Garboard Rabbit Braces

[wndsnd]

Hello All,

For lack of the correct name, I will call these braces or supports inside the garboard to back up the rabbit, there are also cross braces that do not show in the photo. This is the pine on oak 16' Town Class sailboat I am trying to save. My question: is there any difference on how I screw these braces in? I am using silicone bronze screws #10 and wonder if there is a reason to screw them in from the inside or outside. It would be easier for me to screw them in from the inside through the brace and into the planks. However I wonder if there is a reason to screw them in from the outside, through the plank and into the brace? These are not the oak frames, but the reinforcing braces that are everywhere inside. Some cross braces support a 1" by 1/8" oak batten that runs side to side.

http://www.imagestation.com/picture/sraid148/pc2c09d2e7bfacd7df74bccaaa64e3fc5/f611a7d7.jpg

From the picture you can see one old and one new brace. I am cleaning under and plan to epoxy as well.

I would appreciate any comments from the more knowledgeable than I.
smile.gif

[wndsnd]

Ok, So they are rabbets not rabbits! :D

[Tom Robb]

I'm not the least clear what these "braces" are that you're talking about. Do you have any good books on wooden boat construction? Perhaps a thorough reading would help you get the discription clearer.
The photo looks like some sort of batten seam construction - conceptually rather like board & batten siding on a barn. (I thought Townies were lapstrake?)
What are the fasteners sticking up thru the top of the broad strake?
Anyway, I believe that you'd do well to fasten the planks from the outside in.

[ 12-01-2004, 10:56 AM: Message edited by: Tom Robb ]

[wndsnd]

Hi Tom,

The Townie is indeed lapstrake. The picture you are looking at is from the boat actually being inverted and taken from underneath. The fasteners are new as I have replanked about 90 % of the boat. I used silicone bronze screws with nuts. They have to be trimmed and cleaned on the inside. I did do the fastening from the outside in. What I am refering to is the bracing on the bottom. The bottom is flat, and starting at the inside of the rabbet at the garboard there are braces. some run bow to stearn, and sum run port to starboard. the cross braces actually support the oak strips.
Does this help clarify it any better?

[maa. melee]

Lets see now, as you said, you are using some kind of bolt or screw with a nut on the end? Thats the first time I head something like that used to rivet clincker! I guess that brace is almost like a structural batten on the garboard seam? Anyways, I have a few comments. My first suggestion is to look up the history of the boat and find out how they were attached originally or how the design/plans specified these fasteners. Secondly, if this can't be done, push the screw in from the outside so you can achieve a flush surface on the outside. In aircraft, the bolts are always DROPPED in so, should the nut fail or get sheered off, the screw will still be intact and not fall thru the hole due to gravity. Why not use clout nails or chisel point nails and clench them over into the wood? Or better yet, copper or bronze wire rivets so you have the same surface on either side? Hope this helps.

Melee

[landlocked sailor]

I believe nuts & bolts were used to fasten the laps originally on Alden's Indian Class; at least they were on an example I saw in Rhode Island a couple years ago. Rick

[Bob Smalser]

Sorry, but not knowing the design, this chump remains stumped.

http://www.imagestation.com/picture/sraid148/pc2c09d2e7bfacd7df74bccaaa64e3fc5/f611a7d7.jpg

I see a centerboard trunk with what looks to be a mast step in front of it....

...a flat, 3-board bottom with the CB trunk piercing the center board, either dory-built with cross cleats (one has been removed) or some sort of keelson out of three flat boards...

...and what looks like replaced lapstrake planking fastened with machine screws long enough they lead me to believe there was a seam batten behind them like the new one I see let into the dory-style sawn frames at the garboard or first strake-bottom or keel joint. But if there were seam battens above the first strake, they don't appear to have been let into the frames as the first one is.

[ 12-01-2004, 03:04 PM: Message edited by: Bob Smalser ]

[wndsnd]

Ok Bob,

Cross cleats sounds like a good term to me so lets go with that. There are many of them spaced every foot. you are right, it is a three plank bottom. The cleats are what I was trying to figure out on whether to screw from the inside or outside. There are screws in the old cleats that were driven from the outside, but they were not original. The boat was built with galvanized square nails and they were not set like a rivet with a washer. The original builders family is using bronze bolts with nuts, I think you can see them on the ribs that were reinforced approx 10 years ago with plywood. The seam battens are only used on the outside planks, to reinforce the rabbet at the garboard plank edge. The reason I used longer bolts is because I had to use but blocks here and there for the new planks and I needed the additional length for the backing but blocks. Since I had the fasteners already, It was easier for me to use, I am cutting them off and
cleaning them up. There are no other seam battens, other than at the garboard plank edge. I bet that they nailed from the outside of the rabbet into the batton. However on the cleats the evidence is they nailed them in from the inside. At a later date someone screwed down into them from the outside to reinforce. Since I am replacing all of the fasteners, cleats, and battens, I started thinking of if there were strength issues doing it one way over another. Since posting this thread, I have been inclined to think that screwing and epoxying from the inside is better. Why create penetrations to the outside of the bottom planks unless absolutely necessary.

[Bob Smalser]

Under no circumstances epoxy the cross cleats...they need room for seasonal movement and one of the bottom boards will likely crack at at a future drying out.

Simply bed them in a non-adhesive goo and screw them down from the inside. Screws and bedding compound offer the little bit of "give" that crossgrain gluing does not.

Butter shut any outside holes with thickened epoxy....but don't epoxy any other joints not originally epoxied without careful consideration....both from wood seasonal movement and an eye toward somebody else having to repair that boat some day.

Were it mine, and since I had all those long machine screws driven already....rather than cut them off I'd consider milling some thin seam battens to fit between the frames if all my fasteners looked like those in the pic....they'll distribute the fastener load at that thin plank edge a bit better. I'd also bed them in nonadhesive goo, and countersink for nut and washer so no metal projects.

[ 12-01-2004, 03:44 PM: Message edited by: Bob Smalser ]

[wndsnd]

Bob,

Thats great advice. I will not epoxy the cleats. I follow your thinking on the lap battens, however since I have already replanked one whole side of the boat the way it is shown, I'm not sure I can go back and batten over the fasteners now. Though it would give the reinforcement that would be great over the years. But that being said, the boat lasted 48 years with galvanized nails, and the fasteners did fail eventually, and more and more were inserted over the years to shore her up, until all the planks split along the fastening line. BTW, all the machine screws were counter sunk from the outside and plugged. The bottom planks I am going to use traditional cotton caulking and sealants. I would expect there would be more movement in the bottom planks than in the strakes. Thanks John

[Jack Heinlen]

Townies are built dory style, upside down over sawn frames. Because of the angle of the garboard to the flat bottom, amidships the edge of the bottom comes to a feather edge, hence the backing battens. They may be original, but they may also have been added later.

In fastening the cross cleats to the bottom, drive the screws from the outside in, from the soft wood into the hard. As to the battens, I'd glue them in, with some temporary fastenings, or maybe some weight, to hold them until the glue sets.

Traditionally, lap fastenings for these boats were clenched nails, usually copper but I've seen iron in older boats. Rivets also work. Machine screws have been used in lap construction, but not, typically, in dories. Dories, by their nature, are meant to be a quick build, and clench nails are the fastest. The screws will work fine, but after you get them set and trimmed, bugger the thread a little with a light tap of a small cold chisel, to keep the nuts from loosening. And don't forget washers!

My 2 cents.

P.S. BTW, it wouldn't suprise me if there weren't a rabbet to be found on this boat. The only places there might be are on the stem and perhaps the planking in the centerboard well. But dories are typically built with a two piece stem, and the planking on the centerboard well is probably splined rather than shiplapped. FWIW.

[ 12-02-2004, 11:31 AM: Message edited by: Jack Heinlen ]