit more work but worth the effort.
The pic I made up should be self explanatory, the diamaeter of the dowel would depend on the endgrain thickness of the material it is drilled into. The small wedges create a good mechanical connection backed up with a good strong waterproof glue the joint is better than any metal screw or bolt can reproduce.
http://users.bigpond.net.au/banjos-backyard/scan1.jpg

Banjo

[Paul Scheuer]

In the first picture, that longitudinal piece appears to be just under the cap.

The diagram that I'm looking from the old book is a section view of steam trawler with a 24 ft. beam. It may be a little heavier than what you have.

I don't think I can scan the diagram. If this word pictrure doesn't do it, I'll try a sketch.

He shows the bulwark stancheons 3' high, 5" at the top. He's got a longitudinal 3" by 5" oak "rail clamp" attached inside the stancheons, and a 4" by 6" piece that he doesn't name, notched for the stancheons and attached outside. All this is level with the top of the stancheons. The cap sits on top of all this, and is apparently attached at its edges to the inboard and outboard rails. The outer piece with 1" notching around the stancheons looks like it would keep everything square without knees.

He shows similar constructions for larger vessels using more massive pieces. At one point, he names the outer piece as a "top strake". At anoter point he shows the inboard piece as having the notches.

[Frank E. Price]

Check out Chapelle's book on American fishing schooners. He diagrams a couple of methods. The simplest was a spike toenailed through the cap and into the side of the stanchion at the head. The other shows a square spike with a flattened end with a hole in it. The spike was driven through the cap close alongside the stanchion and another smaller nail driven through the hole into the stanchion. He doesn't show any fastened straight down into the end grain. Stanchions were sometimes tenoned into the cap, sometimes not. This is from memory, don't have the book in front of me. With a boat like yours, mic, I highly recommend buying a copy. Lots of good stuff.

Frank

[mic]

Thanks guys, it's difficult is'nt it. Hey Banjo do you think your dowell system will be strong enough, i suppose some silicone bronze L/ brackets will do the trick but the price!

[JormaS]

In my Colin Archer it´s done like Frank explained, except that it´s not a spike but a stainless steel bar with threads and a nut sunk into the gunwale, then plugged of course. They sit on every third stanchion. Easy to take apart when needed.

[Banjo]

Originally posted by mic:
Thanks guys, it's difficult is'nt it. Hey Banjo do you think your dowell system will be strong enough, i suppose some silicone bronze L/ brackets will do the trick but the price!G'day Mic, not sure if it would be strong enough. It depends how big the diameter of the dowels can be. The problem here is that the bigger the dowel diameter the less material surrounding the bottom half of the dowel in the stanchion.

I just thought of another way, you could fix side pieces bolted either side of the stanchions that project the thickness of the capping peice above the stanchions and mortice them right through or else use stop mortices for a clean finish on top? This would be fiddley work getting it all lined up accuratly though smile.gif

Banjo..

[PeterSibley]

G'day Mic,
my two bobs worth is probably the same as Jorma Salomaa's.

I'd go down to my local bolt place and buy 43 100 or 125 x 8mm 316 ss bolts and nuts .Maybe less if they're expensive, but they shouldn't be, stainless has got pretty cheap. I'd bore in from the side of the stanchion with a 20mm spade bit, drill a counter sink into the top of the rail big enough to take a socket to fit the 8mm bolt head then run an 8mm or 5/16" bit down to the hole in the stanchion.( or you could drill the stanchion hole second )

Hold the nut in the stanchion hole with a pair of pliers or a ringspanner and wind it up.Plug the hole with a length of broom stick....20mm and the rail with a plug.Should make a nice tight quick job !

[whb]

Jst to take Jorma and Peter's idea a step further.

You can get circular cylinders that have been drilled sideways and the hole threaded for building take apart cabinetry. Then you just drill a circular hole the size of the cylinder into the side of the stanchion and another to meet it through the top of both pieces.

They are only 1/4" but if you put one in every stanchion they should be strong enough. The only thing is I don't know if you can get them in silicon bronze or other acceptable metal.

Here's a sample.

http://www.leevalley.com/hardware/page.asp?SID=&ccurrency=1&page=40445&category=3,40842,41269

Good Luck

Howard

[mic]

I think that drilling through the stanchion on an angle is obviously the best fix thanks Frank and Jorma,i can't believe it was so obvious. I'm trying not to use stainless steel though so silicone Bronze rod seems to be the go if i drill it through on an angle of aproximatly 45 degrees do you think i could bend the top a bit without weakening the rod so the bolt and nut sit flat and take up less space in the gunwale?

[PeterSibley]

Mic, if you don't want to use stainless, use copper rod. Totally traditional if thats a worry.... easy to thread( in small sizes) say 1/4" or 6mm, easy to bend the rod to any shape....much easier than bronze rod of any type.Buy a bit of 1/2" wide flat copper say 1/4 " thick and cut it up into 1/2 " sections, bore a hole in the centre ,3/16" and tap to 1/4"Whitworth.The result will be cheap totally non corroding bolts !
Bye the way I find those very thin angle grinder cutting discs ,about 1mm thick cut copper well.You can also form a head on the top end should you want to, instead of running two threads.

[mic]

Hi Pete, the only reason i don't want to use stainless fastners is for the fact that the ones i've pulled out have realy bad cases of crevice corrosion, for this application it's not so much strength that's required but more so longetivity.
i've noticed your thread on tapping copper bolts and it looks like the way i'm going to go, drill a 5/8 hole on an 45 degree angle through the stanchion and bend the copper rod a little so the gunwale can sit flush. I'm scared if i use Bronze rod it may weaken if i bend it 45 degrees, i've asked the question but nobody has given me an answer as yet.
I'm still wondering if i could weld two bolts together either copper or bronze at a 90 degree angle this would be the best but i'm not sure it would be strong enough and how well they will weld up. :confused:

[PeterSibley]

I wouldn't bother to weld it up.Just use the copper.It bends very easily and I'd say its going to be quite strong enough. What material were the original fastenings?