Rock me...

[Tar Devil]

I need some suggestions for the best way to build a stongback for a highly rockered, flat bottomed, double-ended dory.

I eagerly await the esteemed wisdom of my nautically inclined superiors!!

Later,

Phil

[mmd]

Hi, Phil. Below is a photo of the setup at The Dory Shop in Lunenburg. They have been continuously building traditional Banks dories for a bit over a hundred years so they have pretty much got it down right by now. The guy on the right in the blue jacket is Kim Smith, the owner of the shop. His son - the guy with his back to the camera working at the bench - does most of the dory work now and it takes him three days to build a fifteen-footer (length of bottom) from a stack of spruce to ready for paint. Poetry in motion.

http://www.imagestation.com/picture/sraid35/pf41799e331487e24ef31df70235e2250/fd2e0418.jpg

Notice the blocks on the floor - these are adjusted in height to control the amount of rocker in the botom, which is forced down on the blocks by spalls temporarily fastened to the overhead strongback. The moulds (these ones Kim built in about 1970, patterned on the previous moulds, which were patterened on the prev... you get the idea.) are then placed on the sprung bottom and the oak stem and transom fitted and braced in place. The planks are then served up, fitted, the gains planed and then fastened to the bottom & ends. The plank ends are allowed to run wild until planking is complete, then trimmed. After planking, frames sawn from natural crooks are fitted & fastened, inwales & thwart stringers installed, stem & stern knees fitted. Finally the gunwales & false stem are fitted, thwarts installed, the moulds are removed, and the boat is ready to go.

Simple, right? :rolleyes:

[ 10-11-2002, 12:33 PM: Message edited by: mmd ]

[Ian McColgin]

The ladder frame strong back shown by Gardiner will do it. If you think it might bend, upgrade the longitudinals to 2x6.

G'luck

[Tar Devil]

Thanks for the input, guys, but as usual I failed to provide relevant information...

The boat must be built upsidedown because my work area won't allow anything else, addditionally the sides/bottoms will be of ply and dimensions must be procured from dryfitting to the frame.

Ian, I'm assuming you mean the Gardner of dory fame? Shamefully, I don't own a copy of his book, which will be remedied this week.

So, if I could ask for further refined advice on building a strongback for constructing this boat.

Thanks again.

Later,

Phil

[ 10-14-2002, 10:13 AM: Message edited by: Tar Devil ]

[Scott Rosen]

Phil,

WoodenBoat sells a very inexpensive book on building the Nutshell Pram, which has photos and a description of a good strongback. It's basically a ladder frame of 2 X 4s. I'm not sure I understand your question, though.

Building the frame for the strongback is a snap. The trick is making sure the station molds, frames, transom and stem are properly placed. Unless the plans for your boat contain patterns or dimensions for station molds and instructions for placement of those items on the strongback, then you're going to have do some very careful measuring. There's nothing that anyone can tell you about that unless they know the particular boat you are building.

[Ross Faneuf]

Scott makes a good suggestion - but possibly the book for the Shellback, a larger boat, would be closer to your dory. I built the Joel White Pooduck Skiff - similar to the Shellback, but larger at 12'10" - and its strongback would work for your dory.

I strongly second what Scott says about setup - the strongback is pretty straight-forward, but careful setup is vital.

[Bruce Hooke]

A standard ladder-type strongback would probably do the job but the traditional approach to dory building is somewhat different from most other boats, and I'm guessing it's this difference that is behind your question. As I think you know, on dories the frames are normally attached to the complete bottom assembly and then the whole works gets bent to the desired curve, usually right-side up as in the photo above, from The Dory Shop, but upside down also works. On page 72 & 73 of my copy of The Dory Book John Gardiner does a very nice job of explaining how to setup a dory upside down. Basically you build a longitudinal strongback that is cut to the curve of the bottom (sort of like a long sawhorse with a curved top) and then you bend the bottom assembly over this by pushing down on it from above (or screwing down through the bottom and later plugging the holes). The stem and transom can then be attached to the floor at the centerline and the frame heads can get braced down to the floor as well, on lines previously marked on the floor to show the right position for each frame. If you need more details I can scan the 2 pages in question from The Dory Book and send them to you but it sounds like you are going to buy a copy of the book, which is much the best way to go. It is a book no dory builder should be without.

- Bruce