An extra trippy Merlin.

[Gamma1214]

As part of my plans, I'll need to be able to tilt this hull (before glassing the exterior) 90 degrees or so (side-to-side) and I lack the space to tilt the strongback as Jim does so I needed to devise something that would allow me to rotate it in place. I also wanted to make it removable as every hull is unlikely to get this treatment so a stationary SB is still likely to be ok under normal circumstances.

With 3/4 inch plywood forming the SB and 1/2" OSB above, I endeavored to find the center of balance and theorized that it would not be too far below the top of the SB. I measured & marked the center of the beam and screwed on a flange that will accept 3/4 inch black iron pipe.



Then, staying somewhat true to my automotive background, I grabbed a couple of 6 ton jackstands, removed the rams and replaced them with some 5/4 x 1 3/4 inch scraps (Sassafras left over from paddle making in this case but anything would work). I marked and cut out a notch in the top



inserted them in the jack stands, lifted them (slightly) off of the floor and installed a couple of screws to act as stops so that the weight of the SB would be transferred to the base of the jack stands. I also used some paddle scraps to act as wedges to secure the new rams



I traced the footprint of the SB with sharpie so that I could land it in the same spot, inserted 6 inch pipe nipples into each flange...



and lifted the SB onto the improvised jack stands. I'll need to tweak a little to better center the weight on the jack stand base (as it stands, the pivot is almost wide of the edge of the base and that's a bit precarious IMO) but I'm very pleased that the experiment went as well as it did on the first try and that, with about 3 inches of lift, I did not need to remove the feet from the SB



The SB rotated easily in place with enough room to walk around it on both sides and, when lowered back onto the floor, I rechecked and everything was still level & plumb.

I'll adjust the jack stand arrangement tomorrow to keep it centered and I should be ready to start stripping. With one week until enforced social distancing during radiation treatment, I'm very hopeful that I'll be ready to glass this hull by March 5th when I'm, again, cleared for human contact.

The reason that I need this rotation will, hopefully, be evident at that time.

 

[Jim Dodd]

By the looks of your stand, you need just as much space,as simply tilting your strong back.

Adding some weight to the legs to offset the weight of the forms and strips.
Looks like you are getting there.

Good luck with your Radiation Treatment !

Jim

 

[Cruiser]

I am seeing a triangular support on the ends, with that nipple at the apex, in fact if you want to get around the back and forth weakness, maybe some more like a large version of a painters Pyramid

That wouldn't use much material and should give solid end support.

 

[Gamma1214]

I stopped over briefly tonight, primarily to fix the jack stand set-up.

By the looks of your stand, you need just as much space,as simply tilting your strong back.

No, when I tilted it without lifting the base off of the ground, the hull was resting on the infeed table. By using the pipe nipples, I've moved the point of rotation from the floor to the top of the strongback and I can walk between the infeed table and the top of the forms.

I am seeing a triangular support on the ends, with that nipple at the apex, in fact if you want to get around the back and forth weakness, maybe some more like a large version of a painters Pyramid

I can see how that would work but I think the jack stands will work for the task at hand. I expect that the hull will only need to be supported as a rotational assembly for an hour or two, I probably won't rotate past 45 degrees and I'll have a support mid-hull to further stabilize it.

Good luck with your Radiation Treatment !

Thanks Jim. I'm not at all worried but I appreciate it nonetheless.

OK... I really didn't like the position of the point of rotation in my last picture above. The weight was borne by the ram almost directly above the outside edge of the stand base and (as anyone here can attest, getting the weight too far outside of the edge of a rotationally-capable assembly can be catastrophic).

I was seeing two problems: 1st, the ram could move too freely in the base and the top of the stand did not have enough surface area to stabilize it and 2nd, the wedge made the situation worse by encouraging the ram to tilt as it passed through the top of the stand.

I solved it by taking some scraps of OSB, cutting them into 6 1/2x 8 inch rectangles & fitting them into the bottom of the jack stand. I then inserted the ram, measured the distance from the top of the stand to the screws I'd installed previously & cut the corresponding length off of the bottom of the ram. A single screw through the OSB and into the bottom of the ram stabilized the set-up a lot and the wedge now tightened the ram without forcing it out of alignment.



I placed the SB onto the revised stands and I am very confident that this will do.



I did put one strip on around the sheer but I'm undecided about whether to fix or shim that station... I guess that will be an in-game decision sometime next week as I've got tons of crap to get done before Wednesday.

It's also really weird looking at these forms after building the Raven. This boat looks tiny by comparison and (especially as the Raven turned out well and the stations were true) I was tempted to reinstall the Raven forms and just build another (but I won't... at least not yet...)