dufour arpege Keel bolts

[cygnettrade]

I posted this query about 10 days ago. I must be the first person to have posted and not recieved any replies! Maybe i should have been more explicit. I am trying to figure out the correct method to withdraw a keelbolt from my 30 year old arpege. It does not appear to be a conventional threaded in stud, but more likeley a through bolt. Has anyone ever removed them?? /forums/images/graemlins/confused.gif

 

[tillergirl]

Two posts without a reply!!

I have removed and replaced the keel bolts from my wooden boat; not exactly comparible but some of the experience may help. First are you sre they are through bolts. If so that's the best - you should be able to locate where the heads are in the bottom of the keel. Of course in a 40 year old wooden boat they were big holes which were obvious. I guess dufour may have been more sophisticated and faired off the bottom of the keel in which case locting the bottoms is going to be more difficult. The heads (bottoms) of the bolts will be either another nut to match the inside or a shaped head like a cone. Clear out as much crud from the head of the bolt as possible. If its a nut worth putting a socket and large extension lever and giving it a turn to loosen the whole lot. Clean up inside as much as possible and loosen nut to give sufficient clearance to start driving the bolt down. Opinions can differ here - do you remove nut completely and then ruin the end of the thread as you drive down or use the nut to protect the thread and run the risk of jamming it on the thread by a misaimed blow. I was able to use a large drift inside the nut - the nut thereby locating the end of the drift - and the thread was undamaged. The point about the thread on the bolt is that in all probability once out you are going to replace the bolt since the cost of a new one is the least painful part of the process but if you fail to move it at all you are going to want to put the nut back! Once you start hitting the bolt with as large a hammer as you can, immediately check underneath (it is obvious that you have arranged sufficient clearance underneath the keel to drive the bolt for its full length) to see that there is a similar movement - this is critical because if it is moving up top and not down below then the bolt is folding in the middle and you could be driving the top in a final embrace with the remains of the bottom. If there is similar movement, keep going - you might find it tighten as it drives down but it should be successful. If there is no similar movement some thought is called for. You might try two nuts on the top to see if the bolt will 'undo' in other words pull out the broken top bit (in one of mine, the bolt had completely wasted away and the nut didn't undo from the top part just helped to withdraw the top part of the bolt leaving us with just a glimpse of the spike of the bottom bit in the hole! In these circumstances, conventional wisdom is for a drift to have a hole drilled in its centre to go over the spike and then use that to drive down. This didn't look too successful to us as we could see the spike compressing! Having thought about it for a moment, we got underneather and put a socket on the bottom nut and turning that, the remains of the olt undid itself downwards. We wuz lucky! But I think it would have come out with more driving since it was so badly wasted. In another case, undoing the top nut imparted a twist (as we found later) to the top of the bolt (mild steel) but we were still able to drive it out quite easily.

Most came with using a large Club hammer but a couple needed a start from a Sledge! Used carefully. Although brute force comes into it, I think the key is to have been careful in its application. The other helpful thing was another chum and a selection of robust drifts - a 12" gearbox layshaft was the best - strong and no give.

Studs as I understand it need the keel dropping! or a second nut on the top to allow the first to jam to be used to unscrew the stud.

We found this was not that difficult - not quick but very possible but then I am shallow draft. You won't have the complication of wet wood trying to grip the top of the bolts although of course I have no experience of how fast they are in the GRP.

Why do you want to inspect them? Do you have weeping at the keel joint? This was the main telltale for me and turned out to be correct evidence of bigging failure.

Good luck - are dufour still around to advise on how they fixed the keel?

 

[andy_wilson]

No, but a visit to an agricultural merchansts with the nut or head size should get you an economical socket and extension bar (check long an extension you can fit and swing).

That's the only technique you need, the right socket, and the right extension pieces (and possibly an extra pair of hands).

 

[cygnettrade]

Lots of usefull advice but no real help i'm afraid. Firstly i have no probs removing nuts within bilge. Secondly the keel would appear to flange onto the main hull? i.e the bolts do not go all the way down and through the casting, but are run around within the bilges.