Keel bolt socket

[jimali]

Hi

I have been advised to check my keel bolts by undoing each nut, removing the plate from under, cleaning up, caulking and re torquing the nuts. The boat is out of the water resting on its keel.

The yard have loaned me a large 1" 1/2 (38mm) socket and some large bars to shift them. The problem is that 6 of the studs are so long that the socket does not reach the nuts!!. (See photo - water is from a deck leak - another issue!!)

I need a 4" deep socket that can take a lot of torque (Hunter specify 325 foot pounds).

All suggestions where I can get one or a cunning method of doing the job gratefully received - Mr Google is not being too helpful - but maybe that's me.

Regards

Jim

 

[Rich Stidger]

I would like to know who gave you this advice. Did you run this advice by the Hunter factory? And exactly, what are you "checking for"?

 

[KD3PC]

I have never heard of the process you have been given, but if you go through with it, you will really need a deep socket. Here, in the states, you can get a "tool truck" to get one or on line, something like:

http://www.tools-giant.com/item.php5?id=98834392&lang=en&curr=USD&ref=froogleus

Or even go up to 3/4" drive tools

you may be able to find a 4x4 truck axle socket that is deep enough to reach the nut and still clear the studs.

a wrench will just gum things up, and possibly damage the nuts.

Bests, you would think the yard would have deep sockets, and you may ask them to speak with their tool truck.

Personally I would be more inclined to re-torque them and be done with it

 

[Terry Cox]

Keel Bolts

Seems fishy. If your boat is on the hard resting on its keel I can see some advantage in checking the torque. Removing and re-bedding each nut seems odd advice. A different matter if your keel stub joint is leaking, but that does not appear to be the case.

As Rich says, contact Hunter Marine customer service and seek their advice. Also, most reputable yards should have a socket to do the job.

 

[down_shift]

Try here: http://www.imperial-newton.com/impact+sockets.htm/inch/black-steel/075/6-point/extra-deep/

3/4" drive, impact socket, 1-1/2" AF, 6-point, extra deep 6" internal, black finish

 

[caguy]

Harbor Freight. Uses a six point impact socket as opposed to a 12.

 

[Rick Webb]

Have One Made

Buy a deep socket, take it to a machine shop (or whatever they are called over there) ask them to cut the socket and weld a piece of pipe to it in between the cut pieces to make it longer.

 

[alexco38]

What is the advise based on? Was it loose? Suspect water coming in?

caulking the bottom of the plate is not going to stop water from coming in if you have a leak. You have to separate the keel from the boat (big deal), clean and re-bed the two.

If you just need the re-torque, deep socket is needed. Make sure you get impact type of socket, prefer 6 faced only, as 325 inch/lb is a lot.

 

[Benny17441]

"If it ain't broken, don't fix it." A visual inspection of the keel bolts can tell you if the bolts and nuts are subject of excessive corrosion and yours look fine. Unless the boat has experienced a hard grounding, or there is a leak or separation at the hull/ keel joint I would not mess with that. Boats regularly go 30+ years without having keel bolts re-torqued.

 

[jibes138]

325 foot pounds sounds like way too much torque for those size bolts. Do you have company literature specifying that? What size are the threads? You can get a torque chart based on thread size for stainless steel on the net. Double check that before you proceed. A two foot long wrench will require you to apply 163 pounds to it in a weird position. You will need some hefty tooling if that torque is correct. You can get deep sockets at sears or harbor freight, or search on the net, you will also need a long arm torque wrench. If you break off one of the studs because the torque is too high you will have a huge expense to fix it. Make sure you research this and yes call the factory, I think they are still in business.

 

[seadaddler]

No

Don't take them off looking for trouble and as said if no leaks and keel looks good on outside than leave a lone or check to tighten them only.
Nick

 

[tartansailboat]

The 325 ft lbs sounds high but I got the same number for the one inch keel bolts on my Tartan 30. Be sure the bolts are stainless steel and not bronze or else the 350 ft lbs will certainly strip the studs and then you are really in trouble. You will need 3/4" drive, another Tartan 30 owner used a 3/4" drive socket with a knuckle extension so he could tolerate slight angles. Then he cut a 6" extension bar in half, welded each half to a pipe so he could turn the nut while standing up, used a 4 foot breaker pipe and was able to pull 90 lbs of force to get 90x4 = 360 ft lbs of torque. A man can pull about half his own weight, hence the 4 ft pipe. That still does not solve the issue of the deep socket but the fellow who suggested to cut a deep socket in half and weld each half to a short pipe has the right idea. All this aint cheap, the yard will do it cheaper but they probably will only use a 1/2" drive and a torque wrench for which the max torque is only 250 ft labs, but that may be OK.

 

[Don S/V ILLusion]

As others have said, perhaps more subtly, find another advisor. Removing and reinstalling perfectly sound keel bolts is a solution to a problem you don't have.

 

[tartansailboat]

For what it is worth, I had a big leak in my keelbolts, after a hard few hours sail I would have a few gallons in the bilge, yet at the dock no leak at all. I too reasoned that just by removing the keel bolts, cleaning out the old caulking, re caulking and tightening the keel bolts to the proper torque setting, I would cure the leak. Made no difference at all. But keeping the bolts at the proper torque is still a good idea, just dont bother to remove them, just re torque.

 

[jibes138]

Any leak needs to be cured from the outside at the keel joint. Scrape out all the caulk around the keel joint as deep as you can using a scraper like this one

http://www.lowes.com/pd_505287-1687...pl=1&currentURL=?Ntt=paint+scraper&facetInfo=

Then caulk and fair the joint all around and let it cure. Then torque the keel bolts. This should stop the leak. Trying to stop a leak from the inside won't work well as water pressure is always trying to separate the sealant from the joint.

Here is a torque table for your reference. 325 foot pounds is 3900 inch pounds. Note the table doesn't even go up that high for 1"-14 or 1"-8 threads. http://www.engineersedge.com/torque_table_sae.htm

You have fairly small backing plates and too much force could have several disastrous results. You could strip or gall the threads, you could break the stud or you could cause the fiberglass of the keel stub to fail in compression seriously weakening its' ability to retain the keel. From the scale of your picture using the wire connector in the foreground for scale those don't look like 1' bolts. Torque for a 3/4 bolt is recommended more like 130 foot pounds. Measure the bolts and go from there.

Here is a calculator for axial force for bolt size and torque. 3900 inch pounds on a 1 inch bolt will be 19,500 pounds of force. This force will be concentrated over the area of the backing plate. Polyester resin FRP has a compression strength of about 21,000 PSI So you can see you are approaching the strength of the material depending on how many square inches your backing plates represent. If your bolts are only 3/4 inch diameter the clamping force goes to 26,000 pounds and could cause the fiberglass to fail in compression. A safety factor of 2 would suggest not applying more than 10.500 PSI to the fiberglass. 130 foot pounds on a 3/4 bolt is 10,400 pounds of clamping force.

http://www.engineersedge.com/calculators/torque_calc.htm

Assuming you have say 7 keel bolts with 325 foot pounds you will be clamping your keel with 136,500 pounds of force on the keel joint. You can run your own numbers for your actual situation using these calculating tools. Good luck.