Frames went boing!

[Carrpelll]

I am in the process of replacing the frames on the bottom of my 18' Riviera and when I unbolted and removed one of the frames it "sprung" into a different shape. I had to push it back down with quite a bit of force to get it to lay back down to get the bolt holes to line up again. So I removed another frame and it did the same thing.
Is this common? It would seem wrong to make a replacement frame using the old one (once it is removed) to make a pattern from.
Anyone else experience this?

[Carrpelll]

Sorry. I forgot to mention that the chines have been removed and I unbolted the bottom frame from the side frame and it sprung up about an inch or more - which is actually down because the boat is, of course, inverted.

[parroteyes]

It does not seem likely that a frame bolted in place for sixty years would spring back an inch. I wonder how you have the boat supported. It may be that you have a lot of torque introduced by the weight of the boat on the supports.

I don't have enough experience to say what's normal but my '46 didn't do that.

[Carrpelll]

I have to agree that makes sense but I have the entire hull supported inside and out before I started to take anything apart.
I built a craddle inside the cockpit and supported the outside with 10 - 1 x 4 wood supports from the rubrail location to the floor so I don't think the hull is sagging under it's own weight but stranger things can happen.
The first frame I removed was #8 from the front and the second one was #6 from the front and that one only sprung about 1/2"
Carroll

[jim g]

Does the hull or any of the framework have past repairs done to it? If so depending on how the repairs or patches were done there could be a twist or sag in the hull.

[parroteyes]

I supported mine on the engine stringers. I only put supports under (upside down) at the top decking to stabilize the sides as I removed the frames, not to support the boat at all. All of the weight is carried by the bottom frames to the stringers and then to the supports.

[boat_art]

I would suggest replacing one component at a time. If the chines have been removed they should be replaced before any other components are removed. I still dont see how any frame should spring out of place unless there is another force acting on it.

[boat_art]

Parrroteyes has the right idea, support all weight on the engine stringers only.
Tom

[Carrpelll]

The inside cradle is fastened to the stringers so that was done correctly.
I was just curious if the frames can try to straighten out along the grain. That might explain why there are a few of the frames are split along the grain, as well. But no bolts were sheared. Hmmm.
I will try to take some pictures and post them.
I have to admit - the boat sat there for a year upside down with the bottom planks removed and low humidity, especially now.
C

[cewplatt]

I'm doing a complete rebuild on a 20' Riviera. If you've removed the chine and the hull planking, I wouldn't be surprised by that much movement. Make sure to support the bilge stringers. I've replaced the bilge stringers and am supporting them at both ends and the middle. I built a ladder frame from 2 X 10's with leveling feet and cross bracing. I want to replace the frames without removing the sides and battens to prevent what you're seeing, but starting to realize this will be tedious and time consuming.

Regards,

Clay Platt

[Carrpelll]

So here is what I think happened.
If you just support the hull only by the engine stringers, the entire weight of the hull is putting forces on all of the frames. I supported the hull with 1 x 4's along the shear but only after the boat sat for a while supported by only the engine stringers.
I am convinced the weight of the hull stressed and bent the frames before I was able to support the hull along the shear. When I removed the bolts in the frames - they sprung back into their original shape.
The solution was to lift the hull at the covering board with a floor jack until the bolt holes in the bottom frames lined up with holes in the side frames - then re-supported the hull along the shear.
I think I am going to have a good day!

[parroteyes]

That certainly makes sense, particularly if you removed the bottom before it sat for a long time. The bottom planks contribute to the strength of the boat and without them the frames may not be able to sustain their shape.

You have given us all something else to think about.

Thanks.

[iwally]

The solution was to lift the hull at the covering board with a floor jack until the bolt holes in the bottom frames lined up with holes in the side frames - then re-supported the hull along the shear.

Er um, I guess I'm a little dense, can you explain this a bit more? I'm still not sure I know just how you did this. You put a (one) floor jack at the covering board (at the nose?) until the bottom & side bolt holes lined up - in which dimension?

I think I need more coffee.

[boat_art]

I have done at least 30 new bottoms on runabouts and have never had this problem. Again, the main thing is to remove and replace one component at a time while the hull is supported on the stringers. The chines having been removed along with frames will obviously put undue stress on the entire remaining components. I know many other pros and none has ever had this much difficulty.

[boat_art]

I will add that if I replace the chines, then I add blocks under the covering boards to prevent sag but the stringers must continue to be the main support. When replacing chines I do them first, then any frames that need to be replaced.

[Carrpelll]

I will post a few pictures tonight. I have a few broken frames and maybe that is enough to 'load' the remaining frames. I don't know but there was a lot of stress on the one frame I removed. and the second one I tested.
I am not sure how you would remove any frames - let alone install an new one while the chines are still on??

Carroll

[boat_art]

This is a Holiday, but the idea is there. The frames are taken apart as they are removed.