Pictures of Cracked keel Flange, form several weeks ago

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seumask

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Form the thread at Previous thread I am trying for the first time to attach pictures of the break [image]http://i236.photobucket.com/albums/ff264/firefly3572/DSC_0005.jpg[/image] and of the peice broken off

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ok try again
DSC_0005.jpg
 
If all that flange does is prevent the keel from lifting when bolted down, or from dropping right through I can think of two solutions that do not involve any welding.

1) If the remaining flange is adequate to stop the keel dropping too far, then use an angle grinder to clean up and flatten the top surface. Get a piece of steel at least 10 mm thick and drill two holes for the "Hold down studs" Three more holes will be needed to fit the plate to drilled and tapped holes, one on the centre line of the keel and two near the back of the flanges. The bolts for this purpose need not be very big as they do not have to resist a very large upwards force. I hope the hold down studs are long enough to allow this. If not the larger holes in the plate and some specially turned up tubular nuts will do the job.

2) If you can have the keel lifted out, or raise it to a point where the broken area can be worked on, you could cut off the whole flange and grind the metal flat at the top of the keel. Two or more substantial stainless studs could then be put into deep drilled and tapped holes in the keel and a new flange made of steel bolted in place. To do this in a way that will take the weight of the keel on the flange you might need to make the flange extend further back and fit more studs. (I am assuming this is the front end of the keel).

Personally I think method 1) above is the best bet, as the existing flange is probably the best thing to stop the keel dropping too far.
 
That doesn't look like a fresh break to me. Has the piece been left in the water since it broke? If not, I think that the piece has been broken off for some time.

I agree that if you want to repair, the best way will probably be to get something made up which will bolt to the remaining part.

Andy
 
Thank you my current thinking is as your option 1 above, but I'm not sure that in the event of a hard grounding the remaining Flange is adequate to stop the keel droping down at the front.
To my mind the big issue is if we hit the bottom hard this will drive the front of the keel down and I think the way to deal with this would be to drill several large 10mm ish studs down into the keel with one at he front edge of the keel.
Does the forum think that there is enough metal (aprox 35 *25mm) to put the front stud in. I would expect these studs to would come up through the plate and be capped with a nut approximatly between the two hold down studs for the front one that you can see in the photos
 
I agree with the other poster here. That break does look old, so probably the piece broke off a while ago, the two parts were touching each other and and may even have become stuck together. The piece then fell off when subjected to a blow. If the iron section you propose fitting a stud into measures 35mm x 25mm it is big enough for a 10mm stud, provided you have enough depth.

My only concern here is whether 10mm studs are man enough for the scenario you envisage.
 
Yes the strength of the flange especially at the front is important.
I have a vertical lift keel also. When I hit a rock or reef. (sadly too often) the front of the keel tries to go down and the rear of the keel cocks up. (as the bottom front of the keel is forced back)
I have a 5/16 ss bolt at the back to lock the keel down and it invariably gets horribly bent. Likewise the top of the f/g keel at the back get crushed where it hits the hold down bolt.

This damage is not a really bad thing as it all contributes to absorbing the impact forces of the mass of the boat versus the sudden stop of the keel. In my case the keel has a flange on top which is about 12 inches thick. ie the keel is rectangular shape for 12 inches then down to foil shape where it goes through the hull. (this provides stability especially sideways so keel does not have to be bolted down) although that is a safety thing)
So if the keel is dropped or there is a down force at the front I am relying on the hull thickness to stand up to it. (so far so good)(25yrs)

Back to your broken flange. Yes I would agree a new mild steel flange across the top would be a fix. However I wonder if it is really so bad with the broken piece missing? Sorry I would have to see the whole keel thing to be sure but the flange may have cracked from natural causes over a long time It only departed when the keel was dropped. Dropping the keel while in the water is not such a problem as in mine the water in the c/b case under the flange acts like a big cushion to slow down the crash. However to drop it out of the water with the boat in a sling might be something different.

Anyway good luck. If absolutely all else fails you could make a new C/b out of lead and fibreglass. olewill
 
Not my boat, but Firefly3572 has it.
I can see now why the piece of flange (which looks as if it is about 1 inch thick) has broken. My concern remains that 10 mm studs are unlikely to be strong enough if their function is to hold a new top plate which is being expected to reinforce what is left of the flange against further breakage and take the forces involved in a grounding, as well as providing the holes to take the hold down studs.
 
Regarding the age of the crack, it is new but the surface had been exposed to seawater / damp air for two weeks when the picture was taken hence it has oxidised and now looks old.
Thanks for all your comments so far.
 
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