Keel Bolts - material & where to get them.

ianc1200

ianc1200

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I posted a thread back in early 2024 - Drilling cast iron for new keelbolts - well on Wednesday this week I managed to drill the first bore. The lack of being able to drill CI caused a lot of pain/heartache/thinking the whole restoration was not possible. I went through lots of alternatives, different types of drill bits, different cutting & clearance angles on my Tormek grinder, differents drills & presses. Eventually used a 110V Type E Blank and Decker drill, very old, very heavy, 400 rpm, high torque, a drill press free off of FB Marketplace, again very old, heavy with a big powerful lever arm. Found the outer part of the CI much harder than the inner core. Did use a pilot drill for first inch only, then a HSS drill sharpened to 140 degree cutting angle, 14 degree clearance angle. My 450mm drill bit wasn't long enough, so used a 600mm long tungsten tipped masonry drill bit for final inch. Used small amount of cutting oil only.

But to my question -

For keelbolts I had, back then, bought 16mm A4 SS studding, nuts & washers, but in the multiple discussions I've had since regarding my failure to drill the holes, the suggestion I should use bolts, with the head under the keel. I haven't had any luck finding A4 SS 16mm dia bolts 450mm long. Any suggestions?

(I'm sure somebody will say I should use silicon bronze, but my experience is SB isn't all that strong, but if that's the only option (because I can't get the SS bolts I need) where to go to get SB bolts?)
 
I had keel bolts made of 316 bar (actually 20mm prop shaft) threaded both ends and the nuts at the bottom sat in a pocket in the keel. Still there after 20 years when I sold the boat. Important to make sure there is plenty of sealant in the bores and the keel/hull joint. Doubt you will find bolts that length.
 
Tranona said:
I had keel bolts made of 316 bar (actually 20mm prop shaft) threaded both ends and the nuts at the bottom sat in a pocket in the keel. Still there after 20 years when I sold the boat. Important to make sure there is plenty of sealant in the bores and the keel/hull joint. Doubt you will find bolts that length.
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I doubt it too. You can always weld the lower nut onto the threaded bar.
 
I believe my XOD has this done though I’ve never seen that end, the recesses are filled with P38. The top ends have nuts. The front and rear bolts have nuts which are also lifting rings. Lift the floorboards and clip the strops on, so much better and more civilised than slings underneath.
 
If you can find it wrought iron is excellent, Years ago i bought a set of forged taper head bolts from Chris Topp for a job. His company Topp & Co are still going, might be expensive but for keelbolts will outlast stainless & doesnt suffer from crevice corrosion.
 
I deal with wrought iron gates occasionally, usually in front of old big houses. Bit of a nightmare as, big & heavy, plus, no welding, all rivited and screwed, some well over a century old. Making replacement bits is tricky. But, a thought, if one could find some, the vertical rods might make good keel bolts?

The guys at Ironbridge still produce wrought iron? Or is that Chris Topp?
 
Decided to go with the SS I already have, and get a local workshop to weld the nuts, then chamfer the upper side of the nut to match the chamfer I intend putting on bottomside of the keel.
 
If using Stainless make damn sure the Rods they use are the same grade, I say this as using 304 rods or wire on 316 material may result in rapid crevice corrosion.
I have seen this twice, once on a Lead keeled boat that the owner had rebolted the keel with 316 stainless, they failed after just 5 years afloat with over half the bolts sheared completely, Another was a Stainless rudder shaft & blade welded on, both marine grade but cheaper rods were used, the welds had completely hollowed out underneath.
 
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