STRONGBACK DISCUSSION etc.

[ebb]

Kurt, Ian's tip is a good one, too.

Critique. Caps and pipe threading, not many turns. A coupling might provide a bit more length. Maybe threads could be deepened with more turns of thread doing the work of holding the roof up. The opposing thread of the coupling could be cut off. IE the coupling cut in half.
The coupling has a 'flat' top. You'd have to have a plate on top to take the rim when you are tightening against the wooden beam. And this plate could have a stud or some washers welded on it to hold the coupling and the pipe exactly in place when it's screwed up in compression.

Imagine the torque that post would take with a human swinging around on it.

The bottom of the post could be handled in the same way. The plate on the Ariel might turn out to be a convenient piece of larger angle supported over the keel and cut to fit the angle of the hull sides like a floor. I would hold it back from the hull a little. The horizontal flange would have the post connect ie the pipe inserted over some welded on washers. The vertical face of the angle could be for the bolts holding it in place. No bolt heads or angle iron on top. The post would appear to be floating.

I would probably cheat the compression post in place by jacking the beam with a bottle jack. You know, just put everything eggzactly where you want it while the jack has the pressure. Do again to get it purrfec. I'd see if you even need a coupling extension with the bottlejack. Tremendous pressure can be achieved with a jack. Might just cut all the parts to fit and slip em in place.

Galvanizing is the best coating you can put on steel. Galvanizing is cheap and sometimes they will take pity on the poor sailor bringing in his precious handmade stuff and put it in a bucket with another job. You'd also be galvanizing your new compression post INSIDE as well.
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Interesting observation on the stringers. Location may be a trick of camera angles. The stringers in 338 were what the shelves rested on. Guess that their place on the Ariel hull is pretty much similar. Couple inches up or down?
338's stringers appeared to be jammed into place and slapped on with matt. They are for the most part crooked and not even parallel with the sheer as they could be.
I just decided to let them be. But added more stringer completely to the bow and all the way to the end of the cockpit. Added to make them appear like they came factory. Think the stringer going toward the bow sloped up some because it looked better.
The stringers, of course, are not level with the waterline.

My feeling at the time was to even the loads on the hull and I didn't feel that the stringers should just stop where it was convenient for Everett. What you see are stringers going clear to the bow. While they are stiffening members they are also stress points, so I have also radiused the corners with fillets. Argueable if any of this is really necessary, but I feel better that the boat is more symetrical, if that is the word.

I see settees and berths and other tabbed-in furniture providing longitudinal strength like the stringers. More so, because they are web frames providing immense stiffning.
I feel that these lines should be extended wherever possible in a remodel to elimnate hard points.

[ebb]

About this compression post thing.
I think the post should be designed as a single (welded) piece that is bolted thru well fitted flanges to the beam and the floor. There should be no way that it could come apart.

There could a scenario where the boat is thrown on its side and the compression post be popped out of its seats. Pipe over flat washers as in the example previously. Possible. Could think that the compression post is holding the cabin up as well as holding it together.

Maybe this is a simpler solution: If the overhead beam is wide enough for an actual pipe flange (so named) which is a common pipe threaded fitting usually with chamfered holes for screws already drilled, one of those at each end of the pipe to widen the point load and hold it in place. They come threaded for pipe or unthreaded like tube fittings. Various collar heights and amount of thread. You use the cheap threaded ones, using that bottle jack to positively hold open the distance between beam and floor, the pipe would be micro fitted by tightening or loosening the flanges. Then welded to set the length of the post and close the seams and lock-in the flanges. Making it a single piece. Then galvanized, have to zinc the threads and fill the crevises.

Have to decided for yerself if the screws you put thru the flanges into wood are enough. The post is going to get yanked on, screws in sheer, so it's probably good. imco

This structure is simple - allowing positive fastening - and easy removal.
Careful cranking on that jack. Don't want to distort anything. It's an extra hand.