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Keel bolt torque

Jan 10, 2018
209
Beneteau 331 Halifax
Hi there, I am the proud owner of a new to me Beneteau 331. I am unable to locate anywhere the torque specs for the keel bolts, not even in the owner's manual. Anyone have any ideas?

Thanks,
Mike Casey
Halifax, Nova Scotia, Canada
 
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Jan 12, 2016
140
Beneteau 311 Seattle, WA
Hi there, I am the proud owner of a new to me Beneteau 331. I am unable to locate anywhere the torque specs for the keel bolts, not even in the owner's manual. Anyone have any ideas?
Congrats on the new 331! I just looked in my various copies of manuals and only found "Check keel bolts for tightness." in the launch instructions, but no other details! Seems like you've found a detail that isn't in the normal docs....
 
Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
IIRC, you can measure the head of the diameter, and you should be able to locate a cross reference for torque? It was in a previous post on the forum.
 
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May 24, 2004
6,746
CC 30 South Florida
I don't think the boat manufacturer's know. Torque specs are usually reserved for clean, machined parts to close tolerances. Dirt or corrosion present will yield unreliable readings. Just tighten individually by feel to where there is no slack being careful not to overtighten. It sort of follows the "good enough" principle.
 

Ted

.
Jan 26, 2005
1,212
C&C 110 Bay Shore, Long Island, NY
Your torque specification will be based on the diameter of the bolt/stud and the alloy of the metal used to make it. Don't guess. Use a properly calibrated torque wrench. Large diameter bolts take an enormous amount of force to tighten them. You won't be able to get anywhere near the proper torque with a standard size ratchet wrench. I would guess that a boat of your size might need in excess of 200 ft. lbs. of torque. Many times the bolts are of different diameters and will have different torque specs. Call the manufacturer for the proper specs.
 
Jan 10, 2018
209
Beneteau 331 Halifax
Interesting, thank you. I have written to Beneteau USA. If they let me know I will update the post.
You are correct about the tightening them. On my C&C 30 after calibrating the wrench, I could not move them and that was with a very long wrench
 

MitchM

.
Jan 20, 2005
951
Nauticat 321 pilothouse 32 Erie PA
original keel bolts were likely torqued to design spec unloaded --i.e. with keel supported --to prevent distortions in the mating surface. if you are re torquing or checking torque don't do it in the water , do it on land where weight of the hull is supported as much as possible. some boat manufacturers used anti-seize compound on the threads to get an even torque up, and assist you to remove the keel in the future . what the torque sequence is on the bolts is also important . As usual, the torque sequence should start from the center bolt and work your way alternating aft to bow towards the ends, tightening in 3 passes up to the final torque value. final torque value is designed by manufacturer based on bolt diameter-- could be 130-200 ft #S for a boat of this size. write down what your final torques are for each bolt just for future reference and compare to the design specs...
 
Jun 21, 2004
1,825
Beneteau 343 Slidell, LA
Mike,
Congratulations on the Beneteau 331. I spent many charter days on a 331 and enjoyed it tremendously.
Hopefully you will have lots of good times aboard.
I found an article that I had in my files about keel bolts. I don't have a source for this information, so take it for what its worth. Seem that I ran across information directly from Beneteau about an order number for ss keel bolts & torque values, but I couldn't locate it. You should check with Beneteau to confirm the information that I am attachinging.
 

Attachments

Dec 31, 2016
319
Beneteau Oceanis 351 Charlottetown
Here is the specs direct from Beneteau:
TABLE 6.5.1


DACROMATISED STEEL BOLTS TYPE 8-8.

DIAMETER M14 M20 M24 M30

TORQUE in M.Kg - minimum 5 13 23 45

TORQUE in M.Kg - maximum 9 27 46 90

TORQUE in ft.lb - minimum 36 94 166 325

TORQUE in ft.lb - maximum 65 195 333 651

TABLE 6.5.2

STAINLESS STEEL BOLTS TYPE A4-70 and A4-80

DIAMETER M14 M20 M24

TORQUE in M.Kg - minimum 5 16 28

TORQUE in M.Kg - maximum 11 32 55

TORQUE in ft.lb - minimum 36 116 203

TORQUE in ft.lb - maximum 80 231 398

TABLE 6.5.3

STAINLESS STEEL BOLTS TYPE A4-55

DIAMETER M30 M36 M42

TORQUE in M.Kg - minimum 19 33 52

TORQUE in M.Kg - maximum 38 65 104

TORQUE in ft.lb - minimum 137 239 376

TORQUE in ft.lb - maximum 275 470 752

Tightening must be done using: - Multiplier x4 0-250ft-lbs

- Torque wrench

IMPORTANT: Use the proper torque as showing in table 6.5.1, 6.5.2 and 6.5.3 – never exceed it
 
Jan 10, 2018
209
Beneteau 331 Halifax
What does "Tightening must be done using: - Multiplier x4 0-250ft-lbs" mean?
I take it that each of the numbers corresponds to the respective diameters?
 
Dec 31, 2016
319
Beneteau Oceanis 351 Charlottetown
I believe that refers to a torque multiplier ,is the tool used instead of a longer breaker bar or torque wrench, (fits in tighter spots). Do you know what dia. bolts you have? My 351 has 20mm dia, suppose to take a 300mm socket ,but the heads are rusted down to approx. 24mm, in the process of replacing now. ( Btw, mine came from over your way, St. Margaret's Bay)
 
Jan 10, 2018
209
Beneteau 331 Halifax
You are very close by! I don't know what they are just yet, but I'll check. Thanks!