Bottom frames

cusoak · Post by **cusoak** » Sat Feb 14, 2009 9:15 am

A friend of mine is redoing the bottom of a 1951 Chris Craft Special Runabout. I was there the other day to help drill the drive shaft hole In the keel. While doing so I was looking at what he had replaced frame wise. Thats when I noticed that the top of some of the frame did not line up with the plank notch in the keel. It was down below it. This was the case on some of the frames. Taking a 2Ft leveland placing it on the top of the frame to see how far down it was I found that he had cut a concave in the top of all of the frames. Question is this, 1 should the frames have this concave in them or should they be straight.2 From the transon forward how far towardwthe bow is the bottom straight and flat,About how many frames. Thanks Jeff

Bill Basler · Post by **Bill Basler** » Sat Feb 14, 2009 9:59 am

I would suggest holding on further progress until you have the chance to investigate more. I am sure you will get some qualified responses here. Off the top, something does not sound right. Before I jump to conclusions though, please clarify a couple of thing.

When you say the "tops" of some of the frames, I am thinking (since you are getting ready to drill the shaft hole) the boat is still upside-down? If so, and you say "top" is it actually the bottom edge of the frame, that does not properly notch down over the keel?

If I am on track, it sounds like a couple of the frames would contact a straight edge properly fore to aft, but other frames would not?

Am I correct on this assumption? Can you post a couple of photos? I would hold on things until you get some thoughts.

cusoak · Post by **cusoak** » Sat Feb 14, 2009 10:14 am

Yes you are correct.the boat us turned over and it would be the bottom or plank side. I just redid my 66 Resorter (Century) and all of the plank side of the frames were straight from chine to the keel. He used the old frames as patterns. I am wondering if this could have accured do to setting of a trailer that did not support the bottom correctly.Jeff

Bill Basler · Post by **Bill Basler** » Sat Feb 14, 2009 10:18 am

Most certainly this could be the case. Any problems introduced over time will be there to be replicated unless measures are taken to get the hull back to its proper shape.

Can you get some photos? As you are getting ready to drill the shaft hole, does this mean the inner bottom and outer planks are on?

Al Benton · Post by **Al Benton** » Sat Feb 14, 2009 10:33 am

My 1948, 17' Deluxe sat on a trailer for years before I acquired her. The result was that keel settled in unsupported areas, was bowed and had to be replaced.

The Archives has drawings for the 1947, 19' Racing Runabout that includes a note regarding flatness of the hull from the transom forward to some minimum distance. It's on Drawing No. A-7104. The drawings I purchased for my Deluxe includes the same warning.

Al

tph · Post by **tph** » Sun Feb 15, 2009 11:00 am

Jeff,
You are correct on your Century having bottom frames
that are straight from keel to chine. Chris craft
for the twenties until the late fifties have a
concave shape. See pic. 1. Sometime around 1959
chris craft changed to a convex shape bottom frame.
see pic. 2.Hope this helps.
tom
vintage marine

kendorado · Post by **kendorado** » Tue Feb 17, 2009 9:02 pm

Definately STOP working. If your friend used the original frames for patterns and they do not contact the keel (did he thru-bolt them?) then I would suspect the chine has spread. This should have been determined after leveling the hull then measuring the centerline to the chine (all the way down the keel).

Bottom frames

Bottom frames

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Bottom frames

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