Re-torquing Keel Bolts

[weephee]

I am finally coming down to the short strokes in restoring my Columbia 8.3 sailboat. One of the final tasks I wanted to do was to retorque the keel bolts. In searching Google I found an article that said you should never, ever retorque these bolts and if you do the bolts will need to be replaced. This makes no sense to me so I thought I'd ask the experts here what I should do. I also have never been able to find the specs on how tight these nuts should be. The nuts are 1 1/8 inches. I put a long wrench on one and with some effort I was able to tighten it a little. Two question then, should I retorque them and where can I find the torque specs. Thanks again
Larry

[Gary M]

Yes you probably should re-torque, which means finding a suitable torque wrench. No way you can guess at it and you do not want to over torque.

As to what they should be torque at there are standard tables for torquing SS rod that should be OK but if you can find the builders spec so much the better.

[c40eb]

I have a 30' Sabre, and the manual states the keel bolts should be checked and torqued (to 90 foot pounds), as necessary.

From the manual:

"...Occasionally, water from the bilge may seep through this crack when boats are hauled. This would be due to a slight leak at a keel bolt, which can be readily be overcome by tightening the keel bolt nuts. As part of launching procedure, check all keel bolt nuts for tightness to 90 foot pounds before the boat is lifted out of the cradle."

Now...I don't know what you're boat manufacturer would say, but I can't see why you wouldn't want to check and tighten as needed.

[weephee]

Thanks for the replies. I'd say they are certainly not at 90 ft lbs if I can tighten with a wrench. The Columbia boat is no longer made so there is no contacting the manufacturer but there is a site that has the original boat dwgs so I will order the one for the keel and hopefully it will tell me the torque. Would it be safe to say the torque would be at least 90 lbs. Thanks

[c40eb]

I'd hesitate to say what to tighten your bolts to...as it most likely depends on the size. Hopefully, you can find out from someone who has your model, or at least more knowledge.

Sorry!

[TommyD]

First start with the bolt size.. typically manufacturers use a bolt size appropriate to the load they will encounter with some safety margin. You would be amazed by how much linear force a thread will transmit because of the mechanical efficiency. 90 ft-lbs is a literally a boat load of force.

Using the simple calculator here

http://www.engineersedge.com/calcula...orque_calc.htm

a 1" bolt @ 90 ft-lbs transmits 960 lbs of linear force. If you have a half dozen, that is close to 3 Tons of clamp.

Torque with caution, & not all at once.

TD

[weephee]

Thanks C40EB. TommyD, there are 6, 3/4 inch bolts with 1 3/8 inch nuts. The lead keel weighs 3100 lbs. I just read in my manual that the bolts should be tightened every year but unfortunately doesn't say how tight.

[Sabreman]

On my Sabre 28 and now on the 38, I apply a simple approach. With the boat hauled and blocked (i.e., resting on its keel), I use an appropriate socket with a 3/4" ratchet and a 12" extension pipe slipped over the handle. I then tighten the nuts as much as I am able while bracing my feet against the mast, seats, etc. The keel boats are at least 1" and I am not nearly strong enough to break them (perhaps others are more manly than I ). In 23 years of boat ownership, the best that I've been able to tighten a bolt was 1/16th to at most 1/8th of a turn. This spring, I was only able to move 1 bolt. Good enough.

[RichH]

Proper torquing REQUIRES that the bolts be properly lubricated, and requires that the 'torquing' be done in increments and 'reverses'. .... Unless the manufacturer (now long out of business) listed otherwise.

If you dont lubricate, dont 'increment, loosen tighten - loosen tighten ... you usually wont atting the 'spec'd' torque values.

If you dont have access to the OEM torque values/methods, do websearch for the values (principally from MECHANICAL ENGINEERING WEBSITES, etc.), choose the correct bolt materials, etc. "torque values" + bolts + (your choice of material). You will need to know bolt material, number of threads per inch, etc.

;-)

[Gary M]

Sabreman, you could well be over tightening them, I tried what you are talking about once with a long torgue wrench. Sitting on the floor and using one foot to push the torque wrench I was able to get close to 400 lbs of force. You really need to use a torque wrench.

Rich H there are tables for dry torquing which is most common or torquing with a lubricant.