Need some advice

[reeljob]

I had built the strongback for my Simmons and I thought it was going to work out fine. I unfortunately did not cut the notches for the frames very well, and have tried to account for this. I had tried using squared of MDF to create "notches" on either side, but they did not work out so well either. Also, I've concluded that the whole assembly moves around too much. AS it is, there are three MDF/2x4 sawhorse like braces. There are 2x4 boards bracing these on the diagonal on wither side. It seems to move around too much. Would fastening it to the floor alleviate this problem, or should I add some more bracing?

As for the strongback itself, I'm considering screwing a wide strip of 3/4" ply on either side. This way, I can cut the notches again and it will give me something solid to screw the frames to.

Any suggestions to help me out?

Thanks

[GregH]

As you suggest, additional diagonal bracing seems to be in order- add opposing diagonals so that an "X" is formed between each station. make sure it's level and square, then use some construction adhesive to bond it to the floor.

[pipefitter]

You don't have to screw the frames to the notches. Make some thin wedges and drive them in the notches to take up the slack.This will help square the frames. Screw rat run(1x2 etc) battens to the underside of the frames which will tie them all together and then brace the rat runs.Put the rats out as far to the ends of the frames as possible. You can overlap these side by side to make up for the difference in frame lengths.You should have a dual stretchers near the bottoms of your horses to tie them all together. Then you can cross brace the frames to the stretchers which will give a better bracing angle. This way you can also fasten the cross braces where they intersect eachother. You can brace from the face of some of the frames if you want to for initial control bracing but the rats will allow you to put less screw holes in your nice frames.

[reeljob]

Thanks for the replies. PF- I like the idea of not screwing into the frames. I dodn;t realize a wede would hold them securely enough. I'm a little unclear on a couple of things:
"dual stretchers near the bottoms of your horses"- do you mean boards attatched to the bases of the horses running the length of the jig?
"cross brace the frames to the stretchers"- would this mean creating an X between the frames and the stretchers running the length of the jig on the floor?

Another question- how did you support the stem before you attatched the chines and garboard? I'm not really sure if it is best to attatch it to the strongback somehow or to make a seperate stand for it.

THanks

[pipefitter]

Yes RJ. the stretchers to tie the horses together. You might be able to get away with one single stretcher in the middle and just angle brace to that one. I was thinking 2 to keep your horses square and a little more substantial. And yes to creating an X with the braces is always better because once you adjust them,you can zap a couple screws where they cross and it will help lock everything in. Here is how I held the stem in place. It was crude but since it was just temporary until I got the chines and first sideplanks ("garboards" in the plans) on.
http://home.earthlink.net/~tigmaster41/sitebuildercontent/sitebuilderpictures/00610016.jpg

It consists of 2 sticks going to a cross bar on the leg of the jig and then those 2 are subdued with a ply scrap creating an A. I have been looking at the pics of your build periodically and it's looking good.

[pipefitter]

It just occurred to me as to why I didn't need to use screws in the strongback notches. In the 18,the keelson goes on before the chines. You can tack screw the keelson to the jig if you really need to keep anything centered.Between the battens tying the floors all together from the underside and the cross bracing,it wont go anywhere once you have it all centered and true. The wedges make it tight enough yet adjustable that you can adjust the floors to keep your centerline true.Once the keelson is on though they aren't going to move off centerline.Also,put both chines on at the same time so they torque the floor frames evenly from both sides. Hope this helps.

[reeljob]

Thanks, PF- got some lumber from Lowes today. I like your stem setup. As for securing the frames, I'll still wedge them in the strogback, and i'll screw them to x braces from the floor. It will be a lot of work to set up but the boat will come out straight. I wonder how Simmons made his strongback- probably was a lot simpler that what I'm doing.

[pipefitter]

I am thinking that Simmons might have possibly had a wood floor to brace to or a more permanent jig since he built so many of the same boats.

[reeljob]

I think I;ve gotten this thing to work. I cut the notches in 4" squares of 3/4" ply. Screwed those in at the right spots, made new brackets to hold the strongback to the horses, and have been gluing it to the floor. Added some braces along the bottom. Started to stick frames in it- supporting them with a piece of 1x pine towards the end of the frame. I'd like to cross them, but the strongback is so wide and I;ve got other braces on the side so it won;t work. I think this will hold up much better though.

http://i74.photobucket.com/albums/i254/reeljob/DSC00839.jpg
http://i74.photobucket.com/albums/i254/reeljob/DSC00852.jpg
http://i74.photobucket.com/albums/i254/reeljob/DSC00845.jpg

[pipefitter]

That's ought to do it.

[donald branscom]

You don't have to screw the frames to the notches. Make some thin wedges and drive them in the notches to take up the slack.This will help square the frames. Screw rat run(1x2 etc) battens to the underside of the frames which will tie them all together and then brace the rat runs.Put the rats out as far to the ends of the frames as possible. You can overlap these side by side to make up for the difference in frame lengths.You should have a dual stretchers near the bottoms of your horses to tie them all together. Then you can cross brace the frames to the stretchers which will give a better bracing angle. This way you can also fasten the cross braces where they intersect eachother. You can brace from the face of some of the frames if you want to for initial control bracing but the rats will allow you to put less screw holes in your nice frames.


Rat run - wow I learn stuff every day.

[pipefitter]

Sorry about that. I was subject to working with old timers and alot of the terminology stuck and rat battens sounded too similar to some names they used to call eachother.

[Dave Carnell]

Simmons didn't use a backbone as shown in the plans. I developed that procedure for one-off building before I understood his actual building method. He didn't build the transom-motor well assembly as in the plans either.

Basically, he cut the two bottom side planks to patterns. He bent these around 2-3 spacers he had, pulled them together onto the stem and onto the bottom board of the transom (from a pattern). Without the document to refer to I am fuzzy on the rest of the details.

The Cape Fear Museum sells "How Simmons Built Sea-Skiffs writtten from a talk by Russ Ketterman who worked in the shop and the sketches he used to illustrate it, if you are interested.

The plans are the conception of a chemical engineer turned naval architect.

[erster]

He bent these around 2-3 spacers he had, pulled them together onto the stem and onto the bottom board of the transom

Actually Dave, this technigue has always been a tried and trued way of most skiff builders long the mid atlantic states and quite possibly the way he thought in the beginning that it was to be done, which in turns gives you a true and fair shape. Several stiffeners and a transom, and bend the planking was almost always the way that most all cedar working skiffs came about. This changed depending on the lengths of planks sometimes and the required sized for the boat. Most of the time, supports were just stuck in the dirt.

On the Chesepeake Bay, the stems were actually stuck deep in the dirt and this stiffened the structure in the foward section in the building process for most all crab skiffs and deadrise working hulls.


I don't know but I bet in the beginning, he made templates that created the bottom frames from that shape, after the initial bending, and continued using the same sets for production. The reason that I think this, is the practice of butting the bottom frames to the chines using the frames for the decking as an all in one use for them, unlike the normal practice of smaller frames and deck beams too, a two part process.

[cs]

Okay, not that I have a clue, but I thought I would add what I did when I built my canoe.

I took a scrap LVL and ripped it in two and created a T. I than attached the forms to the LVL with Simpson Hurricane clips backed up with small wood block on the back side. Solid as a rock.

http://img.clubphoto.com/jerboa/17839561/600/null/image.jpg

Chad

[pipefitter]

Now THAT's a strongback.

[pipefitter]

I saw other boats built using the earth as the jig here in FL. It's where I got the idea of the uprights for my building jig. I didn't plant the stem because I didn't know how long it would be sitting like that and the wood lice would have made a quick and dirty condo out of the LL pine in short order.I did think about it though.Instead I made a caisson from a wood box of PT that wouldn't settle in the sandy soil and had the stem mounted to that. The box is in the picture although removed by that point after the stem was braced.I didn't want the rains undermining horses and such so I concreted posts in. Once it was time to flip the boat,I sawed them off,using them for the supports of a crude cradle made from the cutoffs. I tried to recycle all the parts as much as possible. The strongback worked fine.
http://home.earthlink.net/~tigmaster41/sitebuildercontent/sitebuilderpictures/00610016.jpg

If you look below the transom,there is a board that runs underneath that is dead parallel to the strong back. I don't trust bubble levels in so many feet. I used a water hose level. This way I could reference the transom angle with both a angle finder and a bevel guage off of that board or a speed square and a straightedge. Just incase something moved in the process or over time. After it was set,I used shims to prop the transom on that board and reference marks that would have shown settling or movement. I am sure a level would have sufficed to set the strongback but the lumber wasn't straight. I needed something substantial to straighten it to. Although it looks and sounds like alot,I have 4 hrs in the jig.Most of the other parts were from construction sites scrap piles that a carpenter buddy retrieved from the job. IIRC,I had about $24 in it. I liked using the notched jig. It was one of those "set it and forget it" components that didn't require any adjustment after the fact.

Notice my fancy workbench which consists of 3- 2x10x16' PT that were also donated as leftovers from a deck job. :)