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The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.
I am replacing the keel hanger bolts and would like to correctly torque the bolts. I called Catalina Direct and they informed me there is no factory spec for torque setting. Is anyone aware of the proper torque for these four bolts? This is a swing keel model used in fresh water. I replaced the bolts about 15 years ago and can't remember if I had torque settings or not at the time.
Mike
Mike Roetter '83 C25 #3568 SK/SR Marblehead on Lake Erie
Mike, if those bolts haven't been touched for 15 years, the threads may have seized and you may have difficulty removing them. Be very careful you don't break them off. If they are hard to move, put some heat on them.
I got curious about this myself, as I will be reworking and rehanging my keel within a few months. So, I looked in the Machinery's Handbook and found an equation and a table of values for various grade steel bolts. They did not include stainless steel, but a number of online sources seem to put 18-8 stainless (the grade that seems to be used in most fasteners) at close to grade 5 carbon steel. Using those figures from the table in the equation give a recommend wrench torque around 18 ft-lbs for 5/16" bolts. This is "...a rough idea of the torque necessary to properly tension a bolt..." and it is for unlubricated fasteners.
Any time you use SS connectors into SS (bolts or machine screws into nuts or into threaded holes) USE A LUBRICANT! Stainless is notorious for galling: it doesn't always happen, so some people believe it's an unwarranted fear, but even on this forum there have been confirmations of sad experiences. I use Tef-Gel, although some recommend Lanocote. Even light oil will help when the connector goes in, although it might not help when it's time to remove it (fears of properly torqued lube'd connectors working loose have never been demonstrated to my knowledge). In any case, Machinery's Handbook recommends reducing the wrench torque by 10% for lube'd connectors.
All this indicates that the answer to your question is probably around 16 ft-lbs. This seems low to me, but it suggests that the amount of force intuitively needed is more than is actually necessary. Just for a quick reality check, I happen to have a service manual for my Tohatsu outboard motor handy, and it lists "standard torque" for M8x1.25 bolts (comparable to the 5/16" keel hanger bolts) as 8 - 11 lb-ft, although they recommend as much as 20 - 22 lb-ft for the cylinder head bolts (into threaded holes in the aluminum block). Seems like over-tightening the keel hanger bolts a bit (lube'd, of course) might not hurt.
Also, I would agree with Jim about using caution in removing them. I'd be inclined to use an impact wrench rather than simple torque, as the pounding could help break down any corrosion inside the threads. I'd be wary of applying heat in that location, surrounded by plastic; the "blue wrench" could cause more harm than good.
The trouble with a destination - any destination, really - is that it interrupts The Journey.
Lee Panza SR/SK #2134 San Francisco Bay (Brisbane, CA)
Thanks for the advice. 18 ft.lbs. seems a little light but I'll know more by the feel when I install them.
Between my former C22 and this boat, I've done two keel boat installations and I know to be very careful. Fortunately, I sail in fresh water so, hopefully, I won't have seized bolts. On my C22, some DPO used a mild steel bolt which had to be carefully drilled and chiseled out which took at least 8 hours on my back under the boat.(An easy out wouldn't work as the bolt was really corroded and seized.) I have a healthy respect for taking care on removing keel boats. That DPO probably still has ringing ears.
Mike
Mike Roetter '83 C25 #3568 SK/SR Marblehead on Lake Erie
I think the Catalina 25 swing keel hanger bolts are 3/8-NC. I just did a Catalina 22, and those were 5/16-NC. I apply polysulfide sealant to both lubricate the swing keel bolt threads and prevent loosening.
I think the Catalina 25 swing keel hanger bolts are 3/8-NC...
Interesting: the page from the Catalina 25 Parts Catalog (available from this Association Website in the Manuals and Brochures section) indicates the bolts are 3/8" while another drawing, also apparently from Catalina, indicates 5/16". This other shop drawing is among a set that I guess someone had posted at some time in the past, and I saved them. They were faxed from Catalina Yachts on Oct. 14, '99. This one is titled "Keel Hanger Bolt Repair" and it indicates both C-22 and C-25 were using 5/16" bolts. I'm wondering if somewhere during the model run this was changed and the C-25 switched to 3/8".
Using 3/8" in the Machinery's Handbook formula raises the recommended torque to about 31 ft-lbs, or about 28 with lubrication (I'm surprised how much the value changed).
But I'm still wondering if the early models used 5/16" bolts.
The trouble with a destination - any destination, really - is that it interrupts The Journey.
Lee Panza SR/SK #2134 San Francisco Bay (Brisbane, CA)
Notice: The advice given on this site is based upon individual or quoted experience, yours may differ. The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.