Is this characteristic?

[higgs]

We were pulling boats at the YC today. A Newport 33 or 34 came out. Nice Boat, but the 6 ft draft keel pendulumed a good inch or inch and a half. Grab the keel and with little effort you could swing it back and forth. One could see flexing in the hull near the keel attachment point. When we set her down on the keel, the hull surrounding the keel area flexed inwards slightly. The owner claims he has checked with other Newport owners and this is how the boat is designed. What do you think?

 

[Ross]

You mean that the joint is tight but there is enough flexibility in the hull to allow this movement? I should think that fatigue will take it toll before long and the bottom of the boat will start showing stress cracks.

 

[higgs]

Me too.

 

[RichH]

the boat is blocked wrong at the keel. There should be one block under the leading edge of the keel and one block ..... 'just under' where the aft part of the keel joins the hull. If you put the aft block any further aft, typically near the trailing edge, the keel will 'begin to rotate' INTO the hull at the aft end.

Many Pearsons, Newports, ODays, and other 'thin' hull boats do this. All caused by having the aft block ..... too damn far aft under the keel. When the keel aft end goes 'up' you will also get some pretty severe hull deflections just behind the keel - good way to delaminate the hull.

 

[Ross]

So what happens when you bump the bottom and the keel stops before the boat does?

 

[FastOlson]

"depressingly normal"

There is a good chance that this particular Newport, like others, had internal ballast. There were Q.C. problems with these @ Capital Yachts and I saw one that had to have the frp keel area cut open and quite a bit of work done on the internal ballast. The good news was that it had lead shot, and the bad news was that the uncured resin around the shot allowed a lot of it to run out on the ground when keel cavity was opened for water intrusion.
These were never strong boats, but more from the "just enough and not a penny more" school of engineering.

Good boats for protected waters and sunny days... and don't bang into things with 'em.


The Newport dealer used to warn close friends away from 'em due to persistent hull/deck leaks. I do not believe that Cap.Yachts paid enough attention to proper assembly.
Personal opinion being stated, and YMMV.

L

 

[RichH]

So what happens when you bump the bottom and the keel stops before the boat does?

Not much, as the boat and keel are being supported by the water (buoyancy) and the weight/mass of the keel is keeping the hull 'taught'. To do any damage to such 'build' one would have to be sailing 'backwards' at a fast speed.

 

[JVB]

Does any organization keep records on boats sinking from structural failures ?

 

[DianaOfBurlington]

Um, no, that is bad. Really bad. You shouldn't be able, by one man's strength, bend the keel anywhere that you could actually measure it with a ruler. You should, instead, be able to wiggle the whole boat a little in the blocking.

And the hull should NOT 'oil-can' anywhere near the keel attachment area. Many builders deliberately beef-up the laminations here. On my H25 I added backing plates to the keel bolts and bonded them permanently to the hull. I also rebedded the bunk fronts (structural to the hull) and main bulkhead and provided joists for the cabin sole as well. After the keel was rebedded with 5200, and before I had tightened all the keel-bolt nuts, the yard moved the boat and the keel did not fall off. That's 5200 for you.

I also realized, after a great deal of debate, that the purpose of the fiberglass around the keel/hull joint is to keel the 5200 from flexing more than it would without it. It will be adequately rigid and yet still flex out of necessity, and the fiberglass/lead joint will always need attention, but after the boat has been sitting a whole winter out of the water it should need only a bit of 5200 filling or even nothing at all.

BTW-- I got my boat as a 'derelict' because the keel/hull joint was leaking after having been redone by an amateur with the wrong 'caulk'. As a boatbuilder by trade I say 5200 is the ONLY acceptable compound for this application.